wimpy

iTrader: (2)

Guys need advise please.

I have a 1994 WRX with the following mods.
440's
walbro 255
FMIC
K+N induction
VF34
and its all being run by a Unichip Q+
It has been running fine up until end of last year but on the standard TMIC. I fitted the front mount and had it remapped and it was running fine at 0.9 bar boost at 311bhp with 341ft lb. Took it for a map tweak in January ready for the track season and we found a fuelling issue. Ay 4800rpm we get a little hic cup and the lamba starts to rise and the fuel starts to lean off. We have tried everything on the map ie adding more fuel taking away but at the same point each time this happens. We have set it to a safe map for now and spent a few hours checking things.

First we pulled out the new walbro to check it over and found a pin hole in the short bit of hose so replaced it. Done a power run, no change. Changed fuel filter and even changed the maf. Still doing the same. All boost hoses are fine. So all that I can think of is fuel pressure regulator may be shagged failing that it might be the Unichip.

So my question is could it be dirty injectors that only play up under full load or is there anything I may have missed. It would be good to get a fresh view as I am running blind in thick clouds so might be missing some thing simple.

Cheers
Iain

mickywrx

iTrader: (29)

Misread the hiccup as a misfire.

Have you checked the vac pipe from the fuel reg?

wimpy

iTrader: (2)

Yea checked all pipe work. The fuelling is spot on right up to the 4800rpm.