No one knows the cause of CEL, now what?

[Hieu]

I’ve had a few threads on here:
http://www.ericthecarguy.com/kunena/8-Service-and-Repair-Questions-Answered-Here/56243-2000-integra-ls-auto-random-misfire-con-t

I’ve taken my integra to two different Acura dealerships and despite spending hours on the car, no one could figure out why it is misfiring or could replicate the issue. I’ve done ALOT of diagnostics and replaced many, many parts with OEM acura parts to try to fix the issue but no help at all, the problem shows right back up. One master technician and shop manager said, it may be a bad ECU but he would have to order a brand new one to test that theory, at my cost. I could go for a used one but the newest used one on the market would be 15 years old (probably in no better shape than mine) and with the immobilizer in the 2000 integras, it could get tricky, not DIY.

So what now? The car won’t pass inspection with that light on. I can’t get the emissions systems “ready” before the misfire code pops up. What happens in this case? The car runs perfect and gets great gas mileage. What typically happens in this case usually? (preferably a legal solution)

Topic

[college man]

By looking at the plugs from the previous thread they look like your lean.
Usually white ash is oil or fuel additives sticking to the plugs causing the
fouling. which is triggering the misfires. since they all look about the same.
Its either fuel or spark related.Have you checked your ignition timing?

[dan]

with College man on this one, what he says makes sense, white residue on the plugs usually mean you are burning oil or something in the fuel is sticking too the plugs and is not burning thoroughly, Considering you are having misfires as well on all cylinders i would make sure you have plenty of spark and that it is in time…

if your ignition system is not in correct time it won’t burn the AF Mixture properly, if it sparks too early it causes knock, if it sparks too late it causes misfires, spark should happen a few degrees before TDC is achieved during the compression stroke, what ever degree that is depends on the vehicles specs… and if you ignite the air fuel mixture too late you will have misfires because the air fuel mixture is not compressed optimally and the piston is not at the correct position as specified.

if your spark is also too weak it won’t be strong enough to ignite the air fuel mixture.

[Hieu]

I haven’t checked ignition timing, will definately do that as soon as I can, thanks for ya’lls posts.

[college man]

[quote=”hpracing007″ post=146008]I haven’t checked ignition timing, will definately do that as soon as I can, thanks for ya’lls posts.[/quote]

Keep us posted on your progress. 🙂

[Hieu]

Quick update, I haven’t ordered a timing light yet so that’s my bad (did watch ETCG’s video though, very helpful).

The light turned off all of the sudden. It’s not burned out because it will light up and turn off at start off.

The light very very rarely (1-2 times a year over the last few years) turns off on it’s own, then comes back in about 1-2 weeks. The car was parked in a parking garage and it had just rained a lot, so the streets were wet. But as I was driving, the CEL just turned off for no apparent reason, wasn’t accelerating, was driving like 20 mph. I think several of those rare times in the past, but not all, this happened after rain.

How does the CEL light work anyways? Do misfire codes get cleared out after a certain amount of time if the engine does not experience one again?

[EricTheCarGuy]

Even if the light isn’t on, there can be a code stored. Also, Honda ECU’s rarely every go bad without outside interference. That said, has anyone checked the mechanical integrity of the engine? That engine is famous for wearing out piston rings and also burning up exhaust valves if the valves aren’t adjusted properly. Anytime you have an issue like this you MUST verify the mechanical integrity of the engine before you start throwing parts and sensors at it. I cover that in depth here.

http://www.ericthecarguy.com/faq/solving-automotive-performance-issues

Good luck and please keep us posted. Also, please keep things in the same thread instead of starting a new one. That way when there’s a resolution we can follow it to it’s conclusion.

[Hieu]

Hi Eric.

At least 3 Acura technicians and myself have checked the mechanical integrity of the engine (well at least I hope they did 🙂
The first visit was at an Acura dealer in Austin. The last 2 visits were actually very comprehensive, I actually used to work at that dealer as a salesman and the shop foreman was the guy who did my timing belt at 90k, they really wanted to figure it out. I got the car looked at 190k miles and they drove the car for 20-30 miles and did their diagnostics and couldn’t find anything. Then I took it back to the Acura dealership at 195k for them to do a full timing belt/drive belt/water pump, coolant, and service. They had the car for 2 days and had no idea what is causing it.

I’ve adjusted the valves myself using your video. Compression test about 10-15k miles ago: 4, 3, 2, 1 (200 psi, 195 psi, 190 psi, 195 psi)
I’ve done vacuum leak test, power balance test, ect but will take a closer look at your link tonight.

Also will add other than a K&N drop-in air filter which was installed over 10 years and cleaned yearly, an generic radiator, and a puralator oil filter, the car is 100% OEM stock.

[Author]

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