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John, ASE Master Technician
Category: Chevy
Satisfied Customers: 614
Experience:  ASE Certified Master Technician, ASE Certified Service Consultant, 22 years professional experience
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1989 Chevy 1 Ton Fuel Pump Intermittenly Does not work, no,

Customer Question

1989 Chevy 1 Ton Fuel Pump Intermittenly Does not work
JA: Has your car been stalling?
Customer: no
JA: What is the model of your '89 Chevy?
Customer: c3500
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: i work in a shop and customer has replaced several things himself
JA: Anything else you think the mechanic should know?
Customer: only the left side fuel pump works customer states it has been that way since he bought it. it has a 350 with throttle body injection. sometimes the fuel pump will turn on when key is turned on and sometimes it will not
Submitted: 1 year ago.
Category: Chevy
Expert:  John replied 1 year ago.

Hello, my name is John.

Likely the fuel pump has a bad commutator on the pump motor and will intermittently not run (like a stater that fails the same way). Try banging on the fuel tank to see if jiggling it makes the pump come to life. Or, verify power to the pump from the relay (in the harness near the pump) at key on or jump the relay. If power and ground are okay at the pump then the pump is definately failing. If it is intermittent and won't quit for you then try lab scoping the pump and watch for the waveform to wander up and down indicating a worn pump bearing.

Please let me know if I can be of any further help.

Expert:  John replied 1 year ago.

Just following up to see what you found out. If you have found the information I have provided to be helpful, please provide a positive rating for my answer.

Thank you