fuel pump problems

[Bill59]

I need some suggestions about a fuel problem I'm having. Most of the time when I turn the key, I can hear the fuel pump run for 1-2 seconds and the engine will start. Other times, the pump runs continuously and the engine won't start. I tried a fuel pressure tester on the fuel rail and found that it took awhile to build pressure, so I replaced the fuel filter, which didn't help. When releasing pressure with the tester, I sometimes get air, along with gas coming out of the line, which usually solves my problem. What would cause air to get into the system? Any suggestions? I'm tired of getting stranded!

 

[IMenriched]

I need some suggestions about a fuel problem I'm having. Most of the time when I turn the key, I can hear the fuel pump run for 1-2 seconds and the engine will start. Other times, the pump runs continuously and the engine won't start. I tried a fuel pressure tester on the fuel rail and found that it took awhile to build pressure, so I replaced the fuel filter, which didn't help. When releasing pressure with the tester, I sometimes get air, along with gas coming out of the line, which usually solves my problem. What would cause air to get into the system? Any suggestions? I'm tired of getting stranded!

bill59
I feel your frustration and understand.

pressure readings are key....the pressure readings tell the story.

Key on engine off (KOEO) should produce some where in the area of 30-40psi

Key on engine running (KOER) should have similar readings

KOER crack the throttle and pressure should increase a bit, maybe 10psi....if the pressure drops with crack of the throttle, that is a sign the in-tank pump is weak or fuel restriction (fuel filter plugged )

shut engine off...if pressure drops shortly after...the high pressure pump has a bad check valve, the check valve is built into the pump.

higher pressures than 40-45psi, indicates return line restriction or FPR is bad

Lower pressure readings than the desired 30-40psi indicates bad high pressure pump or severely plugged fuel filter
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