Muleski

I've S'd TFA's on this extensively. This one has me, and my indy tech {who'd a very good one...all Audi} stumped. I would appreciate any suggestions.

I had two coils that were progressively failing a couple of weeks ago, and made the decision to go with an O34 HO coil kit. After installing that, we had a ton of overboost. Replaced the WG Diaphragm, which we found had a tiny tear, and all seemed better. That was after either checking, or swapping to check, the MAF sensor, the ECU, the N75.

Now, the car runs excessively rich with any boost. If it's over 5 psi, the car starts to flood out and stumble. The car is held back. We checked for vacuum leaks under pressure. Appears fine. Pressurized it to 20 lbs, and it will maybe drop a pound over 5 minutes. My tech has also "smoked" it, and no apparent leaks. If we drive it for 5 minutes, and try to get it into boost, the plugs are black....as is the exhaust. It stumbles and the fuel smell is incredibly strong.

If we keep it out of boost, at the 5 psi, it will pull very smoothly either under load, or with no load to 6000 rpm. No problems.

The car's at my tech's right now, and he and I just spoke. I've only owned the car for about 18 months, and haven't had years of experience with the car. I've learned a tremendous amount from this forum and from searching. My tech knows Audi fuel systems inside and out, but he's stumped right now. His comment was that there has to be some small thing that he's overlooked on a UrS. As he says "there has to be something...some small hose that I'm overlooking"

The car is a 1995.5 S6. 82K miles. AI stage III+ chip, new this summer...4K miles ago. Stock WG spring. New Samco's this summer with Breeze CT clamps.

Any suggestions?

Thanks a lot. I appreciate any and all input. I'm normally able to search and pick up a lot, but not this time.

4Driver4

Check the Samco where it meets the crossover pipe - visually.

Muleski

Will do in the AM. Car's not with me now. Thnx.

ImQuattro®

They typically don't go bad on our cars but if you find fuel in the vacuum line or the vacuum line isn't there or has a hole/crack in it, the fpr will "think" the throttle is open or opening. This results in more fuel delivery all the time.

Also, a failing oxygen sensor or coolant temp sensor can cause a rich-run condition, as the ECU may see a lean mix and try to richen in up or thinks the engine is cold and do the same.

just some ideas...

Muleski

Sent you an email. Looking for a steel crossover pipe. Saw that you mentioned one a few days ago. Thanks.