Wild guesses do not fix cars. March 20, 2012 6:28 AM   Subscribe

Automotive questions generally, but specifically those that mention a Check Engine Light, repeatedly get flooded with well-meaning but ultimately pointless (and often directly unhelpful) anecdata about their own check engine light experience in their own (similar or completely different) cars. It is in the best interests of Askme if that kind of thing just stopped.

The question that finally brought this to a head is this one, but this is extremely common (almost to being standard form) and I find it very frustrating and it has to be confusing for the asker. They get lots of stuff that seems like 'information' and almost none of it is at all relevant. Knowing that a CEL is on is not even close to being able to guess at a cause of the problem. To use an analogy, imagine a tech support person reading a forum and seeing the following:

OP: "I have a windows machine and an error window came up - is this a major problem or can I ignore it"

Then, while one lone voice says "What did the error window actually say?" the rest of the thread is filled with people saying "when my mac had an error message it was because my internet connection was down" and "My error message was on a Windows machine like yours and it was because my printer had run out of ink - just ignore it" or "My error message was because I had a virus - YOU PROBABLY HAVE A VIRUS OMG" or "My error message was because my email account couldn't check messages - maybe you've been hacked? Change all your passwords just in case".

That's a pretty apt analogy in the vagueness of 'error box' and CEL and and it's kind of amusing now that i read it back. But it is exactly what happens in automotive questions. It is borne of people desperately wanting to answer questions in a helpful way but it needs to be said that this kind of anecdotal rubbish is directly and explicitly unhelpful and people should be more aware of this and knock it off. In the interests of getting people to understand precisely what they are posting, I'll try and explain why it is unhelpful and pointless. It doesn't help the OP at all, which is the prime purpose of AskMe.

The check engine light is not something you can use to diagnose a problem. On its own it doesn't actually tell you ANYTHING AT ALL. Consequently because you had a check engine light on in your own car and later a problem was found does not imply any kind of direct cause and effect that can be extrapolated backwards. Your anecdote about your own check engine light is likely of zero use in everything other than blind luck that this is miraculously the same issue. Even worse, implying that a CEL can mean a particular fault without further investigation is directly damaging and is likely to cause the OP to make a badly informed decision. If you don't know that a CEL is not enough for even a vague diagnosis then you don't understand it and should refrain from making wild guesses. In the nicest possible way it doesn't matter ONE LITTLE BIT what caused your own engine light, even if it is the same model of car, unless you know for a fact it was the exact same trouble codes. Even then, the same trouble codes can mean three or four likely causes.

To repeat, The CEL is NOT a symptom. It never is. You can assume precisely nothing from knowing the CEL is on. If you think you can, you are wrong. It is just a light to signify that the ECU has detected symptoms and they need reading and understanding with a code checker. The check engine light is triggered by a significant number of sensors and parameters and produces many conclusions from serious to irrelevant (emissions ECL triggers I am looking at you) and it really is no help other than 'there's something you need to look at'. 90% of these conclusions cause the ECU to determine that something needs further investigation and so it illuminates the CEL - the 'please take me to someone that can look at this and see what needs fixing' light. It is a very complex system with a very limited means of transmitting to the owner that it needs investigating. The fact that it uses a single light for everything does not mean that it is a small variety of potential issues being indicated.

Only with the codes supplied from the ECU when a CEL is triggered can anyone possibly make any sort of educated guess as to the cause and if anyone tries, they are being anything from directly unhelpful to just adding noise. Even then, a code can often only produce a system error of several components and the system then needs to be checked over. Evap system codes is often the fuel cap, for instance, but not always as other component failures produce the same code. This is a very common 'answer' - "My ECL was the fuel cap - check that!". It's just.... pointless noise. There are very few CEL codes that produce a direct fault, so that code 11356 means that component X is wrong.

So in short, please do stop doing this. It is rare that any Askme posts enough information for a diagnosis in most automotive threads anyway (a lot of my answers will suggest several causes and means to narrow them down for this reason) and wild and uninformed guesses are a problem in almost every single one but at the very least a greater understanding of the CEL would start to help askers and answerers alike. The sheer volume of noise in automotive threads drives me nuts and hopefully if awareness is raised of the problems of this kind of answer then at least some people will get it. At the very least, linking to this metatalk thread in questions where this is starting to happen may at least quell it a little.

Ok. I have taken a deep breath now.
posted by Brockles to Etiquette/Policy at 6:28 AM (222 comments total) 29 users marked this as a favorite

Oh hey Brockles, been meaning to ask you, since you disagree about the downshifting thing: Is Cecil Adams from the straight dope wrong when he says: "the pretty much unanimous opinion of people in the automotive business is that downshifting to slow the car is a completely stupid and pointless practice that increases the risk of a premature (and expensive) clutch job."
posted by Grither at 6:36 AM on March 20, 2012


I see what you're saying and respect what you're trying to accomplish, but these things hardly ever go well. We've lost more subject matter experts after this sort of MeTa than I like to think about, so I hope you're not pinning future involvement on folks taking this to heart.
posted by batmonkey at 6:37 AM on March 20, 2012 [9 favorites]


It is like when a 2 year old starts crying. Could be he fell down the stairs. Could be he can't flip the page in his flip book. Could be hungry. Could be over tired. Could be about to projectile vomit eight ounces of Cheerios (yeah). More data needed!
posted by seanmpuckett at 6:38 AM on March 20, 2012 [7 favorites]


My car made a noise the other day. Should I stop driving it?
posted by routergirl at 6:40 AM on March 20, 2012 [6 favorites]


Is this a thread I'd need a car to understand?

Ha ha ha...! *parks bike next to truck, perhaps a bit sheepishly*
posted by barnacles at 6:45 AM on March 20, 2012 [1 favorite]


My car made a noise the other day. Should I stop driving it?
I'd nibble a corner and see how you feel tomorrow.

As to the issue that Brockles mentions, it's a symptom of people wanting to help even if they can't offer any qualified advice. I doubt it will ever completely stop.
posted by arcticseal at 6:48 AM on March 20, 2012 [1 favorite]


Hm, perhaps I should've done that via messaging instead, as that seemed to come off kinda fighty, when really, I just think you're awesome for your answers in all the auto questions thread. So feel free to ignore me! Also, I totally agree about the CEL. Hopefully some folks'll take your post to heart!
posted by Grither at 6:48 AM on March 20, 2012


I totally agree -- but I also think that our very human desire to be helpful and to tell stories ("hey, I had a problem just like yours, and here's how it turned out...") will trump this every time. People almost universally have experience with cars, whether as drivers, passengers, or having to swerve out of the way on their bicycle, so it's a topic about which everyone has a multitude of strongly-held opinions and deep experiences.

In other words, good luck, but I don't expect to see any changes.
posted by Forktine at 6:49 AM on March 20, 2012 [1 favorite]


Yeah, this is certainly the downside of asking "real" questions on a website like this.
With nearly any question that actually has a concrete non-opinion answer, this place looks like Yahoo. The matter is only compounded when the question involves something skilled, like this, or IT, or pretty much everything.

Imagine if a dentist came here asking about a tricky root canal she needed help with, and then people chimed in about how important it is to floss daily, or others talking about their own root canal experience from a patient's perspective.

We've lost more subject matter experts after this sort of MeTa than I like to think about

We lose subject matter experts because of the thing this post is talking about.

In real life, I'm a network engineer for a massive-huge organization, with a focus on perimeter security. I could probably help a lot more people in Ask than I usually do, but it is just usually too painful.
posted by Threeway Handshake at 6:56 AM on March 20, 2012 [6 favorites]


"hey, I had a problem just like yours, and here's how it turned out..."

Really, the only issue that I am addressing and hoping to achieve something is that people need to understand that having the CEL come on is not at all, in any way, "I had a problem like yours" but lots and lots of people assume it is.

The people that give very adamant sounding answers based on that assumption are a step beyond this that I don't think will ever stop, but baby steps... baby steps...


My car made a noise the other day. Should I stop driving it?

If it is a high pitched whining, it usually stops when you get out....

(JOKING, wifey! Please don't put razor blades in my pillow!)
posted by Brockles at 6:57 AM on March 20, 2012 [10 favorites]


Man Brackles, sounds like you need a flush and fill.
posted by Brandon Blatcher at 6:59 AM on March 20, 2012


I'm calling him "Man Brackles" from now on.
posted by gman at 7:00 AM on March 20, 2012 [5 favorites]


Is Cecil Adams from the straight dope wrong when he says: "the pretty much unanimous opinion of people in the automotive business is that downshifting to slow the car is a completely stupid and pointless practice that increases the risk of a premature (and expensive) clutch job."

I've never heard anyone in the auto industry say that, and anyone that does is an idiot. Totally wrong. The idea that downshifting doesn't do anything and/or that it causes premature clutch wear is based on absolutely nothing and was urban myth I associated with non-industry, to be honest.
posted by Brockles at 7:00 AM on March 20, 2012 [3 favorites]


I feel as though I could boil this post down even further:

[Q]uestions generally...repeatedly get flooded with well-meaning but ultimately pointless (and often directly unhelpful) anecdata about their...experience... It is in the best interests of Askme if that kind of thing just stopped.

I don't think that's realistic, though, so I think we all just have to bear our crosses as best we can (for you, it's auto threads, for me, it's skin care and the different ways commenter choose to interpret the term "acne").
posted by ThePinkSuperhero at 7:01 AM on March 20, 2012


Grither, the important distinction is between engine braking to lessen accelleration down a hill, and downshifting to slow the car to eventual stop. The former is a good idea, the latter is a waste of effort and clutch-frictiony-bits. If you read the complete Straight Dope article again that's basically what it says.
posted by helicomatic at 7:01 AM on March 20, 2012 [2 favorites]


No. That's still wrong. Dragging the clutch (the transition between fully engaged and fully disengaged) wears the clutch, period. Either accelerating or decellerating it makes no difference. The only thing that increases wear on a clutch is a long clutch drag or a high disparity between road speed and rpm (sudden change in speed for the clutch).

Basically, if your foot is off the clutch, there is no wear. If your foot is on the clutch for a small amount of time, you have minimised wear. The clutch doesn't care whether you are speeding up or slowing down.
posted by Brockles at 7:10 AM on March 20, 2012 [6 favorites]


Yeah, this is both frustrating and definitely not going to go away. I want to second batmonkey's sentiment that I hope this tendency isn't going to drive you away from MeFi.

Not to derail, but it's not limited to car questions, either. Basically every question that begins "I know you're not my lawyer but ... " is a question that should be answered "Get a competent lawyer in your jurisdiction and ask him or her what you want to ask us. Seriously just get a damn lawyer already." The ethical rules are broad enough that I wouldn't feel comfortable even just telling somebody "oh, you don't need a lawyer for that" because it might be construed as legal advice.

I can only imagine what it must be like for doctors on MeFi.

posted by gauche at 7:10 AM on March 20, 2012 [1 favorite]


I feel your pain every time someone asks what it takes to have a friend be their wedding officiant. Authoritative, definitive answers from people who know they're right, based on their own, actual experience, but with no awareness of the wide, crazy, completely-unpredictable variation in marriage laws, and no consideration of the OP's jurisdiction.
posted by MrMoonPie at 7:10 AM on March 20, 2012


> The idea that downshifting doesn't do anything and/or that it causes premature clutch wear is based on absolutely nothing and was urban myth I associated with non-industry, to be honest

It causes clutch wear just like upshifting would since you're engaging it under load. While I don't think it's a huge deal a clutch will indeed last longer if one doesn't use engine braking.

Now, the added control one has by being in gear while braking could be given greater weight then extending clutch life (although modern manual clutches, as rare as they are, are in general very durable), but that's a slightly different argument.

Anyway, any driver who doesn't have a Bluetooth ODBII reader for their smartphone that can read fault codes and other engine data is unhip.
posted by Burhanistan at 7:11 AM on March 20, 2012 [6 favorites]


Brockles: "No. That's still wrong. Dragging the clutch (the transition between fully engaged and fully disengaged) wears the clutch, period. Either accelerating or decellerating it makes no difference. The only thing that increases wear on a clutch is a long clutch drag or a high disparity between road speed and rpm (sudden change in speed for the clutch).

Basically, if your foot is off the clutch, there is no wear. If your foot is on the clutch for a small amount of time, you have minimised wear. The clutch doesn't care whether you are speeding up or slowing down
"

But by this logic, you are increasing wear in the clutch if you are downshifting to slow the car down, no? If I shift from 1 through 5 while accelerating, then break to stop, I change gears 4 times. If I shift 1-5 and then 5-1 to slow/stop, I change gears 8 times. Is that not doubling the wear on the clutch?
posted by Grither at 7:20 AM on March 20, 2012 [2 favorites]


Tread is now about downshifting. Thanks Grither.
posted by Threeway Handshake at 7:22 AM on March 20, 2012 [7 favorites]


I can only imagine what it must be like for doctors on MeFi.

YANMD but what's this thing on my arm? It's been there for like a week and it's kind of itchy.

[blurry photo of arm with red mark washed out by iPhone flash]

--

"Bedbugs. Burn all your possessions and move to the North Pole."

"Oh, I had that once. It turned out to be an irritation because I'm allergic to the exhaust from the pork rendering plant I live in. Do you live in a pork rendering plant? It might be that."

"Arm cancer."

"I don't have arms, but I saw some arms in a movie once and they had a mark that looked sort of like that. You might want to contact the screenwriters to see what they used as a reference. I think it was called 28 Days After or something like that."
posted by griphus at 7:24 AM on March 20, 2012 [38 favorites]


I think it's the nature of people to want to help without realizing that often trying to help is making matters worse.

Yesterday I started crafting a plumbing-related question and after listing all the things I know it isn't I realized people would just ignore all that and tell me their best guess of what they think it is, which would most likely be all the things I know it isn't and I knew if I posted it I would just get frustrated at all the unhelpful responses. But of course you can't really get mad at people who are trying to help.

I love AskMe, but over the years I've learned that it has its limitations and there will always be a certain percentage of answers that are well-meaning yet maddening.

FWIW, I had at least three mechanics tell me the check engine light in a Subaru Forrester just comes on all the time and it's best ignored. So, obviously, the correct answer is to ignore your light. Glad I could help.
posted by bondcliff at 7:25 AM on March 20, 2012 [2 favorites]


Theoretically, but you're using the car for what it is for. You'll decrease tyre wear if you leave your car in the garage, too, but that is also pointless. The point is it doesn't wear it any more and this talk o 'premature clutch failure' is panic inducing in people.

A clutch is a wear component just like brake pads are. It will need replacing at least once in the life of the car. That's no big deal. This fallacy that engine braking suddenly causes major clutch wear is an issue, because downshifting is an important part of vehicle stability and control under braking and so people shy away from it because they think that all of a sudden their clutch will explode.

Gentle acceleration and gentle decelleration produce minimal, normal and expected, clutch wear in a component that has a limited life. It does not create wear beyond what should be expected from brake pads, disks, tyres etc.
posted by Brockles at 7:25 AM on March 20, 2012 [12 favorites]


The "Check Engine" light would be better named the "Spend Money" light. Not only is the light itself deliberately vague, you need a special tool to get a code that you need access to a special database to be able to look up just to find out what the *problem* is, let alone the solution.

The Windows error message box is a very apt analogy, except imagine that the Windows error message box never had any text. And you had to call a Microsoft-certified technician (at $80/hr) to have them tell you what the error was.

Would you stand for that? Then why do people do so for their cars?
posted by DU at 7:26 AM on March 20, 2012 [4 favorites]


Tread is now about downshifting. Thanks Grither.

Yeah, I could use help with this teeth gritting.
posted by Brockles at 7:26 AM on March 20, 2012 [4 favorites]


Threeway Handshake: "Tread is now about downshifting. Thanks Grither"

Fortunately we're all agreed on the CEL thing. And I've been told recipes are not allowed any more. Though I think it might be fun to cook something wrapped in tinfoil and placed in the engine for a while.
posted by Grither at 7:27 AM on March 20, 2012 [1 favorite]


> Would you stand for that? Then why do people do so for their cars?

Most shops nowadays will scan your fault codes for free.
posted by Burhanistan at 7:28 AM on March 20, 2012 [1 favorite]


The Windows error message box is a very apt analogy, except imagine that the Windows error message box never had any text. And you had to call a Microsoft-certified technician (at $80/hr) to have them tell you what the error was.

Would you stand for that? Then why do people do so for their cars?


But a car is a very complex machine that travels in a way that could kill lots of people if it failed in the wrong place, never mind at speed. It is more complicated than a computer because it is a complex mechanical machine controlled by several computers and safety implications are high if it is badly maintained.

I don't understand why people haven't worked out that the day of the shade tree mechanic disappeared with high emissions control and the demands we place on cars nowadays. They're hard to diagnose these days.
posted by Brockles at 7:30 AM on March 20, 2012 [4 favorites]


My owner's manual (2003 VW Passat) actually says downshifting to slow down is not recommended. I don't think they're suggesting doing all your braking with the clutch disengaged, though. I don't have it here with me, but I think it had something to do with the "high compression" engine, same reason I have to put the expensive gas in it.
posted by ctmf at 7:33 AM on March 20, 2012


To be more complete, I'm totally in agreement with Brockles about this. His answer to the original question was about engine braking down a hill, which someone said was a bad idea, which it isn't. I was thinking more of the situation of raking all the way down to first every time you stop as a waste of effort, not downshifting to decelerate in general.
posted by helicomatic at 7:36 AM on March 20, 2012


Downshifting is kind of a dance anyway. For most daily circumstances you shouldn't downshift to where the revs would spike in the next lower gear, but rather when it is in the middle or lower speed range of a particular gear. That way, you'll have enough torque if you need to accelerate again.
posted by Burhanistan at 7:36 AM on March 20, 2012


To be fair, a handheld OBDC reader and the Internet can help a fairly mechanically-inclined person track down some of the simpler issues and save some money. I feel competent to fix my own cooling system fault (which I did) but not a fuel trim problem (which I let the dealer do.)

That's not to argue with your premise that the MIL doesn't mean anything by itself. Just that it's not necessarily an automatic "omg take it to a professional immediately."
posted by ctmf at 7:37 AM on March 20, 2012 [1 favorite]


Brockles, I feel your pain when I see some of the answers to medical question in AskMe. But as Homer Simpson would say "Yeah, but what are you gonna do about it?"
posted by TedW at 7:38 AM on March 20, 2012


I had at least three mechanics tell me the check engine light in a Subaru Forrester just comes on all the time and it's best ignored.

This is relevant to my automobile. But when mine came on it was telling me that I had a leak in the ... oh I don't even remember but my mechanic fixed it promptly. In my old car you could stick a paperclip into this little thing under the floor mats and it would blink a certain number of times and you could look up that blink pattern in a manual and THAT would tell you what was wrong. So I do try to ask people if they have a car where you can do that, that was badass.

This will be a good MeTa thread to link to for future check engine light questions, at least.
posted by jessamyn (staff) at 7:39 AM on March 20, 2012 [6 favorites]


Knowing that a CEL is on is not even close to being able to guess at a cause of the problem.

Man I want to agree with your overall point but sometimes the above statement is wrong. EG: Low mileage third gen Dakota with random seeming illumination of the CEL = user isn't tightening the gas cap properly after every fill. I mean it might be lupus some serious engine problem but I'd take long odds against it.

They're hard to diagnose these days.
This isn't true probably 80+% of the time with cars that are a few years old. Sadly the same things tend to go wrong with any particular automobile and it's often pretty easy to figure out what is wrong. The other 20% of the time can drive you batty but most of the time the problem is some well known problem.
posted by Mitheral at 7:39 AM on March 20, 2012 [2 favorites]


Oh hey Brockles, been meaning to ask you, since you disagree about the downshifting thing: Is Cecil Adams from the straight dope wrong when he says: "the pretty much unanimous opinion of people in the automotive business is that downshifting to slow the car is a completely stupid and pointless practice that increases the risk of a premature (and expensive) clutch job."

Who uses a clutch to downshift ? Hell, after first, who uses it to upshift ?
posted by Pogo_Fuzzybutt at 7:40 AM on March 20, 2012 [3 favorites]


People who have cars with manual transmissions. Crazy, huh?
posted by Burhanistan at 7:44 AM on March 20, 2012 [1 favorite]


People who have cars with manual transmissions. Crazy, huh?

It's the Linux of transmissions. Technically superior but more often than not it's just a pain in the ass.
posted by bondcliff at 7:47 AM on March 20, 2012 [14 favorites]


♬ Spring! ... Spring is int he air! ♬

Bluebirds and cockleshells, ♪♪♪
warm breezes and ringing bells

short shorts and garden rakes,
motorcycles and sponge cakes
♪♪
Spring! spring is in the air!

Endless MetaTalks and primary seasons
Rototillers and mysterious lesions ♪

There♪
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No♪
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Like♪
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(remember.. winter is coming)
posted by edgeways at 7:47 AM on March 20, 2012 [1 favorite]


This isn't true probably 80+% of the time with cars that are a few years old.

The two mechanics that share my workshop with 40 years experience between them (dealer trained and now running their own shops) disagree entirely with you. The amount of detail that triggers the CEL is enormous. The thing being on is not at all any kind of indication of what the problem is. Not even close.

Yes, the same sort of fault codes mean the same sort of problems 80% of the time, and often a car coming in with external symptoms (poor running, etc, bad throttle response) and a check engine light can be guessed at, but the codes are a vital part of diagnosis now for even the simplest issue as so many things can give the same external signs and a CEL.

Regardless, a CEL and no other symptoms is totally random. It could be literally ANYTHING so this does not wash.
posted by Brockles at 7:48 AM on March 20, 2012 [1 favorite]


Most shops nowadays will scan your fault codes for free.

Did that once. Didn't do me a lick of good without the database. And an interpreter.

But a car is a very complex machine that travels in a way that could kill lots of people if it failed in the wrong place, never mind at speed. It is more complicated than a computer because it is a complex mechanical machine controlled by several computers and safety implications are high if it is badly maintained.

Exactly! So why make maintenance more unlikely by lumping real problems in with non-problems and upgrade treadmills that people will just ignore? "Pfff...that thing again. Last time I starved my kids to take it in all they did was reset it and tell me they couldn't find the problem."

If real problems are more clearly indicated and available to scrutiny, people are more likely to trust and obey them.
posted by DU at 7:49 AM on March 20, 2012 [1 favorite]


Man I want to agree with your overall point but sometimes the above statement is wrong. EG: Low mileage third gen Dakota with random seeming illumination of the CEL = user isn't tightening the gas cap properly after every fill. I mean it might be lupus some serious engine problem but I'd take long odds against it.

Yes, but without asking "does it happen after you fill up with fuel?" and confirming the CEL is an evap system code to be sure that is what it is is required. It's something you can check for free, but it can't be assumed that the CEL is because of that unless you tighten the cap and see if it goes away.

Not enough info.
posted by Brockles at 7:50 AM on March 20, 2012 [2 favorites]


> Did that once. Didn't do me a lick of good without the database. And an interpreter.

All of the fault codes are available on the internet, though.
posted by Burhanistan at 7:50 AM on March 20, 2012 [1 favorite]


I've never heard anyone in the auto industry say that, and anyone that does is an idiot. Totally wrong. The idea that downshifting doesn't do anything and/or that it causes premature clutch wear is based on absolutely nothing and was urban myth I associated with non-industry, to be honest.

If you click and read this link, you will have heard someone in the auto industry say that. Forgive me if I put more credence in their opinion than in yours. [/ appeal to authority]
posted by Kirth Gerson at 7:53 AM on March 20, 2012 [1 favorite]


All of the fault codes are available on the internet, though.

Yes, there are places on the internet that will turn a terse number into a slightly less terse series of letters. I'd hardly call it informative, though. No indication of the real issue or the seriousness, for example.
posted by DU at 7:53 AM on March 20, 2012



People who have cars with manual transmissions. Crazy, huh?


You don't need to clutch to shift. This will save clutch wear and time once you master it as a skill. If you drive a semi or other large truck, this will be a necessary skill. You can always tell a rookie truck driver by how long it takes to shift - double clutching is a time killer.

Next up - gear skipping.

That said, the manual transmission is going the way of the dodo. It interferes with eating breakfast and texting on your commute. the CVT is the way of the future - your car as a golf cart.

Sigh....
posted by Pogo_Fuzzybutt at 7:55 AM on March 20, 2012 [4 favorites]


I just had a "Who's on First?" moment with my newly licensed daughter about a month ago. I am not even sure how it came up although we were talking about an old British car I keep in the garage. She wanted the spot for her car.

"What is a clutch?"
"You know, the thing you push in when you change gears."
"I thought that was the brake."
"No, the brake is used when you are stopping the car. How did you pass your road test?"
"Dad, I push the rectangular pedal next to the long skinny one when I shift gears."
"Well what do you do with the pedal on the other side of the rectagular one?"
"That is the emergency brake."
"Oh. You're talking about an automatic transmission. I was talking about a manual one."
"What is a manual one?"
"One where the driver makes the gear change decisions."
"Oh. What is a transmission?"

I think we could have gone on for a while before I just said, "Make sure you have your AAA card with you whenever you drive."
posted by JohnnyGunn at 7:56 AM on March 20, 2012 [8 favorites]


> You don't need to clutch to shift.

Maybe if you have a high end racing car, but most econboxes wouldn't work that way.
posted by Burhanistan at 7:57 AM on March 20, 2012


Maybe if you have a high end racing car, but most econboxes wouldn't work that way.

You can clutchless shift pretty much any gearbox, but racing boxes are by far the easiest and really don't need the clutch if you have a modicum of skill past pulling away. Road car syncro boxes are much harder and wear things pretty badly if you do it too much.

Forgive me if I put more credence in their opinion than in yours. [/ appeal to authority]

I know the Car Talk guys say that, but the way they present it is wrong. Downshifting and using the gears to slow the car will use less brake wear for a proportionally smaller clutch wear. Downshifting wears the same amount as one upshift. A clutch has a life of many thousands of shifts and to suggest that it is 'best' to avoid something as dynamically helpful as downshifting just so you get to replace your brakes more than the clutch is nonsensical.

It is not 'better' to avoid downshifting. It is better for the life of your clutch in isolation but it is worse for your brakes, worse for your vehicle control and as such is bad practice. If your only parameter is clutch wear, then fine. It's bad. So is upshifting and you should always change from 2nd gear to 5th and miss out 3rd and 4th. That is equally nonsensical as 'you shouldn't downshift to slow the car'.

Any gear shift wears the clutch. It's a wear component. That doesn't mean that shifting is bad, it's just part of how you use the car. People always suggest that downshifting will wear things out. This is not true. Using the clutch wears it out. This should be just accepted and better driving practices promoted.
posted by Brockles at 8:07 AM on March 20, 2012 [10 favorites]


Brockles, I agree with you. It's annoying and I wish it would stop.
posted by empyrean at 8:09 AM on March 20, 2012


Is this a Metatalk post or a soapbox?
posted by tommasz at 8:11 AM on March 20, 2012 [2 favorites]


The amount of detail that triggers the CEL is enormous. The thing being on is not at all any kind of indication of what the problem is. Not even close.

Ah, you are talking about CEL problems needing expert interpretation rather than all car problems. That's a somewhat more reasonable observation.

Keep in mind the mechanics in your shop are working under a selection bias, only the people who can't figure the problem out themselves bring the car to a shop.

Yes, but without asking "does it happen after you fill up with fuel?" and confirming the CEL is an evap system code to be sure that is what it is is required. It's something you can check for free, but it can't be assumed that the CEL is because of that unless you tighten the cap and see if it goes away.

Well, ..., ya. You try rigourously tightening the cap and see if the problem goes away. Point being this is a problem that someone on the internet can diagnose with probably 99% accuracy knowing make, model, year and the intermittent nature of the CEL. I know because it was diagnosed for me in just that way when I had that vehicle and I've diagnosed that exact same problem many times since.

There are lots of problems like that. IE: symptoms that occur with such frequency and are almost always the fault of a particular component. Dodge equipped with ignition resistor suddenly won't start -> replace ignition resistor. V6 Fiero died suddenly and won't start -> distributor sensor has failed. Izuzu 1.6L4 suddenly low on power -> jumped timing belt.

And I'm sure enthusitists of other makes/models could list dozens of CEL light problems that are almost always the same problem.

But really your concern is the well worn path that many doctors, laywers and other professionals have tread on the pages of Meta. The concern that only a professional with detailed knowledge of the problem and often in person attention can help with broad classes of problems. Here's hoping you don't flame out over it; I'd hate to see your opinion silienced on automotive topics.
posted by Mitheral at 8:11 AM on March 20, 2012


Maybe if you have a high end racing car, but most econboxes wouldn't work that way.

I'll grant that some transmissions are easier to do this on than others, sometimes by design, but all of them are capable of it.

The clutch exists to unload the driveline, so that the gears can be manipulated into place on the drive spline.

If you unload the driveline in another way, you can manipulate the gears freely. For example, turn the engine off - you can put the shifter into any gear you like.

If the engine is running and the car is in motion, then you need use the throttle to unload the driveline.

Now, yes, if you do it badly, you can damage things over time. It's a skill, after all.

The car should always be in gear when in motion, downshifting saves fuel, and if your foot is on the clutch, you are wearing it out.
posted by Pogo_Fuzzybutt at 8:20 AM on March 20, 2012 [1 favorite]


Point being this is a problem that someone on the internet can diagnose with probably 99% accuracy knowing make, model, year and the intermittent nature of the CEL.

I have a 2001 Chevy Tahoe with a constant CEL for the past 3 years, except for a few times when it goes away for a little while. Please diagnose.
posted by kiltedtaco at 8:21 AM on March 20, 2012


So I just wanted to chime in that anyone with an android phone has access to a BEAST of a code scanner with the Torque App. There is also a free version with more features. There's also Dash Command, but that's more for geeks than techs.

Torque + this bluetooth OBD2 plug-in = win!

Really, the nicest part is that the code database is built in and constantly and persistently updated. $26 for a full-featured OBD2 is pretty sweet.
posted by TomMelee at 8:27 AM on March 20, 2012 [16 favorites]


kiltedtaco: "I have a 2001 Chevy Tahoe with a constant CEL for the past 3 years, except for a few times when it goes away for a little while. Please diagnose."

Definitely safe to eat.
posted by Grither at 8:28 AM on March 20, 2012 [2 favorites]


Oh, you meant the gas cap. Honestly, I think the point with that is more that it takes two seconds to tighten it and see if that fixes it, and you aren't really "diagnosing" the issue as much as trying a really trivial fix. It's worth trying, but that's about the only thing like that. "Replace your ignition resistor" isn't quite the same magnitude of a fix.

But yeah, I still want to know.
posted by kiltedtaco at 8:30 AM on March 20, 2012


This is a hard sort of problem to solve; talking about it like this isn't a bad idea (and for specific cases may help a bit to keep it in folks' minds going forward) but ultimately this is indeed just part of the cost of having a generalist Q&A site that doesn't require expert screening or whatnot.

I think the CEL thing may be a potent example of a couple of the amplifying factors for this stuff:

1. The vagueness of the question, and
2. The universality of the superficial features of the scenario.

I've found that as a general rule, greater specificity in the question's framing helps reduce the number of "man, here's my anecdote about the general subject" answers because it's at least clearer to potential answerers if their experience lines up with what's being asked about. More general "my car has a light on" questions don't have that same screening effect.

But there's vague questions about niche things (e.g. an otherwise non-detailed question about a very specific pair of medical symptoms, or general request for guidance resurrecting a specific piece of garage sale electronics, etc), and then there's vague questions about things that have a very universal appeal (seeing an engine light come on in a car, dating someone, preferring a book or three from a specific genre). And with the niche stuff you get some pre-filtering of folks who might like to try and help but immediately realize that they don't have that niche experience; for the universal stuff, that stage of filtering doesn't happen so much, because it's such a broadly common kind of experience.

Understanding this doesn't make it better, and to some extent just makes it hard to believe it will get significantly better (because how do you fix people identifying with unspecific questions about universal experiences?), but it may help at least to keep in mind that this kind of amplifying phenomenon is what's driving it, rather than people just being bloodyminded for no reason. It's always a lot more noticeable when you're the expert among folks who are dropping lay advice into a thread, of course.
posted by cortex (staff) at 8:32 AM on March 20, 2012


Get a bus pass, jerks.
posted by Alvy Ampersand at 8:32 AM on March 20, 2012 [5 favorites]


I have a 2001 Chevy Tahoe with a constant CEL for the past 3 years, except for a few times when it goes away for a little while. Please diagnose.

No where did I dsay all CEL problems can be diagnosed over the internet. Merely that some specialized CEL problems can. Maybe this is one of them, I'd suggest checking on Tahoe enthusists sites.
posted by Mitheral at 8:32 AM on March 20, 2012


(I hasten to add that lack of specificity in a question isn't a judgement on the asker; sometimes people fail to include detail they're able to, and that's a poor choice in framing, but a lot of the time people are relatively vague because they have no expertise either. I can ask a detailed question if something goes wrong with my guitar, but I only recently started driving and would probably be delighted if I figured out that the CEL was even what that little light on the dash was. Again: complicated problem.)
posted by cortex (staff) at 8:34 AM on March 20, 2012


The Torque app is pretty great, and has all sorts of gauges and dials that pair GPS and engine data. The developer releases regular updates and refinements as well.
posted by Burhanistan at 8:34 AM on March 20, 2012


I've actually seen some amazing answers to very technical questions here.
I think a certain level of obscurity is required. If you're specific enough, the subject matter experts jump in. If you're vague and get into the realm of user experience, you get buried.
posted by Stagger Lee at 8:35 AM on March 20, 2012 [2 favorites]


I have a 2001 Chevy Tahoe with a constant CEL for the past 3 years, except for a few times when it goes away for a little while. Please diagnose.

Holoprosencephaly. Probably you overdosed your truck on homeopathic remedies. Have you examined its testicles recently?
posted by ROU_Xenophobe at 8:40 AM on March 20, 2012 [1 favorite]


I think a certain level of obscurity is required. If you're specific enough, the subject matter experts jump in. If you're vague and get into the realm of user experience, you get buried.

Obscurity of the subject itself helps, too. I think that's why this is a particular problem with car questions. Cars are so common that lots of people have experiences of their own with them that they can bring into an answer.

If I asked why the master caution light in my 737 keeps lighting up, there probably wouldn't be a whole bunch of people answering with wild guesses based on their previous experiences with airliners.

Though that may also fall into the category of "if you need to ask that on the Internet, you probably shouldn't be in a position of needing to know it."

Anyway, it's pretty clear the right answer to the hill descent issue is to pull the fuse for the ABS and then lock up the brakes all the way down. This minimizes wear on the clutch AND the brakes, so it's a win-win solution.
posted by FishBike at 8:56 AM on March 20, 2012



Anyway, it's pretty clear the right answer to the hill descent issue is to pull the fuse for the ABS and then lock up the brakes all the way down. This minimizes wear on the clutch AND the brakes, so it's a win-win solution.
posted by FishBike at 8:56 AM on March 20 [+] [!]


Personally I always find it best to aim for a cyclist; if you do it just right their ten speed racing bike will get tangled in your wheel well and provide just enough drag to slow your car to a gentle stop. Try to hit them on the passenger side so that if the rider flips up and over your windshield they won't decrease your visibility.
posted by Stagger Lee at 9:07 AM on March 20, 2012


My car's leaking fluid. Is it safe to drink?
posted by one more dead town's last parade at 9:12 AM on March 20, 2012 [2 favorites]



My car's leaking fluid. Is it safe to drink?
posted by one more dead town's last parade at 9:12 AM on March 20 [+] [!]


Probably condensation from your AC unit, you should be fine as long as it isn't sweet.
posted by Stagger Lee at 9:17 AM on March 20, 2012


Dude, the primary outcome of this thread will be that from now on, forever and ever, people are going to randomly memail you all their car trouble questions, and they will get really huffy and offended when you do not answer each one with the careful in-depth discussion you have provided here.
posted by elizardbits at 9:22 AM on March 20, 2012 [3 favorites]


My car's leaking fluid. Is it safe to drink?

First you must answer: will it blend?
posted by bonehead at 9:22 AM on March 20, 2012


well done indeed.
posted by elizardbits at 9:22 AM on March 20, 2012


...people are going to randomly memail you all their car trouble questions...

Well, hopefully that takes some of the pressure off ottimo.
posted by griphus at 9:35 AM on March 20, 2012


Dude, the primary outcome of this thread will be that from now on, forever and ever, people are going to randomly memail you all their car trouble questions, and they will get really huffy and offended when you do not answer each one with the careful in-depth discussion you have provided here.

Or they could memail elizardbits about why Brockles isn't answering them in a timely fashiion.
posted by Brandon Blatcher at 9:39 AM on March 20, 2012




This is actually (at least) the second MeTa where Brockles has been held up as a car expert. (I wrote a song for the other one!)

I completely get why people react to threads like this with comments about how most Ask users don't read MeTa, so you're never going to change anything. But for those of us who do read these threads, it can have an impact, and one less person chiming in when they can't be of help is one less bit of noise. Before this thread was posted, I actually was about to type up a response to the Ask in question and stopped myself, realizing that my own CEL experience is really not relevant. This is largely due to people making pleas to be a bit more thoughtful about jumping into Asks about areas where whatever information you might have, if you even have any, is likely irrelevant.

AND BONUS! I totally ordered the ODB thing TomMelee linked above (I'd been considering getting something like that for a while now) and Prime will have it here on Thursday and a co-worker and I are just gonna GEEK RIGHT OUT over that + Torque when it gets here.
posted by SpiffyRob at 9:41 AM on March 20, 2012


Seriously though guys, while I have you all here, why is there a rheostat on the accelerator of my 71 Buick, and what color of wire do I need to connect to it? Is it a kickdown switch? Did the wire color change between the 71 harness and the 72? What if the harness came from a Centurion, will that make a difference?
posted by Stagger Lee at 9:51 AM on March 20, 2012


blatcher you bastard
posted by elizardbits at 9:58 AM on March 20, 2012 [2 favorites]


I totally ordered the ODB thing TomMelee linked above

Aw man. That is totally NOT the utterly awesome Ol Dirty Bastard-voiced car-trouble-analyzing AI that I was imagining.
posted by elizardbits at 10:00 AM on March 20, 2012 [8 favorites]


The CEL for your gas cap being loose once is pretty much the worst design choice ever. It just teaches people to ignore the CEL because it "goes away eventually". I think mine takes 10 starts or something to reset, which might be a week.
posted by smackfu at 10:09 AM on March 20, 2012


I have a basic rule on car questions to check and see if Brockles has answered. Because, if he has, nothing I add is going to add to the answer at that point.
posted by COD at 10:17 AM on March 20, 2012 [1 favorite]


The CEL for your gas cap being loose once is pretty much the worst design choice ever.

That depends on who you are designing for. If the goal is to get the user to ante up $85 to his dealer for a code check, then it's a brilliant bit of design.
posted by COD at 10:18 AM on March 20, 2012 [2 favorites]


This is a tall hill to climb, fella. No one seems to mind the horrifically bad medical and legal advice being dispensed on AskMe, so they're probably not going to fall over themselves to stop people from speculating about cars.
posted by Mayor West at 10:24 AM on March 20, 2012


That depends on who you are designing for.

It totally is stupid that minor faults are triggering the same kind of visible warning as relatively major ones. This is not, though, necessarily a money grabbing issue from car manufacturers.

Legislation demands that emissions systems are of high importance. I don't know for certain but it is very possible that any fault in an emissions system needs to be treated as 'requires prompt attention' by the manufacturer. In which case, the CEL is the right place to put that kind of 'response required' light.

No, it doesn't matter, but it may be an issue for manufacturers to explicitly state 'this problem is minor and can totally wait until your next pay cheque' through some other means (like low washer fluid, for instance, something of that kind of banality).

Yes, the CEL is stupid in its universality. It'd be great if OBD2 was more easily available, but there is a major danger in people with incomplete knowledge dicking around with something because they think a fault code tells them all they need to know. A more nuanced urgency escalation warning system would be good, but it isn't necessarily the manufacturers that are deciding where emissions related stuff (the fuel evap system that can trigger the fuel cap issue) sits in that importance scale.

Also: The fuel cap can be the cause of a CEL, but so can over-filling and leakage into the carbon canister during refueling. This will also eventually go away as the fuel evaporates, so it isn't always a fuel cap that is the cause of not only the CEL but also the very same fault code as the fuel cap will register.
posted by Brockles at 10:26 AM on March 20, 2012 [1 favorite]


It is like when a 2 year old starts crying

When mine did that, it was the oxygen sensor.
posted by flabdablet at 10:38 AM on March 20, 2012 [12 favorites]


elizardbits: "Aw man. That is totally NOT the utterly awesome Ol Dirty Bastard-voiced car-trouble-analyzing AI that I was imagining."

Really? The one I got accurately diagnosed the source of the shimmy shimmy ya in my steering and, once provided with a mic, took it away.
posted by stet at 10:39 AM on March 20, 2012 [7 favorites]



The CEL for your gas cap being loose once is pretty much the worst design choice ever. It just teaches people to ignore the CEL because it "goes away eventually". I think mine takes 10 starts or something to reset, which might be a week.

It would be advantageous if the computers were better at diagnosing the cause of faults. In some cases, this is possible, but mostly its not. For example, there are numerous faults that can cause that one error code :

Loose gas cap
Hole in the tank
Overfilled gas tank
Sensor fault
Bad fuel pressure pump
Plugged return line

The computer cannot distinguish between the banal error (gas cap) and the dangerous one (hole in the tank). The point is to get someone knowledgeable to check the entire system.
posted by Pogo_Fuzzybutt at 10:40 AM on March 20, 2012


Of course, most people don't even watch their oil pressure or temperature gauges.
posted by Stagger Lee at 10:42 AM on March 20, 2012


... or temperature gauges

You mean that's not the GPS gauge? "You're getting warmer... warmer... colder..."
posted by FishBike at 10:46 AM on March 20, 2012 [3 favorites]



You mean that's not the GPS gauge? "You're getting warmer... warmer... colder..."
posted by FishBike at 10:46 AM on March 20 [+] [!]


And when you're at your destination (red hot) the car will actually stop for you!
posted by Stagger Lee at 10:47 AM on March 20, 2012 [5 favorites]


Man, I don't know whether I should be more disappointed in my typo or in the fact that there is not, in fact, a Bluetooth ODB thing out there.

On the plus side, my attempts to find "bluetooth Ol Dirty Bastard" resulted in Google returning results for "bluetooth ODB", and they were many, so while I may be an idiot, at least I'm not a lonely one!
posted by SpiffyRob at 10:54 AM on March 20, 2012


But that's probably bad news for all you non-idiot smarty pantseses.
posted by SpiffyRob at 10:55 AM on March 20, 2012


Of course, most people don't even watch their oil pressure or temperature gauges.

I rented a Mazda 3 that had a "engine cold" light. Same as the overheated one but blue. That puzzled us for a bit, I'll tell you.
posted by smackfu at 11:01 AM on March 20, 2012 [1 favorite]


I rented a Mazda 3 that had a "engine cold" light. Same as the overheated one but blue. That puzzled us for a bit, I'll tell you.

A weird blue light came on in my Subaru so I looked it up in the owners manual. Low tire pressure! What a pain in the ass, now instead of ignoring my tires for months at a time I'll be forced to fill them up now and then just to make the stupid light go off.

Technology has ruined my life.
posted by bondcliff at 11:02 AM on March 20, 2012 [4 favorites]


Even better is that the tire pressure sensors will probably need replacing at least once during the normal life of the car. $75 for each wheel.
posted by Burhanistan at 11:07 AM on March 20, 2012


We do live in this fancy new digital age, why not have a directly informative error display in a car? The binary nature of the check engine light doesn't seem to make much sense anymore unless you're treating your car completely like a black box and you just want a single light to turn on telling you that it is time for repairs, and if you want that, why not just make it an option?

Is there a compelling reason to keep the CEL as is?
posted by sciencegeek at 11:10 AM on March 20, 2012


I was the asker on the question (please don't eviscerate me, y'all) and what was frustrating was that, I don't mind anecdotal, speculative answers from VW drivers - VW's are weird, occasionally wonderful, terrible beasts - but speculative answers from people with Mazdas.

If I wanted hardcore, OBD code specific advice, I'd go to a VW forum.
posted by ablazingsaddle at 11:16 AM on March 20, 2012 [2 favorites]


I think you are a great resource for car questions, Brockles, and also quite generally, for that matter; you've been a lot of places and seen a lot of interesting things-- and I want to hear about those things.

I disagreed with your answer that the engine braking in that specific situation-- 12 miles (IIRC) of nearly continuous downhill engine braking on the way home from a ski area-- would not cause greater engine wear than the same route not using engine braking, because I think the engine braking in that circumstance would produce more carbon deposits, and carbon deposits cause engine wear.

Cold engines make for more carbon deposits, and the OP mentioned (again, IIRC) that the engine didn't warm up for the entire 12 mi.-- a very unusual circumstance.

However, after gathering together my links and writing a proto-comment, I didn't post because I feel that I have a history of irritating you with my answers, and I don't want to contribute to any reduction in the frequency of your comments.
posted by jamjam at 11:20 AM on March 20, 2012 [1 favorite]


Cold engines make for more carbon deposits

Um. No engine with zero fuel being injected (as is the case during engine braking) will produce carbon deposits. None. No carbon deposits. Cold or otherwise. Hence no damage.
posted by Brockles at 11:24 AM on March 20, 2012


I don't get the hate for the check engine light. I guess you could have your car instrumented like an airliner cockpit, with a light or gage for every parameter. (Actually, with the bluetooth or wifi OBDC transducer and a laptop or several, you could do that on your own now.) That's not what I want. A few key gages, a warning light for the most urgent things, and one combined trouble light for everything else, with a code to tell you exactly what went out of spec.

It would be nice if the in-dash display could read the code itself and display the title so I wouldn't need a code reader, though. Maybe a check engine light with a scrolling "cooling system fault" so I would know I could keep driving, but to keep a sharp eye on the temp gage.
posted by ctmf at 11:25 AM on March 20, 2012


Brockles, unfortunately there is no fixing stupid. Move on, it's healthier for you.
posted by terrapin at 11:28 AM on March 20, 2012 [1 favorite]


with a code to tell you exactly what went out of spec.

"PC Load Oil? What the fuck does that mean?"
posted by bondcliff at 11:30 AM on March 20, 2012 [9 favorites]


Is there a compelling reason to keep the CEL as is?

Perhaps they can graduate to having a little screen that shows a bomb and "error type 11" or something.
posted by furiousthought at 11:30 AM on March 20, 2012


Even better is that the tire pressure sensors will probably need replacing at least once during the normal life of the car. $75 for each wheel.

And one in the spare. It's almost as if they want you to maintain your car or something.
posted by Pogo_Fuzzybutt at 11:32 AM on March 20, 2012


My car made a noise the other day. Should I stop drinking?
posted by Slap*Happy at 11:32 AM on March 20, 2012


I'm drinking. Am I a car?
posted by routergirl at 11:41 AM on March 20, 2012 [5 favorites]


<blink>[ MASTER WARNING ]</blink>
posted by odinsdream at 11:42 AM on March 20, 2012


...Of all the things I envisioned Metafilter crossing over with, Car Talk wasn't one of them.
posted by EmpressCallipygos at 11:47 AM on March 20, 2012


in the US you can take your car to auto zone, o'reilly's, and other such chain stores and they'll check your code for free.
posted by nadawi at 12:12 PM on March 20, 2012


What's the OBD code for a car that needs its anal glands expressing?
posted by ambrosen at 12:18 PM on March 20, 2012 [6 favorites]


Sometimes, AskMe is like Coinstar. A lot of stuff gets thrown into the machine, a lot of nickles and pennies and dimes that you don't want. Somewhere in all of the shifting and churning, though, you get the prize at the end -- a valuable receipt that you can exchange for a big bag of Cheetos.
posted by SpacemanStix at 12:22 PM on March 20, 2012


What's the OBD code for a car that needs its anal glands expressing?

That would be a #2
posted by JohnnyGunn at 12:27 PM on March 20, 2012 [2 favorites]


We do live in this fancy new digital age, why not have a directly informative error display in a car? The binary nature of the check engine light doesn't seem to make much sense anymore unless you're treating your car completely like a black box and you just want a single light to turn on telling you that it is time for repairs, and if you want that, why not just make it an option?

The CEL is mandated by law to alert you of things you can't tell otherwise by driving. EG: Your cat is malfunctioning and you are spewing CO and NOx into the air.

A directly informative information display can't be used for lock in and sadly would be seen as confusing by many drivers. See for example the PC Load Letter error joke above. PC Load Letter is an extremely clear error message for those who know what it means (The paper cassette requires paper and the printer is expecting letter sized paper in that cassette) but is a source of fustration and snide jokes from the ignorant.

PS: On many HP printers you can change the "Online" message to say whatever you want; it was a glorious day the April 1st when every printer in my building displayed "Low Coolant" instead.
posted by Mitheral at 12:28 PM on March 20, 2012 [4 favorites]


It's not the answers that are useless, it's the Check Engine light.

In my experience, 99% of the time, it lights up to let me know I'm almost due for scheduled maintenance -- "almost" meaning "not for another four months, but we'll tell you way too early so we can reset the thingy way too early and you come way more often than you need to and we make way more money."
posted by Sys Rq at 12:37 PM on March 20, 2012


We do live in this fancy new digital age, why not have a directly informative error display in a car?

I have this conversation every so often at work :

user : Something bad happened, and there was an error message, but I clicked it away and now it doesn't work.

Me : What did the error message say ?

user : I don't know. Do you think it was important ?

Me : ....
posted by Pogo_Fuzzybutt at 12:39 PM on March 20, 2012 [3 favorites]


+++ OUT OF PETROL ERROR ???? +++
+++ REDO FROM START +++
posted by EndsOfInvention at 12:44 PM on March 20, 2012


Is this simply a case of people getting their $5.00 worth? Paid to join, have no idea how to make a FPP, but want to comment even though they have only sketchy anecdotal knowledge of the AskMe topic. Too harsh?
posted by Cranberry at 12:45 PM on March 20, 2012


PS: On many HP printers you can change the "Online" message to say whatever you want; it was a glorious day the April 1st when every printer in my building displayed "Low Coolant" instead.

I will shamelessly steal this idea at the first opportunity. Unfortunately April 1 is Sunday this year and I will be on vacation anyway, so it will have to wait for 2013.
posted by TedW at 12:48 PM on March 20, 2012


Your cat is malfunctioning and you are spewing CO and NOx into the air.

Ain't that the truth. Son of a.
posted by kingbenny at 12:50 PM on March 20, 2012


Cold engines make for more carbon deposits

Um. No engine with zero fuel being injected (as is the case during engine braking) will produce carbon deposits. None. No carbon deposits. Cold or otherwise. Hence no damage.

Thank you for providing an example of the kind of link-free and dogmatic comment which often fails to even address the question at issue that has, in my opinion, been the major flaw in your contributions here.

Perhaps you'd care to glance over a long thread at ecomodder.com in which a number of members respond to the question How Does DFCO Work in Your Car?.

I was surprised at the wide variation in the reported conditions that were necessary to initiate Deceleration Fuel Fuel Cut Off. Of particular interest, for the situation of the original question:
In my Mustang, DFCO only works after the coolant temperature has reached ~150°F. Then it will DFCO down to about 1500 RPM. With cruise control engaged, it will DFCO down to ~1000 RPM. Tapping the cruise control down is a great way to shed speed for a lower speed limit zone.
and
The DFCO for the Vibe usually works between about 40 and 65 mph, once the engine is at least partially warmed up.

If I have the A/C on, DFCO is a bit more hesitant to engage, and has a range closer to 50-60 mph.

It's very handy on the highways and non-trafficky parts of town.
implying that the OP could have have gotten quite a bit of fuel into his cold engine on that long, chilly deceleration, depending on the mechanism used by his car.

But even if his DFCO works perfectly, a twelve mile trip in typical apres-ski traffic would involve quite a few accelerations just to maintain spacing and constant speed, unless the OP was comfortable generating back-ups of hundreds of cars by the end, and those accelerations, too, would mean fuel in a cold engine.
posted by jamjam at 12:52 PM on March 20, 2012 [1 favorite]


I realize MeTa has historically been a pretty open playground, but in a case where a moderator is actually saying that this could be a helpful thread for future AskMe questions, maybe we could do with a bit less of the "Should I stop drinking?" and "Am I a car?" nonsense.
posted by cribcage at 1:09 PM on March 20, 2012


"Should I stop drinking?" and "Am I a car?" nonsense.

Hey, that's my wife you're talking about. She gets a free pass as far as I am concerned. You should see the shit she was giving me in email...
posted by Brockles at 1:11 PM on March 20, 2012 [2 favorites]


in the US you can take your car to auto zone, o'reilly's, and other such chain stores and they'll check your code for free.

Not in California. There was a lawsuit over this and it was ruled that (from what I remember) this was construed as "practicing repair" which they are not allowed to do. Someplaces do have one you can buy and turn around and return after using. Not a "rental" though.

And yeah, anyone hating on the CEL - as someone who's pretty handy with vehicle repairs and who has owned some old cars without them, they are really handy. Read code, google code, buy new o2 sensor, install. Versus playing the old "well I replaced this part and that didn't fix it, what else can I replace" game.
posted by Big_B at 1:13 PM on March 20, 2012 [1 favorite]


@ Big_B: Ah, it's a California-only thing.
posted by ablazingsaddle at 1:14 PM on March 20, 2012


Actually, Brockles is wrong here - as mentioned above, if the CEL blinks at certain rates while the engine is running it indicates misfire or catalyst damage, which can be useful for diagnosing problems.

It is also useful for diagnosing problems if the CEL comes on during certain repeated driving conditions.

It is even more useful for diagnosing problems on older OBD1 cars because on many of them you can ground 2 terminals on the ALDL connector and the CEL will flash out diagnostic code numbers.
posted by rfs at 1:33 PM on March 20, 2012


Dont Drive like my Metafilter Spouse!
posted by wheelieman at 1:34 PM on March 20, 2012 [1 favorite]


implying that the OP could have have gotten quite a bit of fuel into his cold engine on that long, chilly deceleration, depending on the mechanism used by his car.

It still wasn't being burnt, so there's still no likelihood of carbon deposits being formed through incomplete combustion. It's not relevant to what we were talking about so your assertion that more carbon deposits will form in a decellerating engine is patently false - I note you didn't link to anything to support that claim, incidentally. Is that what you call being 'link free and dogmatic'? There is no combustion on decel. In most cars in anything other than the hypermiling edge case of slight decel as a means to save fuel while not losing speed, decel will be zero fuel. Hypermiling is not engine braking and pressures and loads created by the engine slowing the car is one of the parameters that the system uses to decide whether to fuel or not. If you have minimal pressure differential across the engine it assumes you may be about to go back on throttle and starts injecting. Hypermilers can sometimes sit in that band (usually a transitional state in normal driving) where they want to shut the throttle but not slow and the ECU is programmed to allow decent throttle response in that condition for when they reapply throttle (so must have fuel ready).

You need both fuel and combustion to create carbon deposits and at least one of which is not present in decel. Usually neither are present in any significant decel (which just as many of the comments in the link you point to supports, including one from a manufacturer that is identical to that of the original askme that fully supports my assertion).

Essentially, you are taking a concept - that of carbon deposits forming from combustion in a cold engine - and applying it to 'long time being cold = long time making bad deposits' which is simply not true. The main time those deposits form will be under acceleration or steady state running until the car is warm. The car takes a certain amount of steady state running or acceleration to get to being warm. Until it is warm, the thermostat is pretty much shut so no water is flowing through the radiator and so the car doesn't cool back down beyond that of airflow over the block (not much effect) and the car will warm at a similar rate in proportion to fuel burn, but a slower rate overall due to less fuel burn generally. If there is a longer period of burn at a lower temperature it will be very, very slight. Thus carbon deposits are not an issue.

Incidentally, I didn't at any stage suggest it wouldn't cause any more wear during that cold period - maybe you missed that bit. That extra wear will be due to running at lower temperatures for longer and be caused by the implications of the cold temps on friction and oil delivery, primarily not due to non-existent extra carbon deposits or from some mythical evil of 'engine braking = bad' which people often suggest on here.
posted by Brockles at 1:35 PM on March 20, 2012 [1 favorite]


Brockles is wrong here - as mentioned above, if the CEL blinks at certain rates while the engine is running it indicates misfire or catalyst damage, which can be useful for diagnosing problems.

It is also useful for diagnosing problems if the CEL comes on during certain repeated driving conditions.


Um. That completely supports my point, actually. The CEL is not sufficient information to equal a specific fault. You need consistent driving conditions to cause it or blinking or some other parameter. My issue is that 'CEL light is on' is sufficiently vague with no other info that people assume it means 2 or even 4 different things so their own experience is helpful.

Like Mitheral above, people that apply other parameters as part of the CEL observation aren't really the issue. It looks like people like you don't even know you do it automatically so don't notice that some people assume CEL = Gas cap or otherwise. There are always extra parameters you need.
posted by Brockles at 1:38 PM on March 20, 2012 [1 favorite]


I think my car manual says that if the CEL is blinking, you should pull over and get a tow.
posted by smackfu at 2:33 PM on March 20, 2012


It's amazing how many parallels this issue has to health-related AskMes that elicit suggestions for homeopathic and other bullshit remedies. When you post actual links to actual evidence, the evidence gets deleted and the bullshit stands.

This is a very superstitious crowd.

Good luck, Brockles.
posted by klanawa at 3:48 PM on March 20, 2012 [1 favorite]


When you post actual links to actual evidence, the evidence gets deleted

I stopped reading and participating in Ask after some really obnoxious behaviour there, but I find it extremely difficult to believe that this happens.
posted by PareidoliaticBoy at 3:54 PM on March 20, 2012


Burhanistan: "Downshifting is kind of a dance anyway. For most daily circumstances you shouldn't downshift to where the revs would spike in the next lower gear, but rather when it is in the middle or lower speed range of a particular gear. That way, you'll have enough torque if you need to accelerate again."

Exactly - you should be in the gear that is appropriate for your current speed. Modern cars don't really need engine braking because the brakes are so good anyway, but it doesn't do your car particular harm either way if you want to do it - both clutches and brakes are wear items and will need replacing regularly no matter what you do.

jessamyn [star]: "I had at least three mechanics tell me the check engine light in a Subaru Forrester just comes on all the time and it's best ignored.

I used to have a Holden Commodore and they have a known issue with the seat belt pre-tensioners triggering the light that tells you the ABS has malfunctioned. I think I got the mechanic to re-set it at about every third service and just got used to driving with it on in the meantime.

Brockles is right that people often chime in with more-or-less useless information about automotive questions (I'm sure I've done it at least once), but that is the case with all questions because people want to help and they are doing their best. Regardless of the question type, you asks your question and you takes your chances - it's up to each individual to decide how useful the information is. Free advice is usually worth what you paid for it.
posted by dg at 4:01 PM on March 20, 2012 [1 favorite]


My opinion of the usefulness of folks' AskMe answers is usually directly proportional to how much I already know about the subject.
posted by box at 4:27 PM on March 20, 2012 [2 favorites]


PareidoliaticBoy: "I stopped reading and participating in Ask after some really obnoxious behaviour there, but I find it extremely difficult to believe that this happens."

Happened to me. Can't prove, obviously.
posted by klanawa at 4:32 PM on March 20, 2012


Haven't been here long so I know my opinion means jack and shit, but the car questions without the year, make, and model of car are begging to be skipped over. Don't feel like coaxing out that information from the asker. If you can't take the time to look outside and look at the badges, why would somebody bother to answer your question? This is coming dangerous close to a pun, but it seems most car repair questions are hit and runs.
posted by narcoleptic at 4:33 PM on March 20, 2012


What box said times a million. Now you know how I feel about publishing questions, Brockles.
posted by Sidhedevil at 4:59 PM on March 20, 2012


i just want to say that my check engine light's been on for 3 damned years and i have no idea why

i guess if it was important the damned thing would stop running
posted by pyramid termite at 5:14 PM on March 20, 2012


it may help at least to keep in mind that this kind of amplifying phenomenon is what's driving it, rather than people just being bloodyminded for no reason.


This vagueness spiral that you've alluded to - is sadly not what's driving ( boom boom !) many of the askme answers.

that is the case with all questions because people want to help and they are doing their best.

No, that's not it either.

If you think askme is about providing actual proper answers, you're sadly mistaken - it's about page views, page hits and all that kind of thing. Answers have absolutely nothing to do with it.
posted by sgt.serenity at 5:15 PM on March 20, 2012


it's about page views, page hits and all that kind of thing.

Can you clarify? If you're suggesting how we mod askme or any other part of the site is driven by a concern for maximizing traffic or monetization or something like that, you are deeply wrong.
posted by cortex (staff) at 5:24 PM on March 20, 2012 [1 favorite]


Aw shit, the jig's up.
posted by Alvy Ampersand at 5:46 PM on March 20, 2012 [2 favorites]


I think we should hire Brockles to be on call for ALL automotive questions. He could have his own Brockles Beacon and everything.

So...if my 2000 passat wagon, 1.8t, occasionally, like once every couple of weeks spews out a medium sized cloud of white smoke, do I need to get my engine rebuilt, change the rings and head gasket, or is it just my catalytic converter going bad?

Not really looking for an answer, but I bet Brockles is the only one here who REALLY KNOWS MAN! Seriously.

(If anyone want to try, that's cool, but I already know the answer.)
posted by snsranch at 5:54 PM on March 20, 2012


The answer is you bought a 2000 VW Passat. It's like buying Satan and trying to diagnose why your daughter's levitating over her bed.
posted by Slap*Happy at 6:12 PM on March 20, 2012 [2 favorites]


cortex: "it's about page views, page hits and all that kind of thing.
Can you clarify?...


Don't feed the trolls!
posted by dg at 7:05 PM on March 20, 2012


Brockles' concern here is strange to me. Why, really, do you care? Like many or most realms of human endeavor, lots of people want to say their piece -- it's kind of a human need, to say your piece -- and most of what is said won't be on point. Who cares? People who are looking for answers know to disregard a lot of answers. Everyone knows this.

I just find it odd that you care so much.

And as to Sgt. Serenity's point that you're naive if you think AskMe is about providing good answers... Wow. That's just obviously wrong, and a crazy, rude slap at moderators who, I think, are almost TOO vigilant in making it only about good answers.
posted by jayder at 7:08 PM on March 20, 2012 [2 favorites]


I just find it odd that you care so much.

Think of something that you know a whole shit ton about.
Imagine seeing a question related to it, and knowing that you can help.
Imagine opening the question and seeing a whole shit ton of incorrect information.
Then imagine you attempt to correct them (or god bless your soul flag them), and no one listens.

It's frustrating, and it decreases the utility of AskMe on a massive, basic level.
posted by Big_B at 7:41 PM on March 20, 2012 [2 favorites]


sgt.serenity said:
"it's about page views, page hits and all that kind of thing. Answers have absolutely nothing to do with it."

What a strange and cynical disconnect. I know I shouldn't do it, but it kind of makes me feel sorry for you, which then makes me feel bad for such a patronising response to something so sad and odd.
posted by batmonkey at 7:56 PM on March 20, 2012


Nah. I'd just write an extra line about my credential for knowing the right answer along with the right answer. Then it's up to the asker to judge/research further. Just like real life. Not my job to get emotionally involved in getting the glory of being right. (but that's nice, too)
posted by ctmf at 7:59 PM on March 20, 2012 [3 favorites]


I'm a hobbyist and an amateur, but I know a little bit about cars. I build fuel injection systems in my spare time, and love talking about things like the interplay of the various subsystems. I can talk intelligently about the composition of clutches, what causes carbon buildup in an engine and where it happens, for example. Basically, I'm a huge nerd, and that informs the depth with which I attempt (and, frankly, succeed) at understanding the engineering the underlies automotive design. I lack the breadth of experience that Brockles has, however.

I have two basic rules when it comes to threads about cars on AskMe:
1) If Brockles has commented, think very hard about whether I have anything to add
2) Don't wade in if the thread is already full of unfounded conjecture

The issues Brockles brings up have a direct effect on how and whether I contribute. I think his intentions are good and his conclusions are sound, and I encourage people to heed his advice as though he were a greasy ikkyu2.
posted by TheNewWazoo at 8:04 PM on March 20, 2012 [2 favorites]


Big_B:

I have my own little area of knowledge, law, where even I wax expert on things I probably should be talking about. And yes, it annoys me when people say "I'm not a lawyer, but [blanket statement about law that is wrong]." I call them on it, sometimes. But I never really think you can stamp that out, because people want to say their piece.

I have been in a bind a time or two, needing to throw a question out to a bunch of lawyers, and I've THOUGHT about posting it here, saying "MeFi lawyers, have you ever encountered [obscure legal issue]? Do you have any cites?" and then asking only lawyers to answer. I've never done it because I think it's kind of tacky to limit a question that way, and it seems tacky to use MeFi for legal research. BUT if I did it, I feel CERTAIN that non lawyers would answer it, and really who can blame them? We're all volunteers here, nobody is checking credentials, and I don't think a question asker on a site like this should be able to delimit the expertise of the answerers. Your participation here is basically free (for those of us in the developed world)... Or, well, the price of a sandwich. And for that price, I just think you give up any expectation that answerers will restrain themselves from giving the question a shot, regardless of their expertise. This is a casual, laid back type of free for all, limited by minimal norms of relevance and civility. To expect more than that is to care too much.
posted by jayder at 8:08 PM on March 20, 2012


probably should not be talking about
posted by jayder at 8:09 PM on March 20, 2012


I am disappointed that my car has not got a “Check ‘Check Engine Light’” light. 'Cos, y'know, it could fail — and then where would you be?
posted by scruss at 8:10 PM on March 20, 2012 [1 favorite]


A small piece of black electrical tape will cover the Check Engine Light and alleviate the problem.
posted by fieldtrip at 9:31 PM on March 20, 2012 [1 favorite]


"Maybe if you have a high end racing car, but most econboxes wouldn't work that way."

Even back in the day, when I was still young and there were quite a few manual transmissions around, most people had no clue about this.

But, in most cars, at least back then, there's nothing stopping you from changing gears without the clutch when you've got the engine and the drivetrain synced. In fact, aside from just learning your revs intuitively from lots of experience, once you move to neutral you can usually feel the resistance to moving into another gear decrease to nothing as you approach the correct engine RPM. It's a good way to get a sense of what a given speed corresponds to a certain engine rev in a certain gear...other than just paying attention in general, of course.

Anyway, yeah, once the vehicle is moving you can drive and shift without using the clutch if you know what you're doing. I recall driving around a couple of days without using the clutch except when starting and stopping just for the hell of it.

This also applies to the whole downshifting and engine-braking argument. It's how you're downshifting and engine-braking that will make a difference whether you're creating more or less wear. If you bring the revs up while the clutch is disengaged, engage it, and then let the engine do the braking without there being much of a mismatch and unnecessary abrasion, then you won't be causing much, if any, wear. If the revs and gear are mismatched and you engage the clutch at leisure, then, yeah, you're unnecessarily causing wear...just as you might be doing when you are accelerating, as well.

And Cecil Adams is a bit off when he gives the impression that downshifting and such is all just for fun. That's totally not true. It's hard to explain to anyone who doesn't already know, but using a manual transmission and clutch for all the things that are possible give the driver a big increase in control of the vehicle. Which isn't necessarily a good thing, if the driver misuses or doesn't understand that control. But if you have an intuitive feel for it, driving an automatic compared to a manual is halfway like letting someone else do part of the driving. If it didn't hurt my hips because of my bone disease to use a clutch these days, I don't think I'd ever drive an automatic by choice, ever. Cars are just not much fun to drive these days. But then I'm old.
posted by Ivan Fyodorovich at 10:04 PM on March 20, 2012 [2 favorites]


Perhaps you'd care to glance over a long thread at ecomodder.com in which a number of members respond to the question How Does DFCO Work in Your Car?.

Awesome. I drive the Sentra SE-R described. So when I downshift 5-4-2 bringing the revs back up to 3500 each time I'm actually saving more fuel than coasting down from 2200rpm@40-45mph.
posted by Talez at 11:44 PM on March 20, 2012


> You don't need to clutch to shift.

Maybe if you have a high end racing car, but most econboxes wouldn't work that way.


My 2008 Nissan Versa*, 2004 Nissan SE-R SpecV and 2001 Nissan GXE would all like to have a word with you about that.

*this car was particularly easy to drive without a clutch, so much so that it actually stopped being fun because it was like working the HVAC controls
posted by davejay at 1:13 AM on March 21, 2012


It's hard to explain to anyone who doesn't already know, but using a manual transmission and clutch for all the things that are possible give the driver a big increase in control of the vehicle.

Such an understatement. Remember all those accidents caused by floor mats catching gas pedals, causing the pedal to stay down? That happened to me once, but my car was a manual transmission, so by the time I noticed the engine was still revving from a floormat-stuck pedal, I had already clutched in because I was shifting gears at the time. Total non-event, and I'm grateful for it.
posted by davejay at 1:15 AM on March 21, 2012


AskMeFi: YANAL, YANAD, but my cat now has a weird bump on her tail sustained after she drove my car into a plate of beans that my annoying neighbor who plays music ALL NIGHT LONG left on our shared driveway. She then announced her plans to marry after three dates with a tomcat she met on OK Cupid. Should I worry or sue her for damage to the tires? And can I eat the beans?
posted by kinetic at 3:21 AM on March 21, 2012


So Brockles, are you related to or named after Peter Brock?
posted by taff at 5:30 AM on March 21, 2012


"I stopped reading and participating in Ask after some really obnoxious behaviour there, but I find it extremely difficult to believe that this happens."

Happened to me. Can't prove, obviously.


Whoa. Dude. Speaking as one of a handful of cranks-with-a-hobbyhorse about how medical and legal questions get handled on AskMe, let me just say: this doesn't happen. Ever. For whatever quibbles we might have with how the community acts in those threads, the mods here are incredibly even-handed in how they handle answers in AskMe.

What HAS been known to happen, on rare occasions, is that someone posts a woo-woo answer, and immediately gets piled on by a bunch of people who are basically yelling at him for posting bullshit. Those get deleted. Rightfully. Because they're noise, and aren't answering the question. But I have never once seen a respectfully-worded "I think you're wrong, and here's a link to evidence to support that position" answer removed here, and there's flat-out no chance that your answers are being double-secret-deleted to game PageRank.
posted by Mayor West at 5:35 AM on March 21, 2012 [2 favorites]


are you related to or named after Peter Brock?

Nope. I know who he was, but no link.

Clutchless shifting:
I once drove a Van Hool Bus converted to a hospitality unit across half of England with no clutch. It crapped out on the way to support a Rally event and after tinkering with it at the event with no joy, we decided to wait until traffic died to just drive it home. It was actually great fun. Start it in 1st gear so it lurched along until it fired, and then just give yourself plenty of room so you don't need to stop again until you get back. 200 miles and no clutch in the dark on twisty English roads. It's shocking how much further ahead you have to think, even in a bus that needs some planning anyway, when you take longer to change gears and have to make sure you're in the right one ahead of time.

Really enjoyed it.

Not so much fun was the same bus on the way to the Isle of Man Ferry as I neared Liverpool in the pouring rain. I noticed the wipers were looking funny, and as I looked one slipped and they jammed together in the middle of the screen. Vertical 8 foot high windows are not good for visibility with ni wipers and crazy rain. I made the hard shoulder completely blind, fortunately, and had to fix it in the pissing rain.
posted by Brockles at 5:40 AM on March 21, 2012 [3 favorites]


So many of these requests boil down to "please don't answer questions where you think you know the answers but you really don't." Um, good luck with that?
posted by smackfu at 5:44 AM on March 21, 2012 [1 favorite]


Happened to me. Can't prove, obviously.

We'd be happy to reproduce the comment tat was deleted. It wasn't that you linked to evidence that arnica gel doesn't work for bruising, it was that you started a side derail about homeopathy being ineffective [not disagreeing, just saying it wasn't the topic of the thread] that didn't address the OPs question and was looking like it was going to make the thread go all sideways. I figured that would be obvious but obviously it wasn't. Sorry about that.
posted by jessamyn (staff) at 6:49 AM on March 21, 2012 [2 favorites]


Obviously the answer to "why is my check engine light on?" in any situation is "take it to a certified mechanic and have her/him pull up a code on the computer." The answer is almost always definitively available for a price.

Reminds me of so many medical questions, which I hate, because the only right answer is "go to your doctor and get checked," and the rest is almost always noise.

Often the reason someone doesn't want to go to a mechanic (doctor, computer technician, vet) is to save money. So the secondary answer in most cases is "sorry it costs money to live, but it could cost you much more than money not to have this professionally checked."
posted by spitbull at 7:08 AM on March 21, 2012


Love is like an oil change,
It's something that everyone needs.

Without it we lose all our bearings,
Just pull out your dipstick and see!

posted by Juffo-Wup at 7:14 AM on March 21, 2012



My opinion of the usefulness of folks' AskMe answers is usually directly proportional to how much I already know about the subject.
posted by box at 4:27 PM on March 20 [1 favorite +] [!]


It's like Wikipedia. If you're ignorant on a subject, it seems to be a wealth of useful information.

If you're a subject matter expert, it's suddenly embarrassingly and dangerously inaccurate.

What really worries me is that I might be learning something from all this! :)
posted by Stagger Lee at 8:08 AM on March 21, 2012


Perhaps it's just me, but I wouldn't post a CEL question expecting someone "qualified" or not would actually be able to diagnose the situation with much degree of accuracy.

If I was unaware of what the light even meant, though, I think it would be helpful to get a few comments regarding the Fuel Cap trick, just to try out a possible, though perhaps unlikely fix to the situation. It's the same when you call Apple Support, and they ask if you have zapped the PRAM or reseated the RAM or battery. It almost never is the cause of the problem, but it's an easy enough fix for anyone to do, that it makes sense to try it just to see.

I would personally ask (and I have) YANML (AL), YANMD (AD) type questions just to see if someone can offer me some knowledge or experience-based advice that would offer me some comfort in an otherwise scary situation, and take the answers as an overall barometer of perhaps how serious it may be. If I am completely unfamiliar with the situation and unsure of what to do, but nearly all the responses are pleading with me to get to the doctor ASAP or such, well, I'd probably go. In those matters, sure, I would have preferred to sit down with a qualified professional who could accurately evaluate my personal crisis and offer a solution, but not having the money to do so prevents me from doing that. A "shot in the dark" question is in the hopes that I would get some direction to head in with my own research, and perhaps just get a place to start.

Basically, a little peace of mind from people who have been in similar situations and came through relatively unscathed, whether or not it was just a gas cap, or a thousand dollar problem, can really help me out, as my brain tends to assume the worst, and if I did not know what a CEL was, I may have visions of fire, explosions, and death. It's nice to know that it could be something as simple as a gas cap... or a very expensive repair, and only an expert should make that determination. It helps to keep me off the ledge of instant crisis mode, and take a little time to think about where I want to bring my car depending on its symptoms, instead of panicking and going simply to the closest shop. Also, even given if it could be a super expensive repair, it assists me into putting things into perspective, and although it may be the catastrophe of the day to me now, the fact that some people have had this happen to them and still are able to post comments on AskMe and afford things like computers, internet service, and/or mobile phones reminds me that perhaps it's not the end of everything as I know it.
posted by Debaser626 at 8:49 AM on March 21, 2012 [4 favorites]


Here's the problem with my check engine light.
It goes on, I go to the dealer. He checks everything, there's nothing wrong. He then advises me to always tighten my gas cap for at least four clicks, and wants to charge me $70 to turn the light off.
As if I'm going to fall for a scam like that.
I drive with the light on. If something is wrong with my engine, it will become obvious soon enough, and without that stupid little money-grubbing light telling me so.
/rant
posted by SLC Mom at 9:08 AM on March 21, 2012


Plus, the only time a code ever diagnosed anything on my car the CEL did NOT come on early enough to be of any use and I needed to spend 3K to have the problem fixed. It coulda been 3K plus 70, so that is good.
posted by SLC Mom at 9:14 AM on March 21, 2012


SLC Mom, your anecdotes are exactly the sort of thing Brockles is complaining about, and that harms discussions regarding car problems. Modern (OBDII) cars are complex, and the computer systems that are used to diagnose them are scarily accurate, especially when you go beyond the basic federally-mandated systems. Encouraging someone to ignore a check engine light is bad advice.

There is no scam. There is no conspiracy. There is a huge and free market of diagnosticians, and you are free to go to the dealer, or not. You are free to do what you will regarding your own check engine light. But dragging out the dealer-as-scammer trope and encouraging someone to increase their risk of monetary loss because you have ignored your CEL while not understanding its underlying cause is detrimental to AskMe.

I'm sorry if that sounded harshly personal; I don't mean it to be so, but you've given us a textbook example of the problem. :)
posted by TheNewWazoo at 9:26 AM on March 21, 2012 [9 favorites]


I don't mean it to be so, but you've given us a textbook example of the problem. :)

Without a doubt, you're right in the sense of the MeTa post, but SLC Mom does bring into play some of the valid issues with the CEL light in general.


The problem is not just these types personal anecdotes, but also the fact that the way this issue is charged for out of warranty cars, that people have these anecdotes to tell.

Maybe it's my own confirmation bias, but I personally have owned two cars with false CEL warning issues, and have had friends with 3 others. In 10 years of driving, I have never personally witnessed a situation with a CEL warning indicating anything other than the same emissions oriented malarkey, either in a car owned by me or people I know. I don't work in the mechanics field, but I wish I could see the statistics of CEL warnings with regards to "non-issue" emissions type stuff versus serious problems.
posted by Debaser626 at 9:52 AM on March 21, 2012


Wazoo: I'm sharing my experience, in MeTa, not dragging out a trope, and definitely not making recommendations in AskMe. I'm also acknowledging that I am ranting about it. Brockles information is actually very informative, but it does not mesh with my experience in the real world.
posted by SLC Mom at 9:58 AM on March 21, 2012


Here's the problem with my check engine light.
It goes on, I go to the dealer. He checks everything, there's nothing wrong. He then advises me to always tighten my gas cap for at least four clicks, and wants to charge me $70 to turn the light off.
As if I'm going to fall for a scam like that.
I drive with the light on. If something is wrong with my engine, it will become obvious soon enough, and without that stupid little money-grubbing light telling me so.
/rant


The problem is that there are numerous faults that can cause that one error code :

Loose gas cap
Hole in the tank
Overfilled gas tank
Sensor fault
Bad fuel pressure pump
Plugged return line
etc.

The computer cannot distinguish between the simple error (gas cap) and the dangerous one (hole in the tank). The point is to get someone knowledgeable to check the entire system.

Users of complex systems do best with simple warnings. The professionals know where to look for more information. If you give a user information that a professional would use, you will only confuse and anger them - for example "Illegal Operation Error".
posted by Pogo_Fuzzybutt at 10:31 AM on March 21, 2012


Brockles information is actually very informative, but it does not mesh with my experience in the real world.

The real world.... Hmmm. Maybe change that to 'one instance of the Check Engine Light being illuminated'. That is not 'what happens in the real world' that is 'what happened to SLC Mom in one possible outcome of having the CEL illuminated'. Using anecdotal evidence of one outcome of many possibles to try and conclude that the entire concept is flawed and a money-earner for the dealership. TheNewWazoo is completely right and you have pretty much missed the point of this entire thread (I acknowledge the rant aspect) while at the same time perfectly pinpointed the main flaw of the CEL system while at the same time actively perpetuating the myth that the CEL is no big deal and that your experience can be used to judge it.

That is wrong. The ONLY way that you had any idea whether that fault was going to cause your car to explode into a blazing fireball or carry on for the next 20,000 miles perfectly fine is because you had someone check it. If a competent person reads the ECU fault codes and counsels ignoring it, then I am absolutely fine with people ignoring it. There will be a significant number of people that can do precisely that - some CEL faults are related to issues like emissions that are not real world issues and don't matter at all to a lot of us. So any emissions codes can be ignored by the user with no danger to their car.

Now the issue with the CEL light system as a whole is that it doesn't have any granularity between "this is pushing a bit more CO2 and particulates out than normal and maybe affecting fuel consumption" and "your engine is running in a manner that will cause an imminent and expensive failure if let unattended". Both issues produce a yellow light and force you to get it checked - not just in order to get it repaired, but also to allow you to have the peace of mind to ignore it.

However, now you are ignoring your CEL, a very complex and useful system of early warning is not available to you, so by dismissing the system you are preventing it actually doing anything good. Which is stupid that the CEL forces you to do that.

Now, don't get me wrong, both of my cars have the Check engine light on constantly. They stay on because there are things wrong with it that we haven't managed to pin down yet - intermittent faults are occurring that the ECU is picking up that WILL cause me a roadside failure at some stage but that we are unable to replicate in the shop at the moment - the system is by no means without flaws. I know something is going on, and I keep checking it with a small hand scanner and the big, fancy $5000 scanner and we've been through it a few times. So I do understand that sometimes, the damn thing is telling you something is wrong where the car will be perfectly fine. However, it also told me about an O2 sensor that would have caused me to fail an emissions test, told me about a transmission fault that meant I saved around $4000 on a smaller pre-emptive repair instead of a new transmission and also allowed me to spot a throttle body failure early enough that I could schedule a reconditioned part from the US for $600 around my work week rather than spend $1800 on a new one when it dumped me by the side of the road with limp home mode (15 kph at most for a 300km journey? NO thanks).

The CEL system is far too complex and capable to do without it. But it is still a bit too simple and limited to not give false positives. But false positives that cost (at most $70 - there are cheaper ways of doing it) is a better solution than no check system as manual diagnosis is impossible in a modern car for many repairs. The CEL gets a lot of bad press, but it is still a good and valuable system. It just needs to be smarter.
posted by Brockles at 10:31 AM on March 21, 2012 [7 favorites]




I appreciate Brockles's points, but I can't help wondering...

(1) Who does Brockles like for F1 champ this year?
(2) Who, if anyone, has the best claim to "morally" deserve a great season this year, and why?
posted by ROU_Xenophobe at 11:02 AM on March 21, 2012


Thank you Brockles. You have a great way of illuminating the multiple aspects of the problem.
To be fair, and to be a little less ranty, I'll add that I have actually been in to the dealer multiple times for the CEL, usually combining it with a routine maintenance visit. And have not been charged for any resets since that initial problem. But I was paying for other work. I have had it come on in combo with electronic failures and limped in to the dealer -3 times, IIRC- only to have the problem self correct and be undiagnosable. That problem stopped recurring after a factory recall re-sealed a battery.
Sadly, the light itself has never led to information which helped me help my car in any way.
I do NOT answer AskMe questions about cars. I ask them!
posted by SLC Mom at 11:03 AM on March 21, 2012


I love that sink. The foot pedal taps are a nice touch.
posted by bonehead at 11:26 AM on March 21, 2012


The drain is above the bottom of the basin, there is no plug mechanism, only a bachelor with a housekeeper would like such a sink.
posted by Meatbomb at 11:46 AM on March 21, 2012


Yeah, washing boogers and whisker shavings and other disgusting bits that normally go down bathroom sinks would be a unwelcome challenge.
posted by Burhanistan at 11:50 AM on March 21, 2012


The drain is above the bottom of the basin, there is no plug mechanism, only a bachelor with a housekeeper would like such a sink.

Impractical sink is impractical?
posted by odinsdream at 12:08 PM on March 21, 2012


I'm glad Brockles was able to answer the current auto question on Ask before anyone else, just in case, upon seeing it, we were overwhelmed by the urge to jokingly snark a "this exact same thing happened to me [except once the details were revealed totally not at all]" fake reply.

(And by 'we', I mean 'I', I suppose.)
posted by MCMikeNamara at 12:16 PM on March 21, 2012


The drain is above the bottom of the basin, there is no plug mechanism, only a bachelor with a housekeeper would like such a sink.

There could be holes drilled in the bearing housing under the grate and a plug mechanism could be remote. Also it kind looks like the washroom is of the sort that you could just hose down every day.
posted by Mitheral at 12:21 PM on March 21, 2012


(1) Who does Brockles like for F1 champ this year?

Not really a huge fan of F1, but it's hard to ignore. I think it is way, ay too soon to tell who will dominate this year. With so little testing available, teams don't get any kind of development momentum or cohesion of design until a few race sin unless they have a spectacular car. No-one seems to have that yet. The usual suspects (anyone in a McLaren or a Red Bull) are favourites from where I am sitting, but that's a boring and safe bet.

(2) Who, if anyone, has the best claim to "morally" deserve a great season this year, and why?

No-one. Never. There is no such thing as a 'morally deserving' racing driver or team. You get precisely what you pay for and for how hard you work.

It'd be nice to see Kimi show what he can do. I strongly feel that his tailing off of speed before his retirement was just as a direct result of motivation loss and there is a very real chance he will upset some regulars with his pace. His will be a comeback that makes Schumacher look a bit daft, I think.

But then I've always been impressed with Kimi. I was one of the Race Engineers stood on the pit wall at Donington Park when he was 17 and in his (fourth, I think) proper race car event (1999 Formula Renault Winter Series). I was friends with the Engineer on Kimi's team and as we all stood there with our mouths open as Kimi utterly and ruthlessly destroyed the field in damp conditions, every single one of us knew he was F1 material and more. The guy is phenomenal. In a 10 lap race, Kimi jumped into the car and was 40 seconds ahead of everyone, including regular season championship drivers. It was just ridiculous. It was Kimi ...(40 second gap - half a lap nearly)...then everyone else all in one big pack covered by about 20 seconds. Just stunning to watch. Kimi's engineer was just slowly shaking his head and smiling in a kind of bemused manner.
posted by Brockles at 12:23 PM on March 21, 2012


I haven't bothered to read all 185 answers so far, but have you checked to make sure your gas cap is tight?
posted by caddis at 1:28 PM on March 21, 2012 [1 favorite]


"Now the issue with the CEL light system as a whole is that it doesn't have any granularity between 'this is pushing a bit more CO2 and particulates out than normal and maybe affecting fuel consumption" and "your engine is running in a manner that will cause an imminent and expensive failure if let unattended'."

I suppose the problem with more granularity for general users (aside from the "confuse and anger" problem mentioned by Pogo_Fuzzybutt) is that said users would just ignore problems that the indicator says are less serious than others. I guess that maybe a "car imminently inoperable without repair" and "car needs repair" might both be serious enough that people wouldn't ignore the latter — though they might, after becoming aware that the former is always important and the latter isn't.
posted by Ivan Fyodorovich at 1:32 PM on March 21, 2012


And quite honestly, any system is prone to errors. In this case, I'd rather have it over diagnose than under diagnose. The more complicated your warning system is, the more likely it is to develop its own issues and quirks. Simple tools can be powerful tools.


...come to think of it, I wonder if the bulb in my CEL is dead.
posted by Stagger Lee at 1:51 PM on March 21, 2012


I suppose the problem with more granularity for general users (aside from the "confuse and anger" problem mentioned by Pogo_Fuzzybutt) is that said users would just ignore problems that the indicator says are less serious than others.

Yep. The more information you give people that have zero knowledge, the more chance of them making a decision based on what they think they know. To some extent, it's a case that only the clueless and the fully informed should be allowed the information - clueless gets the yellow light, informed gets the codes and the diagnosis.

If you start telling people what the issue is and that's all they have, the chances of them making the right decision (rather than finding a way to justify ignoring it) is low, I think.

...come to think of it, I wonder if the bulb in my CEL is dead.

Your CEL will illuminate, along with all the other warning lights, when you first turn the ignition on - easy to check. They all go out if everything is ok after a few seconds.
posted by Brockles at 1:53 PM on March 21, 2012 [1 favorite]


CEL lights are required to illuminate during the start up period for just this reason. See also ABS warning lights.
posted by Mitheral at 1:54 PM on March 21, 2012


It's the same when you call Apple Support, and they ask if you have zapped the PRAM or reseated the RAM or battery. It almost never is the cause of the problem, but it's an easy enough fix for anyone to do, that it makes sense to try it just to see.

This is a very good point. I was at a Pep Boys to get some tires installed, and another woman in the waiting room got socked with a $110 "diagnostic fee" because her gas-cap wasn't on properly.

So! If the Check Engine Light comes on -

1) Is it blinking? Stop. It usually means something bad has happened and will get much worse if you keep driving.
2) Check the gas cap. Take it off, make sure it's not cracked, and then put it back on, tight.
3) Take it to an autoparts store with a good reputation, like NAPA, and ask them to check the code for you. They often will do this for free. If not, rent the code reader. Match the code against the repair manual for your car, or look it up online. Contact your dealer to see if there's a recall that will correct what's wrong, and then contact your mechanic to discuss if the issue is serious or not, and get a preliminary estimate.
4) Note the driving conditions when it shows up, if it only comes on sometimes - time of day, the weather (rainy or drizzling, humid or clear), the temperature outside, whether you were in stop-and-go traffic or on the highway, going up or down a big hill, etc. The code still be stored in the ECU, so get the trouble codes read as in step 3. Contact your mechanic for further advice on what might be going on.
posted by Slap*Happy at 2:11 PM on March 21, 2012 [2 favorites]



Your CEL will illuminate, along with all the other warning lights, when you first turn the ignition on - easy to check. They all go out if everything is ok after a few seconds.
posted by Brockles at 1:53 PM on March 21 [+] [!]


Yeah absolutely, I just don't think I've ever looked, and I'm running a vehicle that's over twenty years old and has been cannibalized and rebuilt at least once, so I should really know better. ;) Thanks though. Wise words.
posted by Stagger Lee at 3:09 PM on March 21, 2012


Users of complex systems do best with simple warnings. The professionals know where to look for more information. If you give a user information that a professional would use, you will only confuse and anger them - for example "Illegal Operation Error".

Our societies understanding of how this does work, and how it should work, is deeply broken.

In particular..
It's the same when you call Apple Support, and they ask if you have zapped the PRAM or reseated the RAM or battery. It almost never is the cause of the problem, but it's an easy enough fix for anyone to do, that it makes sense to try it just to see.
This type of advice is routinely used to discourage service calls. If you make it hard to get things fixed--for lots of different values of hard--you get people improvising solutions or just ignoring some problems because fixing them doesn't seem worth the effort. Sometimes this leads to legitimate results, like when a major service disruption gets fixed, sometimes it leads to trashing products that are actually 100% fine with the tiniest bit of insight.

You also get companies manipulating the marketplace. My cable internet customers have to submit a two page report to open a trouble ticket. This is because the big company, Rogers (think Comcast but in Canada), doesn't want the small company my customers are buying from, Teksavvy, in business. Making simple things like opening a trouble ticket hard causes the customers to think the small company is incompetent. Worse than that, if the big company sees any minor inconsistency, like wrong firmware version on modem, they will blame that as the cause of problems regardless of actual relevancy to the problems being experienced.

Answers like "you have to have money to live" are really disgusting to me. Sure, we can have a society like that. We can have a society were water is a product like Coke-Cola, and not a right like air. We don't have to go that way though, we shouldn't go that way.

Some of the solutions are relatively easy.. You don't have to make a choice between granular information and general information. You can create documentation that takes you gently from the most basic to the most advanced. You can open up standards so that people can understand problems. You can have places like Ask MetaFilter were people can go and get help digging deep into the technical details. Other solutions are much harder.. I personally have big issues with professionalization, but professionals are nonetheless required for society and effective for the individual in the right circumstances.
posted by Chuckles at 3:13 PM on March 21, 2012 [1 favorite]


wow i just read this whole thing at work
posted by Avenger50 at 3:41 PM on March 21, 2012 [1 favorite]


I am like the official devil's advocate for this thread because zapping my PRAM fixed my laptop problem also.
posted by jessamyn (staff) at 4:21 PM on March 21, 2012 [1 favorite]


I don't see that as parallel, so much, though.

I see "My car won't start - it cranks over and over but just won't fire"

And the PRAM equivalent response being "Have you checked you have fuel in your tank?". Obvious, first principles that anyone can check before you delve any deeper or spend any money, kind of action.

Whereas the CEL kind of responses are (for the same kind of relevance and randomness that I see and often ignoring details that they obviously don't understand preclude their answer):

"When my car didn't start it was because I put diesel in and it was a petrol. You should check that"

"My car didn't start because my battery was flat - have you checked the battery?"

"My car didn't start because someone had stolen my engine - have you looked to see if you still have an engine in there?"

"When it happened to me it was because it wasn't my car and my key didn't fit and I'd sleptwalked into my neighbours garage, OH HOW WE FUCKING LAUGHED. Are you in your own driveway?"

"My car didn't start because I'd forgotten to fill it with oil and it turns out I'd GASPLODED the engine just before and oil was dripping out of it. Did you check the oil?"

In the laptop example its like someone saying "my laptop stopped working because I had pirated software and it had a virus. Run Windows update on your Mac".
posted by Brockles at 4:50 PM on March 21, 2012 [1 favorite]


The gas-cap is something it takes three seconds to check, and can save you a hundred bucks in diagnostic fees, and is something that happens all the time. Not telling them to check the gas cap before going through the hassle of finding out the trouble code is negligent.
posted by Slap*Happy at 5:23 PM on March 21, 2012


True. And in a thread that was "my CEL light came on for no reason/blinks on for a while" I'd suggest it myself. Just as much as I'd suggest "Maybe just check the fuel level" if it didn't start.

But in a thread that says "My CEL is on and the mechanic found a cooling system and a catalytic converter fault code when he read the codes" it ain't the bloody fuel cap. THAT is what drives me insane, and it happens a lot.
posted by Brockles at 5:26 PM on March 21, 2012 [1 favorite]


Brockles writes "'My car didn't start because someone had stolen my engine - have you looked to see if you still have an engine in there?'"

I actually had the answer to my "Why the SMEG isn't my frackin' truck starting" be "Someone stole my starter :0". I got to admit the guy was ballsy as the truck was parked on a fairly busy, well lit, mixed use residential/commercial street though it only takes about 2 minutes to pop the starter out of a 300/6.

I've also had some twit steal a battery out of my truck (different place and the truck was in my driveway) but that was more funny rather than the severe annoyance the starter loss was. It was funny because the battery was completely hooped as I'd burnt it up winching and just had it in the truck to stop the cables from shorting. I theorized the thief choose my old winch battery rather than the new starter battery sitting next to it because by chance the winch battery was side post and the starter battery top post. I laughed my ass off picturing the guy walking the alley's looking for a top post he could steal; lugging it back to his non starting car and then finding out the battery didn't work. Well worth the $2 a dead battery was worth at that time.
posted by Mitheral at 5:43 PM on March 21, 2012


Anecdotal:
Around here, car battery thieves always strike twice. The first time they make you go buy a new battery, they just recycle the old one for ~$5-10. The second time, they get a brand new battery. Happens often.
posted by TomMelee at 5:48 PM on March 21, 2012


When I was in College, one of the girls in my hall had the clutch slave cylinder stolen from her car. She came up to me and said "I can't drive my car - the pedal goes to the floor and stays there"

I trudged out, confirmed the symptoms and opened the bonnet saying "It kind of feels like nothing is connected to..... oh. Where the fuck is your clutch slave cylinder, it should be right there". She didn't find it as funny as I did, but it was weird considering it was a $20 part.
posted by Brockles at 5:53 PM on March 21, 2012 [2 favorites]


When my dad was a young, juvenile delinquent drag-racer (both informally and officially) he and a friend actually stole the entire transmission out from under a parked car in the middle of the night a couple of times. It was one of the stories that my dad's friends and brothers liked to tell about him that he actually kind of hated and was embarrassed by.

But how fun would it be to come out to your car in the driveway in the morning to find that it lacked a transmission?
posted by Ivan Fyodorovich at 6:22 PM on March 21, 2012


It'd cut way down on clutch wear, that's for sure.
posted by cortex (staff) at 6:25 PM on March 21, 2012 [2 favorites]


Well, I've wasted another perfectly good hour reading car talk.

Don't drive like my brother!
posted by MattMangels at 6:30 PM on March 21, 2012 [8 favorites]


> Knowing that a CEL is on is not even close to being able to guess at a cause of the problem.

Q. My problem is, my Check Engine light is on.

A. Wow, I had that exact same problem! But being mechanically inclined I just whacked mine with a ball peen hammer until it went out. Solved! PS, long term fix too! Over a year now and it hasn't come on once.
posted by jfuller at 6:45 PM on March 21, 2012


In fairness, gouging both your eyes out with a spoon* would have approximately the same result.

*Because it's dull, you fool, it'll hurt more

/Rickman
posted by Brockles at 7:01 PM on March 21, 2012 [1 favorite]


Someone threw eggs on my car last Halloween, but I never washed them off. Should I eat it?
posted by two lights above the sea at 7:55 PM on March 21, 2012 [2 favorites]


The headrests are easier to digest than the body panels, silly.
posted by Burhanistan at 8:17 PM on March 21, 2012


two lights above the sea, are you related to 'two or three cars parked under the stars'?
posted by MattMangels at 8:30 PM on March 21, 2012


> The ONLY way that you had any idea whether that fault was going to cause your car to explode into a blazing fireball or carry on for the next 20,000 miles perfectly fine is because you had someone check it.

What? No, come on. As mentioned above, a blinking CEL might mean something big like a coil-over-plug failing causing ignition missing in a cylinder and raw gas flowing into the first catalytic converter which will destroy it in short order (1998 VW Passat 4cyl).

However, a steadily illuminated EPA-mandated Malfunction Indicator Lamp (1996 & later cars) just means something in the emissions system is off (including evaporative emissions, thus the gas gap not being tight). If the owner's manual says its OK to drive the car 100 miles with a steady lamp, it's probably OK.
posted by morganw at 10:54 PM on March 21, 2012 [1 favorite]


Someone threw eggs on my car last Halloween, but I never washed them off. Should I eat it?

Eating a car usually causes severe gastric distress, and the things are loaded with carcinogens, so no, you should not eat it.
posted by Kirth Gerson at 4:28 AM on March 22, 2012


What? No, come on.

I was talking from the Lay person's perspective. They see 'your engine has a problem' and understandably can flop between expecting the worst and ignoring it.
posted by Brockles at 5:35 AM on March 22, 2012


My CEL came on this morning. I am so conflicted.
posted by smackfu at 6:23 AM on March 22, 2012


Thanks for the links to the Bluetooth diagnostic thingy & the Torque Pro app. I sent them to mr. epersonae and he was pretty psyched.
posted by epersonae at 7:44 AM on March 22, 2012


I got mine today and it is extremely fun to watch all the gauges go wheeeeeee!

I will not even mention what it told me my CEL meant, lest I risk making Brockles feel obligated to verify whether or not my interpretation of it is sound.

posted by SpiffyRob at 12:14 PM on March 22, 2012


My useless anecdote: I once was met a woman who had worked for one of the big car companies, when first computers were installed. They needed a way to indicate that something was wrong whether it be something that the diagnostics system had found something or the computer itself was misbehaving.

So they added a light in the dashboard, but didn't know what to call it. They decided that name didn't matter as marketing was going to change it anyways. Well, marketing didn't and thus Check Engine Light was born.
posted by zeikka at 1:08 PM on March 22, 2012


Wait, wait, wait. So you're saying there's a COMPUTER in my AUTOMOBILE? Where do I put the floppy disk? What happens if it runs out of memories? Can I install new software from my CD Player?
posted by TomMelee at 1:24 PM on March 22, 2012 [2 favorites]


Can I install new software from my CD Player?

On some cars yes.
posted by Mitheral at 2:16 PM on March 22, 2012


my useless anecdote: I am driving a rental car this week. When I went to the rental place they said "pick anything in the Compact area" and I chose a Fiat 500. It's a fun little car. However it has two Drive settings unlike any automatic car I'd ever seen before. One of them has an option to shift it "manually" with paddle shifters. Which, I hadn't expected. I usually drive a standard shift car so I felt like I could drive anything. I was wrong. I drove it off the lot and immediately rev it up to 8000 rpm and am wondering if it's broken or I am. Figure it's me and immediately pull over to figure out how to drive the damned thing. This is, actually, super difficult because all Fiat wants to show you is advertisements for how cute the thing is. The car has no manual. I eventually found some user forums explaining the paddle shifting which I still can't quite figure out but I can at least get the car into 6th [!] and cruise down the highway til I get to where I am going.

Long story short(er) one of the library school students at the place I was speaking was a car dealer during the daytime and actually figured out that the car has two Drive settings, the one I was using [where you shift, counterintuitively] and the other one, right next to it where the car does the shifting. However you can knock one into the other by bending down to pick up pork rinds from the floor.

Upshot: experts are useful and thinking that you are an expert is sometimes problematic.
posted by jessamyn (staff) at 2:24 PM on March 22, 2012 [1 favorite]


My second car was a Fiat. Spider, 124, black, rag. Mom said Fiat was an acronym for Fix It Again Tony. Funny because that's my name, but also the name of the CEO of Fiat at the time.

The car had miles of cables. Everything worked by cable. I replaced the transmission myself, without a lift, by putting the car on blocks, and placing the replacement transmission on my chest while on a creeper, and sliding myself under the drive shaft, and thrusting my chest up so that the shaft pierced the center of the new tranny. It's no wonder I have issues.

I loved that car, like no other thing I have ever loved before. Primarily because it was a poorly designed piece of shit that taught me how to fix things. I miss my 124. I miss that level of challenge.
posted by Toekneesan at 5:58 PM on March 22, 2012


However you can knock one into the other by bending down to pick up pork rinds from the floor.

What's the code for dropped pork rinds?
posted by Kirth Gerson at 6:29 AM on March 23, 2012


The car has no manual.

This is possibly the single fucking stupidest thing that rental cars do (among many candidates, admittedly). I've been in a similar situation where I wanted to know how to do something (Can't remember what, but assume it was ENORMOUSLY technical just to appease me) and there is never a manual in a rental car. I've rented hundreds and it is always the same. I assume it is so that it has a manual when they send it back off lease, but it is really stupid to rent out brand new cars - which means most of your customers won't be familiar with them - with no way to know how to work them.

Wankers.
posted by Brockles at 8:33 AM on March 23, 2012


Another random story: My mother, about 30+ years ago when she purchased her first car that had an alarm with it did not quite get the concept. She drove the car for a couple of years and then the "Check Engine Light" went on. She first noticed it when the car was in park before she drove it she says. She sees the light and promptly unhooked her hood latch and literally went to check the engine to see if it was still there thinking it was an alarm alert telling her it had been stolen or tampered with. My brothers and I still ask her if she has looked for her engine lately.
posted by JohnnyGunn at 9:41 AM on March 23, 2012 [1 favorite]


It's the same when you call Apple Support, and they ask if you have zapped the PRAM or reseated the RAM or battery. It almost never is the cause of the problem, but it's an easy enough fix for anyone to do, that it makes sense to try it just to see.

This type of advice is routinely used to discourage service calls. If you make it hard to get things fixed--for lots of different values of hard--you get people improvising solutions or just ignoring some problems because fixing them doesn't seem worth the effort. Sometimes this leads to legitimate results, like when a major service disruption gets fixed, sometimes it leads to trashing products that are actually 100% fine with the tiniest bit of insight.


Those things fix something like 80% of problems. I see it ALL THE TIME. The advice to do the "easy stuff" isn't to get people off the phone, it is because it is standard, correct troubleshooting procedure. You start by gathering the information that you can, and then you start applying potential fixes, in order of a combination of what's most likely and what is easiest/cheapest.

It is also to get the machine into a known state.

(I mean, just the day before yesterday, I had a machine whose fan had gone bad. I installed the new fan and powered up the machine. Lights and fans, but no POST. Pull the power, try again. Reseat all the plugs and RAM. Nothing. Reset the CMOS with the little jumper. Nothing. Pull the clock battery OUT, put it back in and the thing fires back to life. That doesn't mean that pulling the battery is going to be the solution for every problem like that. It just means that it was in this case. And when you are standing there with no other parts, it makes sense to try everything. Connectors get oxidation on them and sometimes go funny. CMOS (PRAM) sometimes gets corrupted.)

The whole point of this is Meta is that in order to diagnose something, you need to gather facts. In a car, all the light tells you is that there is SOMETHING out of specs. It doesn't tell you what. And that's what Brockles is complaining about- it's like saying "Dear AskMetafilter: the flag on my mailbox is up! How much is my cable bill?"
posted by gjc at 9:15 AM on March 25, 2012


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