Fuel pump goes out every two days

General Discussion
1

1994 Chevy z71 … We have replaced my sons fuel pump 4 different.times within 6 weeks and it just keeps going out. What could be the problem? Please help

2

Bad pumps? New or rebuilt pump?

Clogged line that’s causing too much back pressure.

Quality of pump you’re buying.

3

Delfye (not sure on spelling) and Bosch . We bought the full assembly all brand new. My son is 16 and had an amp hooked straight to the battery someone said that could be the problem but I don’t have much knowledge in this area

4

Delphi

Not knowing anything else about the amp’s installation, I’d say that could be your problem. Pumps don’t just fail 4 times

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5

Could be the amp, we had a radiator fan that was wired wrong when replaced that killed our fuel pump

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6

Infantile failures happen because:

  1. They are defective
  2. They are starved of fuel
  3. There is excess backpressure due to blockage in the outlet fuel supply lines
  4. They are starved of adequate power to run efficiently

#1 is unlikely due to how many have been gone through and the relative high quality of pumps being used.

#2 is possible if some mistake is being made in the installation. The act of pumping gas both lubricates and cools the pump.

#3 can be verified by doing a fuel pressure and volume test.

#4 is probably the highest probability. If the electrical supply integrity is compromised, then the pumps can be starved for power, run hotter and fail early. This could be the fuel pump relay, wiring and/or corroded harness side connectors. One way to diagnose this would be to measure the supply voltage directly on the pump connector while the pump is running.

If this external amplifier is overloading the electrical capacity of the car by design, it could be starving the pump as well.

This leads to the question- define “goes out”. Has anyone looked at the problem from a diagnostic perspective or just keep swapping out pumps? What exactly is wrong with the pumps? Is the pump failed but the motor still runs? Is the pump motor seized or did the windings burn up? How they failed and some simple diagnostics will lead you to the solution…

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7

There’s a misdiagnosis going on. It’s a power supply issue;or lack of power.

8

We are talking about an older car - any chance of rust/dirt/contamination in the tank?

9

Is this a failure to crank being blamed on a bad fuel pump?? A no crank problem is a battery, starter or alternator issue or… an amp that never turns off and drains the battery overnight.

10

If the symptom – whatever it is – is caused by a faulty fuel pump and a replacement pump quickly fails also

  • fuel line between pump and engine is restricted, clogged fuel filter for example, & this restriction quickly damages new pump. Measure fuel rail pressure and pump flow rate.
  • power supply to pump is faulty, high resistance connection, bad ground, broken wire, relay problem, wiring harness problem; i.e. the pump isn’t the problem, it just isn’t getting a good source of electrical power. Measure the power supply voltage at the pump.

What is the symptom? And what makes you believe the fuel pump is the cause?

11

Thanks for the reply. I don’t think it is the fuel pump but that something is causing the fuel pump to go out. We definitely will be checking the possibilities suggested. Thank u

12

What happens when the pump"goes out"? Does it crank without starting? If so, spray some starting fluid into the air cleaner. If it doesn’t start up and run briefly while cranking then, it is not a fuel issue.