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i just got my fuel pressure guage installed and noticed that when the car goes into boost the fuel pressure will rise to about 70 or 80 then it bounces around like crazy from 40 to 80 and its all over the place need suggestions on what could be cause this also do you think it would be ok to go with no fmu and a adjustable fuel pressure regulator mods are full exhaust, trick flow intake, 70mm mass air , 30# injectors walbro 255 hp pump novi 1k will be putting the f150 pulley back on tuesday.?
Are you running the stock fuel pump now?
I think if you are that is your problem, it just cant meet the demand.
You can dump the FMU with your mods, the 255 & the 30's will be enough.
ok i am gonna go ahead and get rid of the fmu then. but i would still like to know what could be cause my fuel pressure to bounce all around it is not a stock pump it is a high pressure 255.
What is the FMU calibrated for. I may be interested in buying it. let me know if you want to get rid of it.
its calibrated for 30s i think i still have the original 19 calibration also i will let you know i have to see how it runs first without it then i will post back.
send me an email at tram1062@bellsouth.net if you want to sell the FMU that is calibrated for the 30s. I have 24lb injectors and i am not running an FMU right now and i am running a little lean but if i use the FMU i have (the original 19 calibration) i run so rich its crazy.
ok but what about my fuel pressure probloem anyone have any ideas what is causeing this ?
try disconnecting the FMU first like they said. possibly it is hooked up wrong or is defective
something else i have come to find when i shut the car off fuel pressure is still at like 40 or so then i will come back later and it will be lower is this a sign of a leak and how would i find a leak if there was one? Or is it supposed to do this i dont think it is
i belive it is suppose to do that b/c mine does the same