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Discussion in 'The Garage' started by bear76, Aug 24, 2006.

  1. bear76

    bear76 1/2 ton status

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    Today I put in a new Fuel tank, straps, sender, pump, and all related parts. Feeling good about all this (4hrs) I added 5 gallons and puffed my chest out then turned the key. I herd the pump run for about 2 seconds and nothing after that. Truck never stared. I looked at the relay and it looked fine. Anyone have any ideas?

    BTW, it's a stock 91'

    Thanks.
     
  2. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    The pump will only run for a couple of seconds each time you switch on. Did you crank it for long? If you didn't have a problem before but have one now, you'll have to check everything you've done. Are you 'sure' you tightened the hoses to the pump securely? Haven't left any lines clamped?
     
  3. bear76

    bear76 1/2 ton status

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    The pump ran once and not again. All conections were triple checked before installing the sender/pump, and all fuel hoses are fine, I went back and checked again. The old pump went out and I figured I might as well replace everything while I had the tank out. But yes, it is same as before alot of cranking and no fuel or pump running.:dunno:
     
  4. chalet2506

    chalet2506 1/2 ton status Premium Member

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    Seems odd that your old fuel pump went out and now your new one runs for a bit and goes out. I'd get your multitester out, sounds like you've got an electrical issue.
     
  5. bear76

    bear76 1/2 ton status

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    I hate electrical. But I'll do it. Would I be able to check the pump conection on the frame rail with just the key turned to ING. or do I need someone to crank while checking? beyond that is the next place to check the relay on the fire wall? If anyone could give me directions on what to check first thru last I would appriciate it.:bow:
     
  6. k20

    k20 3/4 ton status

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    On the fuel pump relay, hook a wire from the little red pigtail wire (about 6" long) and hook it to the positive side of the battery. That will force the fuel pump to run. I believe it will also bypass the relay. If the pump works, then I would think that all of your connections and wiring from the relay to the pump are fine, and the problem lies either in the relay, or the wiring before the relay. With the pump shorted, try to start the truck, if it still wont fire, you have some other issue.
     
  7. bear76

    bear76 1/2 ton status

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    Should I leave the relay conected or pull apart?
     
  8. k20

    k20 3/4 ton status

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    yeh, leave it plugged together, I dont think the little pigtail works if its unplugged.
     
  9. bear76

    bear76 1/2 ton status

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    Well the good news is I just "jumped" the relay and the pump dose work:D . Bad news is the truck still won't start:mad: . What should be the next course of action?

    Thanks.
     
  10. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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    Your pump is only going to run long enough to pressurize the system.

    I believe you should be able to see fuel coming from the injectors. You could also get a test light so see if the injectors are firing. Test lights are only like $6.

    Did you replace the filter? Could it be in backwards?

    You know I hate so say this, but a couple of times I've done a big job on a vehicle and then had it not start. Ended up being nothing related to what I'd just done. Very frustrating.
     
  11. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Check your ecm B fuse. Any codes? As MtK5 says, can you see fuel from the injectors? It's should be a good healthy spray.
     
  12. k20

    k20 3/4 ton status

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    Could also be a temperature sender in the manifold if you arent getting fuel out the injectors. I had the sensor go bad, kept the injectors from firing. It was stuck on 210* when the truck was at 40*. Theres one sensor in the head, for the gauge, and one on the front of the intake manifold. The one in the manifold runs the computer.

    Also, like someone else said earlier, unplug one of the injectors, plug in a NOID light (I got one couple years ago, out of one of the little plastic bins at advance for like 99 cents), and see if the injectors are getting an impulse to fire. Plug it in, crank the engine over, it should flash really fast as the engine turns over. If it flashes reallllllllly slow, I would bet money on the temp sensor, cause thats what mine was doing. If its not flashing at all......Not really sure, could be the temp sensor, computer, oil pressure sensor....Something along those lines.
     
  13. readymix

    readymix 3/4 ton status

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    If it is not flashing it could be
    - Pick up coil
    - Ignition module
    - Wiring
    - ECM
     

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