fuel problem..PLZ HELP!!

[boss1984]

went to the dyno with my truck..i have a 400lph pump,60lb injectors and stock rails...everytime at 4500rpms it starts to run lean and drop fuel pressure...so im getting a new regulator in a couple days and a fuel pressure gauge so i can see if it drops after that..any ideas would be very appreciated

we've already upgraded the wiring:shrug:

 

[Fade 2 Black]

Your single pump can't keep up would be my guess. We all run twin 255 lph pumps and they hold up to over 700 rwhp. What is your base fuel pressure set at?

 

[boss1984]

Your single pump can't keep up would be my guess. We all run twin 255 lph pumps and they hold up to over 700 rwhp. What is your base fuel pressure set at?

idles at about 40 psi since i dont have a 2 step adjuster..mike at madenterprise had this pump on his truck with i believe 650-700ish and never had a problem..heres the thing, when we started the tuning we started with less timing and it made less power than it did before and its still running lean..it always runs lean at 4500rpms and up..no matter what it happens at 4500:shrug:

 

[mbsvt]

lean

Hmmm just a thought but look at maf voltage and load at that rpm, make sure your not pegging the meter.anything over 4.98 is not good. and fuel presure should be over 50psi under boost,But im sure u ck for that.
MB

 

[Fade 2 Black]

Who is tuning it and what is their take on the situation? They should have some data for you to view and explanation of what the engine is doing.

Is your fuel filter clean? If your FP is falling off there are only a few things it could be. Weak pump, partially clogged filter, regulator or that the tune is being done in a way to adjust the fuel table instead of the Maf curve. If the injector isn't modulating any longer (pulsing) and staying wide open then your FP will fall. Stock rails and 60's will support at or over 700 rwhp with proper supply.

 

[boss1984]

Thanks for the info guys. The fuel filter is brand new an the maf isn't near being pegged. So after I get a new regulator and my fp Gauge I'm gonna see
if it solves the problem. If not idk, maybe te
he pump is faulty. Keep options comming guys. I appreciate all the advice! Oh it's getting tuned at a very reputable shop near me!