hi i have a very anoying hesitation on my frst 1990 seems fine if i drive steady but if i am in say 3rd gear at about 20 or 30 mph then accarate hard the car comes on full boost ok but the power delivery is very staggered it has no probs pulling right throught the rev range but the power seems to come in in stages
also sometimes i have been driving along off boost in 4th or 5th an i get a sort sharp jolt from the engine like a power cut ive changed the plugs,leads,crank sensor,checked timing,checked co set at 4% so not to lean at idle
iam running a 195 chip with 701s and 14psi boost
any ideas guys or am i looking at a rolling road

 

Are the plugs gapped correctly? If the gaps are too big the boost might be blowing the spark out.

 

good point will have to check ,should the gap be smaller than spec as iam running more that standard boost

 

I think they need to be about 25 thou. Can't remember exactly as I just hand my car over to my bro for stuff like that.

 

It sounds like it may be leaning out at the revs get higher, it may be ok on idle but its a different case once its moving. What you describe sounds like it could be a weak mixture, had the same on mine many moons ago, had to replace the fuel pressure regulator. See if your plugs are white.

 

Have you changed the fuel filter recently ?
tabetha

 

hi i have changed the filter and set the fuel perssure to 3 bar. will the 701s run on the standard management with out the chip so i can see if its the chip as superchips have reflashed mine to a stage 2 not long ago but i would have expected them to test that after tho

 

thanks guys found the problem it was the fuel pressure regulator only holding 2 bar on full boost
i have fitted a new one and the pressure went up to 3.5 idle 4 bar when reved and drives like a different car pulls very well
my only other question is what should i set the pressure at???