My stage 3 B5 S4 will occasionally go into what I assume is "limp mode".

The car restricts boost to aprox 12lbs and fuels accordingly. A quick key off than on again and it goes back to usual.

Sound like an N75?
If so is there a better N75? like say an RS4 version?

AFAIK mine is still original.

Its been a while since Ive been on here.... Spring is on its way and the S4 will be on the road again soon.

Cheers.

 

Anyone?

K04-S4.... ever had this problem?

 

That's odd, perhaps a boost leak? You really need to run a vag scan to be able to really narrow it down. I just got a RACE N75 valve from ECS tuning, but i dont know if i'm going to use it. Its supposed to be faster in calling for boost. Again Scan it see why ur getting in limp mode. I had similar symtoms and it was a boost leak.

 

Thanks. Ill scan it and see.

 

Did you get the problem sorted out?

Sounds like a sticking bypass valve or boost leak as mentioned.

Curious to know the outcome (hope you had a good summer with your car).

 

Checked all kinds of things....... Gaps, boost leakes etc.

Got Vag. Scanned it. Egt sensor failing to ground.
EGT's coded out now and car runs great.

Thanks guys.