Misfiring and Oil on Spark Plugs

[c0r3y.af]

Hey guys,

Recently did an oil change with my brother about two weeks ago. I was driving my car this weekend and it began misfiring with the CEL blinking. I immidiently brought it home and scanned it and received a 302 code which is misfire in cylinder 2. Pulled all four coils and spark plugs and noticed that the two middle plugs were covered in a decent amount of oil. Checked the oil level and it was a tad high. Looks like we may have overfilled it by about 1/4 of a quart but we did not notice at the time. I drained a little oil to get it back to the correct level, then replaced the spark plugs and cleaned all four coils with electrical contact cleaner and put them back in. The motor is still running very choppy after letting it go for 2-3 mins and I'm getting the same code. Any ideas? I'm hoping it's simply just a bad ignition coil but if not, maybe the valve cover gasket? Looking for any advice you guys can give. Thanks!

Edit: Forgot to mention the motor. This is an AEB 1.8t.

[l985xxx]

Two of my cars had that happen - once in my beater it was because my PCV stuff was clogged and falling apart, pushing oil past the rings. The other was two damaged valve seals letting oil pass into the chamber. Any smoke out the exhaust?

[Duds]

Most likely valve cover gasket.

[c0r3y.af]

Two of my cars had that happen - once in my beater it was because my PCV stuff was clogged and falling apart, pushing oil past the rings. The other was two damaged valve seals letting oil pass into the chamber. Any smoke out the exhaust?

Can't say that I've noticed any smoke in the exhaust which seems odd but I guess that's a good thing haha. Never thought of PCV but I gotta admit I've never had to replace this before. What should I be looking for? Also saw someone else mention the ICM but I don't really see how that would be related.

Most likely valve cover gasket.

A lot of the stuff I'm reading about seems to point to this but I don't really see any oil anywhere else. Just went and ordered the gasket kit just in case since it's cheap enough.

[l985xxx]

If you look into the spark plug recesses in the valve cover, look where the gasket is between the valve cover and head. A lot of times it will leak there, down into the recess and through the spark plug threads. All the PCV stuff is located under the intake manifold. There's diagrams on here - check the hoses/valves. As far as valve seals, I pulled my intake and exhaust manifold to see if there was excess oil on the valves - it was obvious that there were two exhaust valves with a lot of oil on them, but I was blowing smoke at cold start. Only other ways to get oil on specific plugs is bad rings, head gasket (not likely) or if it's actually just sooty fuel and not oil on the plugs, which might be a leaky injector or something.

[c0r3y.af]

If you look into the spark plug recesses in the valve cover, look where the gasket is between the valve cover and head. A lot of times it will leak there, down into the recess and through the spark plug threads. All the PCV stuff is located under the intake manifold. There's diagrams on here - check the hoses/valves. As far as valve seals, I pulled my intake and exhaust manifold to see if there was excess oil on the valves - it was obvious that there were two exhaust valves with a lot of oil on them, but I was blowing smoke at cold start. Only other ways to get oil on specific plugs is bad rings, head gasket (not likely) or if it's actually just sooty fuel and not oil on the plugs, which might be a leaky injector or something.

Great info, thanks a lot! I just purchased the gasket from ECS since that's the cheapest solution so I guess I'll start there. I will keep you guys posted. Now hopefull they'll ship my stuff sometime this week...

[Sidewayzracer]

Def replace the valve cover gasket, had the same happen to me twice once to far from home and ended up exploding the spack plug in half and melted the bottom of the coil pack

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[c0r3y.af]

Hey guys. So the car sat for a few days and I finally got a chance to change the gasket today. Everything actually went very smoothly and the new gasket is now on. It seems to have fixed the oil issue on the plugs as they're now coming out dry. My misfiring issue is still there though. Replaced the coil pack, moved them around and did some testing and I think I narrowed it down to the wire. Looks like it goes into the harness so I don't think it's a simple replacement, correct? Any ideas?

[poopie]

you need a new ICM (ignitions control module). very common issue

[Seerlah]

As mentioned above, it is more than likely the ICM. But you would want to pinpoint the which cylinder(s) is misfiring and go from there.

You basically just swap ignition coils, spark plugs, and injectors (in that order of testing units) to see if the misfires change to a different cylinder. For example, if the misfire is in cylinder 2, you switch the ignition coil to cylinder 3 and the misfire moves to cylinder 3, then that particular ignition coil is your issue. If the misfire stays in that cylinder, then do the same thing with the spark plug of that cylinder and see if the misfire moves to a different cylinder (one you moved that spark plug to). If it does, then your spark plug is the issue. Very rarely is it the fuel injector, but it is always a possibility. You would want to swap this to be 100% sure as to rule out all components dealing with combustion. But when it comes to the AEB engine, 9/10 it is your ICM. Other variables that can cause misfires are vacuum/boost leaks, clogged fuel filter, and a faulty MAF. Basically you need to figure out which unit is causing your issue (I listed the reasons why), and get that replaced.

And once again, I agree it is the ICM simply because it is very common on the AEB. But if the ICM does not fix your issue, look into the other variables I listed. But try swapping ignition coil, spark plugs, and fuel injectors first. This is a free test. You would need to be able to read your ECU though to be able to know which cylinder(s) is actually misfiring.

[c0r3y.af]

As mentioned above, it is more than likely the ICM. But you would want to pinpoint the which cylinder(s) is misfiring and go from there.

You basically just swap ignition coils, spark plugs, and injectors (in that order of testing units) to see if the misfires change to a different cylinder. For example, if the misfire is in cylinder 2, you switch the ignition coil to cylinder 3 and the misfire moves to cylinder 3, then that particular ignition coil is your issue. If the misfire stays in that cylinder, then do the same thing with the spark plug of that cylinder and see if the misfire moves to a different cylinder (one you moved that spark plug to). If it does, then your spark plug is the issue. Very rarely is it the fuel injector, but it is always a possibility. You would want to swap this to be 100% sure as to rule out all components dealing with combustion. But when it comes to the AEB engine, 9/10 it is your ICM. Other variables that can cause misfires are vacuum/boost leaks, clogged fuel filter, and a faulty MAF. Basically you need to figure out which unit is causing your issue (I listed the reasons why), and get that replaced.

And once again, I agree it is the ICM simply because it is very common on the AEB. But if the ICM does not fix your issue, look into the other variables I listed. But try swapping ignition coil, spark plugs, and fuel injectors first. This is a free test. You would need to be able to read your ECU though to be able to know which cylinder(s) is actually misfiring.

Thanks for the reply. I've tried switching those three around. Clearing the CEL each time and starting it up again gives me a 302 code so the misfire is staying on cylinder 2 which is why I thought it could be the wire. Never knew about the ICM so I'll look into it. Thanks.

[AudibahnA4]

While people are on this subject I found out that my car has a bad N75 valve. If that valve is bad can it cause the car to mis-fire really bad

[poopie]

Most likely not

[jackedrabbit]

A bad n75 will cause you to lose boost. Dosent really have affect on ignition.

What plugs are you using?

Are you chipped?

Ignition control module is most likely the problem as stated before.

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[c0r3y.af]

A bad n75 will cause you to lose boost. Dosent really have affect on ignition.

What plugs are you using?

Are you chipped?

Ignition control module is most likely the problem as stated before.

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Don't think I have any sort of boost problem. Plugs were replaced about a week ago and are OEM replacement Bosch since they were a little cheaper. The car is not chipped, although I would like to chip it in the future. I just ordered the ICM and I think you guys might be right about this one so I'll be installing it on Friday and will let you all know whether or not it works.

[jackedrabbit]

Regardless of what dealers recommend, standard copper plugs run so much better in these cars. It may be a good idea to switch. I run standard copper plugs in my car and I'm big Turbo. Most of the other guys do too. If not all. I get mine for $5 for 4 and I usually do them with my oil change every 5k

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[w4xm4n]

you need a new ICM (ignitions control module). very common issue

Just had the same issue and purchased a new ICM from ECStuning.com . It fixed the issue instantly.

After checking plugs, coil packs, injectors... ect.. This is what I would do

http://www.ecstuning.com/Audi-B5_A4-...ule/ES2526295/

[AudibahnA4]

Can a bad MAF sensor cause misfire

[c0r3y.af]

If your spark plug is black or oily than that means the engine is running too rich and is not properly combusting fuel. This problem can be caused by too much oil in the fuel and oil mixture.

Actually it was from the valve cover gasket which has now been replaced. No more oil

Just had the same issue and purchased a new ICM from ECStuning.com . It fixed the issue instantly.

After checking plugs, coil packs, injectors... ect.. This is what I would do

http://www.ecstuning.com/Audi-B5_A4-...ule/ES2526295/

Ordered that exact part on Monday, finally shipped today and I'll have it friday. Can't wait

Can a bad MAF sensor cause misfire

I would imagine that, if anything, it would cause random misfires. I've already narrowed this down to an electrical issue.

[AudibahnA4]

I would imagine that, if anything, it would cause random misfires. I've already narrowed this down to an electrical issue.

Yea I was just asking because I am having misfires with mine to

[c0r3y.af]

Yea I was just asking because I am having misfires with mine to

Aaah gotchya. Good luck, should be an easy fix. It seems to be pretty common from what I can see

[AudibahnA4]

Yea that was not the problem on mine. It actually turned out to be the MAF sensor

[c0r3y.af]

Just realized I never posted my results lol. To anyone who suggested the ICM - Thumbs up to you. I replaced the ICM a week ago and the car is running mint again