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1992 Chevrolet S10 Blazer Question: no power to fuel pump relay

 

Question

ldmoiles, Corunna, MI, February 11, 2010, 09:25
 Rookie

My blazer stopped running. I replaced fuel pump, filter, and relay. The fuel pump didn't run when I turned the key on. I checked power at the relay and have .3 volts. I changed the pcm and I am still only getting .3 volts.

5 Answers
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  • Answer #1

    Bret Bodas from RepairPal Test Shop, February 11, 2010, 12:44
     Master

    Are you getting ignition spark to the plugs? Some vehicles need to see this ignition signal before it will energize the fuel pump.

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    ldmoiles, February 11, 2010, 12:53
     Rookie

    yes it is getting spark.

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    Bret Bodas, February 11, 2010, 13:00
     Master

    I don't have a wiring diagram, but is this a 4 wire relay? If so, does it have the 12 volt signal and a good ground? And is it the signal from the PCM that is .3 volts?

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    ldmoiles, February 11, 2010, 13:28
     Rookie

    yes it is a four wire relay. their is .3 volts coming from the pcm on the orange wire which should be 12volts of constant power feeding the relay. The pcm, engine, and fuel pump all have a good ground.

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    Bret Bodas, February 11, 2010, 13:39
     Master

    If you disconnect the relay and check the 4 terminals, you should have:
    1. A good ground connection
    2. A 12 volt signal with the key on
    3. A wire that has continuity between the connector and the fuel pump
    4. A wire between the connector and the PCM
    I wish I had a diagram to tell you which wire is which, but I think you have that figured out. Can you check all these and verify each wire is OK?
    Have you tried jumping power to the fuel pump and see if it runs?

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    ldmoiles, February 11, 2010, 14:07
     Rookie

    their is a good ground and continuity threw the wire to the fuel pump. there is no power on the other two wires. I did check the pump and it does run when it is powered up.

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    ldmoiles, February 11, 2010, 14:23
     Rookie

    Got it! I changed the ECMB fuse which at first appeared to be ok but after closer examination found it had blown.Blazer is running now. Thanks for the help!

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    Bret Bodas, February 11, 2010, 14:29
     Master

    Great! The good news is the fuel pump probably caused the fuse to blow, so that may have needed replacement anyway.
    Please do me a favor, I am curious, how much did you spend on all the parts you replaced, and did you consider taking this to a shop to have it repaired? And why would you not take this to a shop?
    Thanks!

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    Bret Bodas, February 16, 2010, 13:36
     Master

    So does this mean you're not going to answer my questions?

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    Bret Bodas, March 04, 2010, 14:49
     Master

    Come on, not even a little help with my question?

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  • Answer #2

    Visitor, May 23, 2010, 06:34

    I had problems with the wiring . I replaced the wire to the relay that provides power. I also ran a new wire to the fuel pump from the relay.

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  • Medium-star Best Answer
    Visitor, August 05, 2010, 13:41

    not applicable

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  • Answer #4

    Visitor, September 22, 2010, 08:51

    use a gm fule pump

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  • Answer #5

    Visitor, March 07, 2011, 09:28

    tie into the ground wire coming out of the wire harness coming out of tank and ground to the frame that fixed mine after several people were left scratching their heads

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    spoonman73, February 15, 2014, 14:51
     Rookie

    This is not an answer, but when I hooked the ground up to the frame, does it matter if there is rust and what not or should I have sanded it down to bare metal?

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