Negative Boost Deviation (again)

Simon L

Audi TTS

Sep 24, 2004

1,253

0

Glasgow

• Dec 26, 2005

• #1

I seem to keep getting this fault, especially when the air is very cold.

Same story as usual, 4th gear, WOT, Around 5k.

Hitting around 12psi, then limp mode.

The car has been running really well recently however. Not had limp at all for weeks.

Any suggestions? I really want to get this fixed.

Previously i've tried swapping the N75J back to the standard N75C, still hit limp. Also tried swapping the Forge DV back to the standard Bosch DV, still hit limp.

 

Simon L

Audi TTS

Sep 24, 2004

1,253

0

Glasgow

• Dec 26, 2005

• #2

Also the MAF is still reading ~150g/s

 

DPJ

...........

Dec 13, 2004

7,996

2

NN Yorks / Salento

www.seatcupra.net

• Dec 26, 2005

• #3

Simon L said:

Also the MAF is still reading ~150g/s

Click to expand...

MAF g/s is consistent with your bhp, Simon. What N75 did Star map the car with?
Can you post requested v actual?

 

Simon L

Audi TTS

Sep 24, 2004

1,253

0

Glasgow

• Dec 26, 2005

• #4

The C i believe.

But i have spent time trying both C and J, and the fault happens with both.

But not so often with the J. Plus with the J the car drives better.

 

Simon L

Audi TTS

Sep 24, 2004

1,253

0

Glasgow

• Dec 26, 2005

• #5

Will get a log later on tonight.

 

DPJ

...........

Dec 13, 2004

7,996

2

NN Yorks / Salento

www.seatcupra.net

• Dec 26, 2005

• #6

Other than that, look at overfuelling and the timing being pulled back?

 

cordobabrendy

FOOORRREEE!

Aug 24, 2001

7,642

1

belfast

• Dec 26, 2005

• #7

for what its worth with revo on my motor ive tried most of the n75s just out of curiosity, none of them caused limp mode. perhaps something else is adding to this?

 

Simon L

Audi TTS

Sep 24, 2004

1,253

0

Glasgow

• Dec 26, 2005

• #8

I misread the error, it was actualy a Positive boost deviation.

But i did some logging anyway...

3rd and 4th gear run, 2'C temp outside...

The boost looks fine to me, the N75 isnt maxed out and even the inlet temps are low, its just the CF that bothers me. Anything above 3 is bad right?

 

Last edited: Dec 26, 2005

cordobabrendy

FOOORRREEE!

Aug 24, 2001

7,642

1

belfast

• Dec 26, 2005

• #9

crap fuel and warm intake (not really that hot) could be causing it.

 

Simon L

Audi TTS

Sep 24, 2004

1,253

0

Glasgow

• Dec 26, 2005

• #10

I wasnt long in from work, and it was a 30 mins enthusiastic drive home. So the inlet probably was still hot.

Full to the brim with BP Ultimate.

 

cordobabrendy

FOOORRREEE!

Aug 24, 2001

7,642

1

belfast

• Dec 26, 2005

• #11

the high cfs are showing quite bad detonation in 4th gear....i wouldnt even guess why but it shouldnt be as consistantly high in the first place.

 

Simon L

Audi TTS

Sep 24, 2004

1,253

0

Glasgow

• Dec 26, 2005

• #12

Perhaps the CF is related to the delivered boost exceeding the requested boost?