Fuel problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Racer497, Aug 25, 2003.

  1. Racer497

    Racer497 Newbie

    May 24, 2003
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    Hey I need some help with this one. I just got my 89 k5 with a 350 unstuck, went to start it and it would just crank. It's got spark, so I figured the fuel pump went out. did some trouble shooting and pulled the plug that goes to to fuel pump off. The plug I pulled was the one right infront of the rear axel. Put direct battery power to it and it would work. So I don't know what is up. we found the rely and there is a red wire coming outta the bundle that has a plug on it but nothing attaced to it. I don't remember if soemthing goes there or not. right now I am just chaceing wires and u guys are my last hope. I have a chiltons that has the wireing guide in it but some of the wire colors aren't the same. There isn't a fuel pump fuse I seen. I need HELP!!! quick too cause my buddy wants it outta his garage. Please e-mail me with help please I don't check here too often BSchutter@juno.com Thanks
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Feb 17, 2000
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    If you can fire the pump with external power does it run?
    When you first turn the key to run the fuel pump should cycle for 5 seconds. Check that. If you hear the pump then the problems is somewhere else.
    The fuel pump relay has a test plug on it that doesn't plug to anything else.
    THe ECM get's it's trigger sensor from the same place as the coil does. So if you have spart then it should get a trigger signal.
    Start with stupid stuff. Unplug and check all the conectors and make sure they are not full of crud and rust.

    Any codes in the ECM?
  3. dyeager535

    dyeager535 1 ton status Premium Member

    Dec 13, 2000
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    Roy WA
    If the relay is bad, it takes oil pressure for the pump to fire up. If the relay is bad, and the pressure switch is disconnected or bad, then you'd get no fuel either.

    Pretty unlikely for both to fail, which is why it is set up that way, but worth checking out.

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