3b boost problem please help!!!!

[BosnianS2]

hello people
I have 3B engine in my 93 audi 90 and car has been runing good until couple days ago.
What started to happen was that car is pulling great unti i reach about 4000 RPM and than cuts the boost off. I have installed boost gauge so that is how i can tell definately that boost is cutting off. i have tried running manual boost controller to see if maybe my WGFV is bad, then boost is not droping off but at same spot engine(about 4000 RPM) i can feel that it quits pulling again i think ECU drops timing or something, basicly goes in some sort of limp mode home. I pulled codes and and none are stored. Any ideas would be greatly appreciated.

[martinjs]

Check all your boost pipes you may have a leak, and all the small diameter pipes connected to the back of the inlet manifold. If any of these pipes are split it will cut out like you say.
Could be the intercooler o-ring also. Bin that and fit a 70-60mm reducer pipe.

[quattronutter]

possible air temp sensor on top of inlet manifold??caused me the same symptoms on my old ur quattro,or boost leak,best to do a pressure test...

[S2central.net]

And don't forget to reset the ECU, by pulling fuses for a minute. This clears the fault from ECU memory.

Paul

[Mihnea]

Check the position of the distributor, the distributor gear might be cracked or starting to crack.

If the distributor is not aligned properly on its marks when the engine is at TDC, the ECU will cut boost, exactly as you are experiencing, and without any fault codes.

I could bet money that this is your problem, BTDT.

HTH,

Mihnea

[BosnianS2]

Thanks a lot for all replies guys, soon as i get off the work today i will get on that. I will let you guys know if i find anything out.
I live here in USA and nobody in my state drives car similar to this so i am on my own when i get problem.
Thanks a lot guys.

[BosnianS2]

And also for Martinjs, i run custom fron mount intercooler, beacuse original s2 or rs2 parts for that matter are hard to come byhere at USA. But i will double check all my connections again, i did this several times but i will do it again. Thanks for the info.

[BosnianS2]

whats up guys
i have to thank all of you for help. I finaly fixed my car. It ended up being the intake temperature sensor. I pulled it off and plastic piece that surounds the small wire that measures temperature broke off. I have no idea how it happen, but i had another one that was installed in intercooler form audi 5000 that i had laying around. I checked numbers on them and they were the same. The car is strong again and runs very smooth. This made it even better because this weekend there was corvette get together in my town, becasue i live in city where they were built, so i had little fun. hehe
thanks for all help guys.

[newsh]

Glad you found your problem. That old air temp sensor eh? I've had that on a ur but never on the 3B, yet, missing at 4k though, is quite a common thing on 3Bs apparently, we had it off and on whilst remapping mine so I may just go ahead and get me a new sensor.

Strange that there's no fault code stored.