on a 4L HO whats the fuel pressure on the rail supposed to be? mines 32-34 with the vacuum line connected to the regulator, and only goes up 1 or 2 psi when i disconnect the regulator. the book says it should go up 10 psi so i replaced the regulator but it didnt do much different. is my fuel pump weak?
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fuel pressure on the rail 91 HO
- Thread starter my77gmc
- Start date
Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
It might be a little weak, or you might need a fuel filter. Since the regulator sets the lower limit rather than the upper, a correct reading there indicates that it's all right.
Any symptoms, or just testing?
Any symptoms, or just testing?
yeah, a little rough idle, sounds like its missing, but i get no codes, might be nothing. im driving 3600 miles in a couple weeks n need everything to be "up to par" ive already changed the fuel filter, those readings were taken after changing the fuel filter and the pressure regulator.
Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
I wouldn't expect the rough idle to be a fuel pump issue, because if it can hold the correct pressure while idling, then it's delivering enough fuel. I'd start to worry if it can't keep up to 31 under running conditions.
