bsewall

Big thanks to Dave (turbo510) for the help!

Background:
Recently put in a used engine & turbo w/ 59k miles to replace mine which died at 230k miles. When mine died, I pulled the coilpacks and plugs only to notice they were both covered in oil. Also, I had to put on my stock exhaust to pass smog, even though the car is chipped. I don't think the mechanic who put in the engine did a good job as there were several unplugged sensors and hoses, as well as a coolant leak from the heater core piping flange.

Now that the engine is in, the car is misfiring under load. We hooked it up to a VAG and the codes were random misfire and misfire on cyl 3. We swapped out the cyl 3 coil pack and ran the car again, but still got a cyl 3 misfire.

Thinking it is maybe the ICM, we swapped that out as well, cleared the codes and ran the car again. This time we got a cyl 2 misfire.

At that point we decided to hold off and do some more research to see other possibilities.

What do you guys think it could be?

The coilpacks, injectors and cat are original (230k miles). The MAF and ICM were replaced about 4 years ago (60-70k miles maybe?).

rs4tech

how old are the plugs, try swapping them. typically if the icm fails it fails on cyl 2, out of the dozens of them i have replaced they all failed on cyl 2. if that doesnt fix it try compression/leakdown test of cyl 3. I know it might sound bad but maybe you got a bad used engine...

bsewall

Hi and thanks for the help.

The plugs are/were brand new. When I picked up the car from the mechanic replacing the engine, he said the plugs were bad, so I put in NGK 6962 Copper plugs. I suppose it wouldn't hurt swapping the plugs again.

We swapped out the ICM with a working one from a Passat, which didn't fix the problem. So we're pretty sure it's not the ICM.

I know the mechanic did a leakdown test before installing the engine and reported it was ok. He didn't want to install it if there were problems with the engine itself. When the engine wasn't running right when I picked up the car, he said it still has to be "tuned", but I don't know how he can do that without modifying the ECU programming, right?

Since I originally made the post, the misfiring seems to have gotten worse. It's far more sensitive to misfire under load and even has started misfiring when idling.

rs4tech

if swapping the plugs, coils, and icm didnt fix it. the only thing left to swap would be the injector...try swapping it with another cylinder and see if the misfire moves with it.

bsewall

The injectors are original, so that's very possible. I've never swapped the injectors before. Is it a difficult procedure? I really don't like the AW Wiki - it's so hard to find things compared to the old FAQ thread. :-/

EDIT: Found a link on the injectors here: http://www.a4mods.com/index.php?page...injectors.html

rs4tech

they are not hard, just unplug all 4 of them and remove the 2 bolts that hold the fuel rail on, then just pull the fuel rail with injectors out of the intake manifold...just make sure that you have 8 new injector seals as you might as well replace all the seals while you have them out. also make sure that you lube the injector seals real well before re intalling them so that they do not roll and cause a large vacuum or fuel leak

bsewall

Thanks for the tip!