Help, Boost problem advice

[GavS2]

Hello fellow S2 owners. I'm looking for some advice, i have an S2 aby engine and i'm suffering loss of boost intermitten. What is happening is, as the revs gets higher sometimes the boost disapears then comes back, sometimes theres no boost at all and sometimes its totally fine. When this does happen, sometimes i can smell fuel which i guess is un-burnt. I've checked all the boost hoses very carefully and there seems to be no holes or leaks there, so is it maybe a wastegate problem ? I don't know. I'm a panel beater by trade so bodywork is more my thing, not to hot on engines. If anyone has any ideas where to look next that would be great. Thanks guys, Gav

[WabTheKing]

Leaking injectors maybe? Have you checked for fuel leaks etc?

[andyg plym]

is it ok when you switch engine off then back on?

im thinking knock sensors

[GavS2]

I have looked to see if the injectors are leeking, it did'nt seem to have any evidence that they where, but i will have another closer look at that, it was something that crossed my mind, thanks.

I have not tried the knock sensor idea though. I'll try that, although i say its intermitten, its does seem to do it on every journey now and i think its got worst over a few months. Cheers

Good advice guys, keep it coming cheers Gav

[Big Lee M]

DO you have a boost gauge fitted? Does it feel like limp mode? I'm thinking faulty N75

[GavS2]

No i have no boost gauge, i guess that would help keep an eye on it. As for the N75 valve, what exactly is that ? i here it spoke about alot on the forum. Is it the valve type thing behind the drivers side headlamp thats connected to the wastegate and other boost hoses ? i'm guessing its not the dump valve, i did change that for a new bosch one six months ago, when i had a nasty misfire caused by the coilpack amplifier number 2 breaking down, diagnosed by MRC tuning. And can you believe your luck coilpack amplifier number one died on me two weeks ago, changed it misfire gone again. But now i have this new problem. So the N75 ???

[UrS4boy]

..., i did change that for a new bosch one six months ago, when i had a nasty misfire caused by the coilpack amplifier number 2 breaking down, diagnosed by MRC tuning. And can you believe your luck coilpack amplifier number one died on me two weeks ago, changed it misfire gone again. But now i have this new problem. So the N75 ???

If one POS (power output stage (aka amplifiier)) dies, I would expect the other to die very soon. Here is some POS info:

http://forums.quattroworld.com/s4s6/msgs/15284.phtml

On the N75 possibility, here is some info to read:

http://forums.quattroworld.com/s4s6/msgs/20987.phtml

Good luck.