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Richard

Richard 3/9/2014

1998 Chevrolet C1500 Cheyenne 8 Cyl 5.70L

Engine

I have changed fuel pump but no preasure what causes fuel pump not to pump changed fuse

new fuel pump and fuse still wont pump

3 Answers


Jimm

Jimm 3/9/2014

The fuel pump should run as soon as the ignition key switch is turned 'on'. The fuel pump energizes to pressureize the fuel system in order to feed fuel to the engine. Check the fuel pressure at the fuel rail - at the engine. There is a shrader valve / port to attach a fuel gauge and read system pressure from the fuel pump; usually around 20-30 PSI with the key 'on'.

If the fuel pump pressure is minimal or not up to specification - suspect the following; faulty fuel pump wiring / connection, faulty / clogged fuel filter, faulty fuel system regulator.

The parts are readily available from these many on-line sources, www.partsgeek.com, www.rockauto.com, www.discountautoparts.com, www.autopartswarehouse.com, www.jcwhitney.com - to list only a few possibilities.
In fact, they (RockAuto) list the fuel filter from around $1.80, and the pressure regulator from around $32.80 for your vehicle

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Jimm

Richard 3/9/2014

Thanks so much ! Richard

HouseCallAuto

HouseCallAuto 3/9/2014

Richard, can you get access to the electrical plug that is at the fuel pump and check for battery voltage on the gray wire and ground at the heavy black wire in the same connector? You can use a 12 volt test light. I am assuming that you are saying that the fuel pump is not turning on because if it were you would hear it humm for two seconds and stop each time the key is turned to "on". I can give you add'l diagnostic info after you get this far.

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Affordable Auto Service

Hi Richard, Why did you initially replace the pump. I'm assuming it quit working and the pump was identified as being defective. When you replaced the pump did you get a new pigtail to wire up with the pump? If you did and didn't install it that can be the problem as aftermarket part companies will change the wire locations. If you did verify that it was wired correctly. One crossed wire can cause the problem

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Affordable Auto Service

Richard 3/19/2014

Thanks Richard

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