onecarTT

Hi all. While I have been reading the forum for sometime, this is my first post and let me also apologize for its length. I am having a common problem that I have seen posted here but I am in need of some insight and advice.

A few months ago I decided to do the 80K service myself including the spark plugs. All seem to go well until the next morning when I started the motor and had a very rough idle and miss-fires to the point where I had to shut the motor down. When I restarted the motor a few hours later all was well.

As part of the 80K service I had a qualified mechanic replace the timing belt and valve cover gasket. Before the service I had been experiencing occasional hesitation in the mornings. Since the service I am experiencing severe hesitation and some misfiring. The symptoms occur every time I accelerate hard and starts just after the turbo boost comes up.

Before I go any further, here is the set up:
2001 225R Quatro with an AMU motor
MTM modified ECU (installed in 2001)
Forge DV006
Forge Exhaust
OEM “E Type” coils
NGK PRF6Q plugs gapped @ .32

So much for the symptoms. So far I have done the following trouble shooting:

Checked gap on all plugs. All plugs were gapped correctly.
Checked wiring harness, found/tapped multiple cracks in wiring insulation.
Test drive showed no improvement, still had severe hesitation and some exhaust “popping”.

Replaced MTM ECU with stock ECU. Great improvement. Really had to work hard to get the hesitation to occur but was able to recreate some, and the “popping” was still present in the exhaust.

Installed MTM ECU and replaced fuel filter. Still had severe hesitation and some backfiring

Here is what I have concluded from reading other posts on this site and searching online and is where I need input:

Possible causes:
Cracks in the wiring harness is causing arching/grounds.
1 or more coil packs are bad

Anything else I should be considering?

I have decided that I have to repair the wiring harness no matter what else may be wrong. I have read the post in FAQ https://forums.audiworld.com/tt/msgs/1419073.phtml) but I am not comfortable doing that much surgery. Has anyone here used the Karlyn Ignition Coil Connector Kit to do a harness repair?
http://www.partsgeek.com/catalog/200...ector_kit.html

BTW I do have the Ross-Tech software that I use to check codes and reset basic setting. Other than that I am not knowledgeable enough to use the tool safely.

Again, my apologies for the length of this post…..SM

Statenheimer

I was getting a severe misfire at high rev high boost instances just a few weeks ago.

2001 AMU REVO remap.

Car would drive fine under "normal" circumstances, but upon heavy application of throttle, and again, high rev, high boost situations, I would get hesitation, misfire, and blinking check engine light, under the most severe instances.

I diagnosed it as fault coil pack[s]. I am very much one for the school of thought that they are all just as old and if one is bad, the others cannot be too far off...

I purchased 4 new coil packs at the best price I could find along with 4 new gaskets and 4 double platinum plugs.

Upon replacing I also found the cracked insulation on the wiring harness [to much dismay]...

However: Upon replacing the coil packs etc., the car feels like brand new, and pulls harder than it has in I-don't-know how long.

Take this story for what you will, but it sounds to me like you are having the same type issues, and the reason the stock ECU made the problem so much better is that you were not reaching the boost levels that you are with the MTM tune, therefore not making it as difficult for the plug to spark.

onecarTT

StaTT, Thanks for your input. I think I will follow suit and replace all 4 coil packs.
Two questions:
Did use replace with the OEM or with after market?
What gaskets did you replace? I have bolt on coil packs and there were no gaskest between the head and the coil.

I am going to repair the harness with the Karlyn Connector Kit . Happy to post the pics if you are interested in how it turns out. SM

Statenheimer

These are the coilpacks that I used. OEM VW/Audi.

I have the same bolt down style as you, and did not have existing gaskets between, but they are supposed to have THESE.

I am very interested in the Karlyn Connector Kit, do you have a link? And please do post your results

Statenheimer

Edit: Saw your links above... duh.

Actually think I might go for the entire wiring harness replace outlayed in that one thread...

Would be a great piece of mind, and a fun weekend project [yes, I'm like that]

Python021

as a mechanic i advise you to have someone connect to the car and tell you which cylinders are misfiring, replacing all coils (btw those were really cheap in cost, not sure the value) could hide another smaller issue

onecarTT

Python021, thanks for the reply. I pulled the codes a few days ago and found the codes for multiple random misfires (P0300)as well as specific codes for cylinders 3 and 4(P030 and P0304. I figured with 2 CPs having problems doing all 4 would be the best approach. I do plan on repairing the harness before replacing the CPs just to see if the wiring is the cause but I will probably change the CPs anyway.

Statenheimer

I know that the cost was very low, that is why I posted for others. They are OEM parts and come in the OEM VW/Audi boxes.
Therefore, I put the value quite high...