fuel pressure problems

[ngtwlf2]

'85 omni glht with fairly new walbro 255 and accufab fpr and inline pressure gauge. at idle the car is only showing 35psi on the gauge, pull the vaccume line off and it shows 36...if i adjust the fpr the pressure only goes down...it goes down if i raise the pressure all the way...and i still can lower the pressure. i can hear the walbro turn on. do i have a problem with the pump or is the fpr bad?

[Stevien1]

While it's running, wrap the return hose with a rag and pinch it shut with some pliers. The fuel pressure should shoot up to around 80psi (or whatever the relief pressure is in your pump). If the pressure doesn't shoot up, you have a leak inside the tank (or on the ground- but you'd notice that right away, I hope!!!!)

If the pressure DOES shoot up, then you have a bad FPR. Swap in the stock unit and see what happens.

-Chuck James

[ngtwlf2]

thank you sir, ill give it a shot in the morning:thumb:

[tryingbe]

Did you use a fuel injection hose that is rated for IN-TANK use? If not, the rubber on the exterior of hose will dissolve in gas and give you low pressure.

[ngtwlf2]

no leakes anywhere...i pinched the hose on the return just with my fingers and the pressure shot up to 50+ psi...so im guessing its the regulator. the hose that was used was for intanke use.

[ngtwlf2]

did the rebuild on the regulator...didnt solve the problem so i guess ill be checking the intank stuff. odd question...could this be related to a vaccume leak? i pull the vaccum line off and the pressure isnt rising anymore.