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2003 Pontiac Grand Prix Question: What could cause a fuel pump to come on when the key is turned, but no fuel?

 

Question

Jim Helterbrand, Hillsboro, OH, February 02, 2013, 18:33
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I am on my second Delphi fuel pump , both with the same results. Have checked the relay under the hood, and triple-checked the new fuel module plug; still no fuel comes out of the flow line from the pump.

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  • Answer #1

    February 02, 2013, 19:14
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     Master

    Did you replace the entire pump module or put a new pump in the old one? You say the pump is workng but no fuel right?
    If you replaced just the pump itself possible hose from pump is defective, wrong pump or running backwards, out of gas, filter on pump pick up clogged, external filter blocked, just some things that come to mind. How/where are you ckecking pressure?

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    goodguy, February 02, 2013, 21:17
     Master

    I agree with wetry you should check the fuel pressure

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    Jim Helterbrand, February 03, 2013, 07:42
     Rookie

    I replaced the entire fuel pump twice, each time with a new delphi pump. No pressure coming from the flow line at all. Was thinking about the junction box that the fuel module wires run to.

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    pushrod, February 03, 2013, 08:19
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     Master

    You stated pump would come on when key is turned on, is that right or not?? And where are you testing for fuel flow??

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    Jim Helterbrand, February 03, 2013, 10:52
     Rookie

    Pump comes on and can hear humming when key is turned on for about 5 seconds but no fuel comes out. to verify it, I took the flow line off of the top of the fuel pump and held my finger over the port from the pump. No pressure built up behind my finger.

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    pushrod, February 03, 2013, 11:03
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     Master

    IS THERE ENOUGH FUEL IN THE TANK? IF the pump is sitting in gas and it is running it has to pump gas as soon as it starts to run!! Unless the pump is defective. (not likely) That is all there is to it. The pump only runs a few seconds until key is cycled again or starter is engaged.
    Sorry but that's all i got!

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    Jim Helterbrand, February 03, 2013, 13:35
     Rookie

    Don't be sorry. I need any help that I can get. But yes, there is a little less than eight gallons in the tank.

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    pushrod, February 03, 2013, 13:52
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     Master

    Are you sure you are checking the pressure line and not the return? I think the pump is working and you have another problem.
    Is the ignition working, getting spark? May need to get some visual help on this one. Fuel pressure needs to be checked at the engine test port with a fuel pressure test gauge.
    Good luck!

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    Jim Helterbrand, February 04, 2013, 05:04
     Rookie

    I thought I might have gotten the lines switched as well; however, both ports are marked with a "F" for the flow line and an "R" for the return. In addition, they are different diameters so it would have been impossible to switch them.

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    faulconer79, December 26, 2013, 20:02
     Rookie

    I would check your fuel pump regulator its under the hood hidden well. U can bypass it to make sure it is problem its real simple there videos on YouTube just have to bend one prong on a relay.new regulator about 55 dollars at GM only place oriellys wont have clue and very simple to replace took me 10 min

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