the truck in my sig, no longer has the procharger kit on it. my question is what is the correct fuel pressure for this truck? the pressure i am seeing is, 43-48 at idle roughly 48-51 cruising, and a max of 50-55 at WOT. I was under the impression that these truck were supposed to operate at around 60 psi. it has the factory fuel pump in tank, and it has the added in line pump. truck runs fine, im just curious

back when i was procharged i had very weird fuel pressure too but i thought that was due to the FMU.

 

Should be about 58-60 psi with the pump running and engine off (no vacuum). The fuel pressure will decrease when the manifold sees vacuum. Your numbers do seem a little bit low to me though.

 

thats what i thought too. it only spikes to about 55 psi for a second when i first turn the key on then settles back down below 50 psi. what could be the issue?

 

If you're running a stock FPR it could be bad. How long does it take for the pressure to bleed off after you shut the truck off?

 

yup running the stock FPR, the truck only has 67,000 miles on it. it takes a while for it to bleed off completely, is there any way to test the FPR?

 

Pull the little hose going to the intake and if theres gas in there it's probably bad. Common issue.

 

think i found the problem. the FPR is working fine. no fuel in the vacuum port, and also raises pressure when vacuum is removed. i pulled the fuse for my in line pump today and let the factory pump do the work, well the fuel pressure dropped below 40 psi. so id say the factory pump is going bad. im thinking of changing my in line pump to a walboro and that should be enough to maintain the correct pressure right???

 

If the factory pump is going bad you need to replace it. You'll put too much strain on the inline trying to draw through a bad in-tank pump, and then your inline pumps will start failing too.