I need some help bad, car is a 94 with 6# vortech, 36# injectors, 255 fuel pump brand new, LT headers, 6 speed. Ok here is my problem when i got my initial tune from pcmforless i tried it out and at 5500 it would pop like it was lean, well i check the fuel pressure and sure enough it was dropping. So i put in new walbro pump and fuel filter, pressure is still dropping under boost, so i unplug the fuel regulator because i thought that maybe boost was messing with it, still dropped. Also it was reading bad lean, but blowing black smoke out. So i done what we done with a friends car that was having the same problem i took some fuel out of the tune and sure enough my pressure came up and it got richer.

Now the original tune he sent me my injectors were at 86.5 duty cycle. Now the datalog looks much better but when i take one of the plugs out and look, it is white on the very tip with stuff flaking off of it, but the base around the electrode is black like it is very rich. Any suggestions? Take out more fuel? boost reference regulator? I wouldn't think that 36# injectors and a walbro 255 would not be enough fuel for the car. But what is everyone elses opinions or experiences?

 

Oh and by the way originally the tune i got had the WOT VS RPM table at 12.1 and now i have them at 6.8, anyone one with their own numbers please post.

 

I think 36s are borderline too small to go !FMU. Min I would get is 42# and a boost referenced regulator. Just my $.02. If you use a non-boost referenced regulator you got to program for going lean in boost and hope you have enough fuel cause your FP is going down in relation to manifold pressure as boost rises and the FP is static.

 

Anyone else have any opinions?

 

I agree with Kevin. The 36's are borderline. I have 42#'ers in my car with an s-trim. I am not running an FMU. I had the fuel curves programmed into my PCM.