not enough fuel... question

[DaveR_GT]

Can anyone help?

I have my car on dyno and can't get enough fuel. We keep adding fuel up above 5000 but it isn't responding. Fuel pressure is holding steady, making me think it isn't running out of pump. I think the injectors should be big enough. Anyone have an idea where the restriction is? The car drives fine but I have to stay off the throttle because by 6000 rpm the AF is about 13.8.

Combo:
stock bottom end
TFS TW heads, stage one & port matched to GT40 intake
36# injectors
284HR Comp Cam
70mm TB
75 mm air meter
255 lph pump
stock fuel lines, filter (new), rails
Powerdyne XB1, showing 9# boost
power pipe
no FMU

I was contemplating adding an inline pump but if fuel pressure isn't dropping I am thinking the pump isn't the problem. Then i thought about putting the FMU back on to see if that did anything, but again, pressure doesnt' seem to be the problem.

Any ideas?

Thanks
Dave

 

[HO93LX302]

Well to start, try changing your fuel filter.. Its possible it has a small clog in it because of the crap in the filter..

 

[DaveR_GT]

did that already, no change.

 

[HISSIN50]

time to tune - as i understand it, the puter will 'retune' your increased FP after some time, making it a moot point to an extent.
good luck Dave.

 

[DaveR_GT]

Sorry if I wasn't clear...

We are trying to tune it. They keep giving it more fuel, more fuel and it isn't responding. They told me that if I got it fixed, like by changing the filter or adding an inline pump and fixed the restriction I'd know it.

The computer is trying to add so much fuel up top that it'll run way rich, smoke out the neighborhood, if I do fix the restriction!

Problem is, the filter is okay, and fuel pressure doesn't drop off. Before i waste money on an inline pump I wonder if there could be another problem. Like, at what point do the small stock fuel lines become a problem?

Thanks