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hot fuel module??

Discussion in 'The Garage' started by DFR, Nov 6, 2005.

  1. DFR

    DFR Registered Member

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    g.m. wiring diagram shows a hot fuel module in the circuit for a 87 350 tbi truck, what is this and where is it located????
     
  2. blazerguy 90

    blazerguy 90 1/2 ton status

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    Im going to guess they mean the fuel pump relay, its located above the distributor and to right on the fire wall. thats my guess anyway, if this is something let us know.
     
  3. neverendingproject

    neverendingproject 1/2 ton status

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    If you are talking about the thing under the dash in the diagram or near guage cluster....

    ***DO NOT TRY AND FIND IT OR PUT IT ON***

    anyways, dont worry about it, its not for the 350. I had the same problem when retrofitting my 84 with TBI and the gm guys say its only 7.4L (454) equipped vehicles. It caused me whole bunch of headaches and come to find out, we dont need it.
     
  4. DFR

    DFR Registered Member

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    Thanks, but no relay is different from module according to diagram, this module is suppose to have 3 wires coming from it, I am not getting power to fuel circuit, but truck will run if gas is poured down throttle body
     
  5. neverendingproject

    neverendingproject 1/2 ton status

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    Yes, I had the same problem. you need to hook up a wire from the battery to the alt, to the junction block, because your injector cicuit is not getting power.
     
  6. DFR

    DFR Registered Member

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    could you be more specific where you went to fuse block, and what wire you went off alt.?
     
  7. neverendingproject

    neverendingproject 1/2 ton status

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    I will try to explain in detail, but I dont want to act condecending.

    2 Wires come off the battery
    1. goes to starter
    2. goes to alt.

    from the power wire off the alt. go to the power junction block that is represented by the blue box under the arrow. From the juntion block, a wire goes to the heater, and the other goes across your booster to your harness hub in the firewall. This provides power to your circuit that has no power, which includes ecm A and ecm B.

    This is what the problem was in my case. Hope this helps

    Also, are you retro-fitting TBI into youir vehicle or has it just stopped working?

    wire1.JPG
     
  8. jays68yak

    jays68yak 1/2 ton status

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    I just retrofitted mine and was also not getting power to the injectors. Make sure you have both pink/black stripped wires hooked up to power. I only had one for the ecm and missed the injector power wire. Once I hooked that up it worked fine.
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Just to clarify, it isn't getting power when you first turn the key to run? You can't hear the pump run for a couple of seconds in other words?

    On the TBI relays, (and ALDL) you can force the fuel pump to run, depending on how the hot fuel module is wired, does that test work? With the forced pump operation, it would make sense that the hot fuel module would be bypassed.

    Do you have a link to the diagram you are using, or are you dealing with a hard copy? I'm curious to see how they wired it.
     

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