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Splicing wires inside a gas tank....

Discussion in 'The Garage' started by fad2blk99, Sep 26, 2004.

  1. fad2blk99

    fad2blk99 1/2 ton status

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    Is it suicide!?!?!?!
    I gotta break in the wires to my fuel pump inside the tank and I can't find a junkyard source for a replacement (I'm still looking). The dealer wants 400+ for a whole new sending unit, and I'm not even sure it comes w/ the in-tank portion of the harness.
    If I do have to splice it is there a way to do it safely? Are there shrink wraps that with stand fuel?
    Of course the danger is if by chance one of these connections come loose and create an arc... and KAABOOOM!!!
    All that being said I'd really rather not have to go that route.... /forums/images/graemlins/frown.gif

    Anyone gotta 3-wire 31gal sending unit for a Blazer/Jimmy/Sub for sale? /forums/images/graemlins/ears.gif
     
  2. hawkeye649

    hawkeye649 1/2 ton status

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    I have a 1985 K5 w/ 31 gallon tank.
    Would this be compatible? (Are you tbi...)
    My gauge stopped working, but it pegged over to the right so I think it's a ground problem and not a sender problem...

    GMC Gremlin
     
  3. fad2blk99

    fad2blk99 1/2 ton status

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    I'm TBI. It would have to be '88-'91.
    Thanks though.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    As I understand it, the ratio of air/fuel in the tank makes it impossible to have an explosion even with an ignition source. (maybe with no gas cap you could have problems?)

    Someone else can comment if they know more on that topic, but I had heard that is why in tank pumps are not dangerous in the first place.

    Curious to hear what can be used in your situation though...perhaps solder the wires then use fuel resistant silicone to "seal" it, if there is such a thing?
     
  5. TorkDSR

    TorkDSR 1/2 ton status

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    stoich in an engine is around 14 (right)... why wouldnt it be the same in the tank?
    thats for optimum combustion.
    so an empty tank would easily blow up.
    right?
     
  6. fad2blk99

    fad2blk99 1/2 ton status

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    I "think" it may be too rich of an evironment to ignite. /forums/images/graemlins/crazy.gif
    I'm not worried when the splices are covered by fuel-- its when the tank is close to empty, leaving more space to be occupied by air.
     
  7. fad2blk99

    fad2blk99 1/2 ton status

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    TWA flt 800 /forums/images/graemlins/crazy.gif.... and the flash point of today's jet fuel is higher than gasoline (similar to that of diesel fuel).
     
  8. surpip

    surpip 1 ton status

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    pm and e-mail sent /forums/images/graemlins/waytogo.gif
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Don't electric motors generate sparks by design?

    Anyways, thought it was maybe in the GM service manual, I couldn't find it if it is.

    I certainly wouldn't want to take chances with spark either where I didn't have to, thus, need to find something fuel resistant that can insulate the wire. I'd also look into zip-tying it away from the metal portion of the body for preventive measures, after repair, if possible.
     
  10. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    Just replace the whole wire down to wherever you're going with it. Solder it up, call it done.
     
  11. mosesburb

    mosesburb For Rent Premium Member GMOTM Winner

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    I created my own in-tank harness for a custom TBI conversion about 12 years ago by soldering and heat-shrinking the wires. It is still working today with no problems at all. PVC insulated wire does not hold up as well as cross-link polyethylene jacketed wire, but even the PVC will hold up for many years.

    BTW, the new sender will come with the harness, but doesn't come with the pump or strainer /forums/images/graemlins/frown.gif.
     
  12. springsgmc

    springsgmc Newbie

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    I used crimp on stud connectors and stuck the positive wire inside a piece of rubber fuel line to keep it from shorting against the pickup tube. So far, I haven't blown up.

    Previously, I tried shrink tubing and it disintegrated in the gas.
     
  13. fad2blk99

    fad2blk99 1/2 ton status

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    I was kinda figuring the shrink wrap wouldn't hold up.

    You be sure and let me know if you do blow up so I know to try something different... /forums/images/graemlins/yikes.gif (kidding)
     
  14. springsgmc

    springsgmc Newbie

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    What's your phone number? I'll put it on a speed-dial button. /forums/images/graemlins/deal.gif
     

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