$teady$upreme

https://forums.audiworld.com/a4/msgs/2140768.phtml

So after swapping the coilpacks and plugs, i still got the same fault codes. So that means i didn't have problem with coils and plugs.

Then a week ago, we moved on the check the ignition control unit using this link: https://forums.audiworld.com/a4/msgs/1594531.phtml
and found gold(not quite)... i had some numbers on cylinder 1,3,4 but no numbers on 2.

So today, i have a chance to replace my original ICU with my friends(it sure works). Before i replaced it, i tried starting the car using the original ICU, but it didn't start(it used to start but bad idle, and blinking CEL). So I replaced it and move on to clear the codes. And this time it starts and it has a solid CEL, then i scan it one more time with VAG to see if the previous codes are cleared. But no, the fault codes stayed the same, 16884 and 16886...

after all these testings, what can i do next??
please bare with me, i haven't driven the car for two weeks already, i really want to get it fix soon.

thx in advance everyone~

RKA

You might have left the cylinders pooled with fuel when you attempted to start it again with the bad ICU. That might have tripped the fault codes initially. The fact that the CEL isn't blinking anymore is a good thing. I would just run the engine for a bit to clean out any unburned fuel from the cylinders, remove and replace the spark plugs in case you fouled one of more of them, clear the codes, and try one more time. I'll bet the car will run fine with no CEL.

$teady$upreme

but having a solid CEL is a good thing eh?
so now i should just start it and let it runs for a bit? or just go ahead and change the plugs?

but somehow my tech was suggesting to check with wires that are connected to the ECU and ICU, any ideas?

RKA

From your post it kinda seemed like it. You just seemed concerned with the code that popped up again. Changing the plugs is easy to do, so it's worth a shot.

If that doesn't work, then I would swap fuel injectors between a "good" cylinder and a "bad" cylinder, and see what that does for the codes.

Checking the wiring is a good suggestion, but I honestly don't remember the last time I saw anybody post indicating that their wiring harness had fried and led to misfiring. Not to mention, chasing electrical gremlins is a pain in the a$$. Try all the easy stuff first.

Yippers®

codes. I suggested he swap plugs in that thread too

RKA

Maybe I need a BFH to drive the point home?

Yippers®

But keep that hammer handy just in case .. lol

crashman

DONT KNOW IF WILL HELP BUT,
https://forums.audiworld.com/a4/msgs/2132821.phtmlSAME THING HAPPENED TO ME BUT NUMBER ONE. SWITCHED IT ALL AROUND AND NOTHING. STILL NUMBER ONE. OUT OF DESPERATION PULLED CAMS AND LOW AND BEHOLD BROKEN EXHAUST VALVE SPRING. DONT WANT TO SCARE BUT IF ALL OTHER THINGS ARE CHECKED.

$teady$upreme

but i don't think i be able to trace it.
i did what i can do already, maybe is time to tow it to a shop.

$teady$upreme

and drove around, my car still had a solid CEL on. But after more driving(20km), all of a sudden the CEL is gone. cheers!

thx very much RKA.