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-   -   My check engine light is on (http://cellar.org/showthread.php?t=22430)

Shawnee123 04-21-2010 12:32 PM

omg

Again, bad joking on my part.

I'm gonna quit for the day (well, probably not.) :)

Cloud 04-21-2010 12:34 PM

Well, I can ask. I can ask for the parts that were replaced. I can read the description on the invoice. But otherwise, I pretty much have to take their word for it. Do you have a better idea?

Shawnee123 04-21-2010 12:37 PM

No I don't have a better idea.

Sigh.

Mostly, I get so sick of everyone waiting around like spiders for any slip-up they perceive from tw...no, not you. So, it followed that mechanic man said "yeah" and...

Nebber mind, again.

Cloud 04-21-2010 12:40 PM

spiders! spiders! get them OFF me!

(runs screaming into the night. . . . okay, the afternoon)

Flint 04-21-2010 12:48 PM

Put some electrical tape over the little lights on your dashboard.

Issue resolved 04/21/2010. Left vm for customer, no cb. Closing ticket.

Cloud 04-21-2010 01:00 PM

that would be nice, if 1) the engine wasn't acting up; and 2) I didn't have the inspection sticker problem

guy called and said that he's still getting the same code, and so he's ordered ANOTHER PCM to be installed next week. I guess we can only try, but I'm feeling very discouraged.

tw 04-21-2010 02:20 PM

Quote:

Originally Posted by Undertoad (Post 650608)
I am shocked SHOCKED that the mechanic performed the checks that tw repeatedly complained he must not have done.

He did what I posted and did not do what I suggested. Please read what was posted.

Problem is intermittent. If an intermittent IACV, then he did nothing to identify a sticky, temperature sensitive IACV. He did what a diagnostics chart says to identify a constant (hard) failure. Apply voltage. Hear it click. But this is not a hard failure. A valve failing as I have suggested will always pass that test and continue to fail intermittently.

What UT did not read. An IACV works by opening and closing quickly. So fast that only an oscilloscope can see that timing. Did you read the word ‘oscilloscope’? Now read what was posted and tell us the mechanic did what was suggested.

Computers rarely fail. And do not fail only when an engine is warming up. Valves that fail only during warm up do so intermittently. Which part more likely causes an intermittent?

My second point that UT did not read: Mechanic is now doing only what he understands - shotgunning. Just keep replacing parts until something works. He reloaded software. No change. Replaced the computer. No change. So he is replacing the computer again without any reason to believe it is bad. At what point does it become obvious that the computer probably is not a problem? He has resorted to the “I don’t have a clue” option. Shotgunning because he has no idea what else to do.

The best part to shotgun is the one most likely to cause this type of intermittent (heat related) failure. What was posted, and not what UT read. UT go find a paragraph that includes the word oscilloscope. Now read this time what was posted.

Well, he is replacing a second computer - for free. If that does nothing, he should then shotgun the part that was more likely defective - an IACV. I put an IACV at about 65% likely to solve the problem - which is why I so dislike shotgun solutions.

Cloud 04-21-2010 03:11 PM

which is why I so dislike car problems. blecch!

Undertoad 04-21-2010 03:24 PM

Very well, sir, we don't know what he meant by "check voltages". But I'd wager he did what the service manual told him to do.

tw 04-21-2010 09:19 PM

Quote:

Originally Posted by Undertoad (Post 650670)
Very well, sir, we don't know what he meant by "check voltages".

'Check voltages' is about disconnecting the valve from its connector. Then measuring voltage on that connector. It says power is provided to the valve. We already know that. The valve works most of the time. That measurement does nothing to find an intermittent - only identifies a constant failure.

Moving on to what is known - new information for Cloud. IACV fully opens when the car starts. That is why a car is started without pressing the accelerator. The IACV valve does that automatically. If the IAC valve does not open, then the car would not idle at a higher rev - ie 1200 RPM. Therefore that valve operated normally when the car first started.

As the car gets warm, the valve remains mostly closed. But if a warming valve gets stuck, then the car will run rough (too lean) until that unpowered valve eventually frees itself; and closes.

Of course a fully depressed accelerator would make that stuck valve ‘not apparent’. So yes, what is done to make ‘roughness’ no longer happen would be a critically important symptom.

Cloud 05-06-2010 01:21 PM

yep, it's still on. After a computer update; then a replacement; then a replacement for the replacement.

I have very few options. I can keep throwing money at it, (and NO, sorry, I'm not going to start messing around under the hood myself) and hope someone can fix it. Or I can just drive it until it dies, until I need my new inspection sticker (in August), or I feel ready to get a new car.

54,000 miles. bugger.

jinx 05-06-2010 02:14 PM

Quote:

54,000 miles. bugger.
Holy crap, I've got more on my jeep...

Cloud 05-06-2010 02:25 PM

yeah. Makes it harder to get a good used trade in.

lumberjim 05-06-2010 02:41 PM

take the bulb out, and trade it in

classicman 05-06-2010 02:59 PM

^^listen to Jim^^


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