Negative Boost Deviation (again)

[Simon L]

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]

Also the MAF is still reading ~150g/s

 

[DPJ]

Also the MAF is still reading ~150g/s

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]

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]

Will get a log later on tonight.

 

[DPJ]

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

 

[cordobabrendy]

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]

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?

 

[cordobabrendy]

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

 

[Simon L]

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]

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]

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