constant misfire in 3rd cyl, even with new coilpack/plug

[bernB5]

car's been running great for the last two weeks. yesterday, i was letting it idle in the driveway for about 10 min while i went inside to get something and by the time i got back to the car, it was misfiring with a flashing CEL..

if the CEL is flashing, most likely it's the coilpack. So, after I spent the day trying to get my hood open (the cable disconnected from the latch) I finally got in there and replaced the coilpack.. turn on the car and still misfiring.. Take the plugs out, cleaned them all and even swapped a different one in the 3rd cyl to make sure... still misfiring.
I ran the vag at idle and in less than 30 seconds I already had 85 misfires in cyl 3.
At one point, I turned off my motor and it sounded like something was clapping around inside the engine.. it was kind of like a really loud dripping noise, if that makes any sense. After a few times of shutting it off and hearing this weird noise maybe twice, I unplugged the injectors and did a compression test in all cylinders..
1 = 165
2 = 180
3 = 180
4 = 175

For a motor with 130k on it and stock rings, I'd say I'm in good shape.. But, I just don't know where this problem is coming from. Hopefully nothing is wrong with the motor (rod bearings?)--which were replaced during the rebuild at 124k. The noise has not been repeated bu the misfiring is still there. Any ideas?

[Ewok_Fetus]

Swap injectors around and see if it follows... Also test your ICM...

[MikeWasHere05]

ICM.

[bernB5]

ignition control module? hmm... It's been fine, don't see why it'd randomly crap out while idling but I'll check it..

[audinutt]

ignition control module? hmm... It's been fine, don't see why it'd randomly crap out while idling but I'll check it..

The ICM's do and WILL randomly die on you. trust me

-richard

[Ewok_Fetus]

LOL! Just like timing belts don't crap out after 60k miles... Right?

[AudiRacerS4]

a bad ICM will cause a cyl 2 misfire almost all the time

[Mad_Audi]

my car was missing on 3rd cylinder. ICM was the culprit

[bernB5]

what about cyl 3?

also, how can you test the ICM?

[k0mpresd]

only way to test is to replace it/swap with a known good one.

you replaced the entire coilpack? sometimes the booty on aeb coils can fail and cause misfires. but not usually all of a sudden like that.

[bernB5]

didn't "replace" as in buy a new one.. I had another coil laying around because the rubber gasket came off. I know it works though, so kept it as a backup.

I'll order a new ICM tomorrow and hope for the best, unless I can find someone local to swap in and see if it works.
Thanks guys, I'll keep you updated..

[audinutt]

only way to test is to replace it/swap with a known good one.

This is NOT correct.

Look here for the test procedure.
http://forums.audiworld.com/a4/msgs/1594531.phtml

-richard

[burner799]

cylinder 3 on the failed ICM for me as well. I have a beru and I don't know how much it has done to protect the new one but, I used silver heat dissipating gel on the heat sink part of it. Read somewhere on here that it may help keep it working longer

[317ssayzarc]

try the icm bernie

[k0mpresd]

This is NOT correct.

Look here for the test procedure.
http://forums.audiworld.com/a4/msgs/1594531.phtml

-richard

im sorry. what i meant to say was you can spend an hour doing a bunch of garbage to see if your icm is bad. or you can take 30 seconds and swap it with a good one.

[Ewok_Fetus]

It's better wasting your own time than to waste someone elses....

[k0mpresd]

but i have more important things to do. like stare at my computer screen. :p

[bernB5]

Ok.. That test looks cool, but I'm way too lazy.. I ordered a new ICM unit last night from Autohaus, $108.. It'll be here tuesday, which is fine because I need spacers and can't drive my car without them anyway, so no big rush.

I've basically done ever test on the car to narrow it down to the ICM, so I'm confident.
Thanks for all your help. I <3 this forum.

On another note, on 20psi I'm still not pulling ANY timing, so once this is sorted and I put my new inlet in, you'll see some numbers.. Looking to go to E-town next Friday night if anyone is interested (cough---JAKE---cough cough)

[317ssayzarc]

Ok.. That test looks cool, but I'm way too lazy.. I ordered a new ICM unit last night from Autohaus, $108.. It'll be here tuesday, which is fine because I need spacers and can't drive my car without them anyway, so no big rush.

I've basically done ever test on the car to narrow it down to the ICM, so I'm confident.
Thanks for all your help. I <3 this forum.

On another note, on 20psi I'm still not pulling ANY timing, so once this is sorted and I put my new inlet in, you'll see some numbers.. Looking to go to E-town next Friday night if anyone is interested (cough---JAKE---cough cough)

once i get the tune right possibly... but it costs me a shit load of time and money to trailer the car down to etown...

[bernB5]

i still can't believe you're having such tuning troubles.. Did you change your fuel filter yet?
Trailers are for pussies, drive that isht! :)

[317ssayzarc]

havent changed the filter yet, but i have the wideband going in tommorrow and will get an idea of where im at

[bernB5]

havent changed the filter yet, but i have the wideband going in tommorrow and will get an idea of where im at

good, i love having my wideband, but at the same time, driving at night with that thing is one of the most annoying/distracting things, aside from my retarded loud turbo.