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help needed this is killing me

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by fright89, Mar 16, 2003.

  1. fright89

    fright89 1/2 ton status

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    This is really starting to get to me. I have been trying to figure this out for a while with no luck. In short the truck will not start. You can see a previous post describing the problem .here

    What I know

    I am not getting power to the fuel pump. As described before it is an electric pump mounted out of the tank. It is very loud and I can here when it works.

    What I have done

    Replaced the fuel pump really, coil, distributor/ignition module, checked wiring harness and grounds, checked ecm and ecm2 fuses.
    I could not get my oil pressure switch out and have not found a replacement that looks the same. I did try to by pass it by grounding the wire to it out.

    Stupid questions

    Is there a fuse for the fuel pump? Where is it?
    The manual says in the under hood electrical center. The blazer is a 1989, I don’t seem to have an under the hood electrical center.

    I am not to good with electrical problems.
    Where is the first place I should check for power to the fuel pump? It really seems I am not getting it to the relay.

    Would it be easer to check it from the pump back?

    Any other little bolt on that could be killing me?

    I usually only have one day a week to work on it and I have already missed out on a couple weekends out in the truck.

    Any more help appreciated, thanks
     
  2. manyblazers

    manyblazers Registered Member

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    Did you run a power wire direct from the battery to the pump to see if it is actualy working?
     
  3. Z3PR

    Z3PR Banned

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    I'd do 2 thing first of all. Use a test light to see if the pump is getting power. I'd also try running a wire from the posi. side of the batt. to the posi side of the pump. Gotta check to make sure you don't have a bad pump. If pump is good, just not getting power, run cheater wire to pump from switchable sorce at fuce pump. It'll get you runing till you can find the real problem.
     
  4. R72K5

    R72K5 Banned

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    do trucks have fuel pump fuse located in fender front like cars do ? i think its orange wire- decent sized one,

    external electric pump ? aftermarket ? year of truck ?
     
  5. fright89

    fright89 1/2 ton status

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    i did jump power to the pump and it works ok. its all original
    wiring just changed the location of pump. 1989 tbi
     
  6. BlaznRebel

    BlaznRebel 1/2 ton status

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    put a toggle switch on it and be done with it. I have driven several cars with a toggle and we never had any probs.
     
  7. DUKE

    DUKE 1/2 ton status

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    toggles are great untill your center console looks like this. [​IMG]
    actually it is cool, looks like a airplane. At least a theft wouldnt know where to begin
     
  8. BIG*RED

    BIG*RED 1/2 ton status

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    I have a holly red fuel pump..mounted to the frame just outside the tank..first off the pump needs to be as close to the gas tank as possible..electric fuel pumps are pushers not pullers..so the closer the better..as for wiring..mine is grounded right to the frame where it is mounted and the power wire i ran to my ignition..when the key is on the pump is on..i have never had any problems with this setup
     
  9. fright89

    fright89 1/2 ton status

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    the pump is a mallory mounted just outside the tank on the frame. the pump tests ok. it does work. i would like to find out whats wrong but i think i will wire it like yours or with a switch for now. it will probably stay that way forever.


    thanks everyody for the help tonight
     
  10. NewK5Guy

    NewK5Guy 1/2 ton status

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    Running an external pump, make sure the pump is mounted below the tank level so gas will not siphon back into the tank. Also, make sure the pump is mounted in the right orientation. Some pumps don't like being mounted upside down. Also, there is an inlet and outlet. Make sure the fuel lines are hooked up accordingly. Simple stuff, really, but it's the simple things that kill you.
    Pull the outlet hose and see if the pump is pumping gas to begin with. Just make sure there's a catch can for the gas coming out.
    Also, I bought(but didn't use) an electric pump for my diesel and the instructions stated taht it had to be mounted at at least a 45 degree angle with the outlet pointed up. I don't know how your pump is arranged, but it may make a difference. You clearly stated the pump runs so take a second to see if actually pumping anything. Clogged filter down the line maybe? If the pump is running and pumping, maybe the timing is off from when you changed stuff in the distributer.
    I'm just trying to name things you may have not thought of yet.
    A stupid little thing like this on my diesel cost me $446 recently. Trust me, it has to be something simple.
     

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