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Frame mounted fuel pump location

Discussion in 'The Garage' started by Mastiff, Jun 20, 2004.

  1. Mastiff

    Mastiff 1/2 ton status Premium Member

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    I'm converting from carb to TBI and using a frame mounted electric fuel pump. I mounted it in a convenient low place on the frame, but now I'm being told that maybe it's too far from the tank?

    Does it really matter? It doesn't seem like it's any harder for a pump to pull fuel through a line than it is to push it, is it?

    Also, does it matter if the pump is high or low relative to the tank? I opted for low, but to get closer I'd have to go higher, like up above the rear axle. It seems like that could be bad sometimes, like the pump would have to suck air for a while before getting gas. At the low place it gets constant siphon action.
     
  2. i_4x4

    i_4x4 1/2 ton status

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    I just did a Vortec swap last month. When I got my external pump, they told me to mount as low & as close as possible. Guessing it is even w/ the bottom of tank & about 3 1/2 ft forward. This is where the arch on the frame meets flat frame rail going forward. Works great so far. Also after install & running, if it runs overly RICH. Your return has to much restriction. Mine I messed w/ 1 1/2 weeks before this was found to be the culprit. (Thanks Tim) /forums/images/graemlins/thumb.gif. If this might be the case, extend the return line into fill neck. It instantly fixed my problem. Hope this helps. Ed /forums/images/graemlins/usaflag.gif
     
  3. Mastiff

    Mastiff 1/2 ton status Premium Member

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    In my case, I'm way, way too lean. The guy I bought the kit from wants to blame it on the pump being too far from the tank. I can go maybe 18" further back and still be on the low part of the frame rail. He hasn't said whether closeness is more important than height or what.

    I put it further forward just because I wanted to take advantage of the place where the steel line already broke to go into the small section of rubber line. If I go back I'll have to cut the steel line somehow. I'm not sure how to do this while gas is dumping out all over. /forums/images/graemlins/dunno.gif

    I really don't want to do it over again anyway if I don't need to since it was the worst part of the whole job, and I'll need to get all new rubber fuel line.
     
  4. HarryH3

    HarryH3 1 ton status Author

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    I mounted mine directly above the rear axle, to keep it well up out of harms way. It never has a problem priming. /forums/images/graemlins/cool.gif
     
  5. Mastiff

    Mastiff 1/2 ton status Premium Member

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    [ QUOTE ]
    I mounted mine directly above the rear axle, to keep it well up out of harms way. It never has a problem priming. /forums/images/graemlins/cool.gif

    [/ QUOTE ]

    /forums/images/graemlins/thinking.gif The Holley pumps specifically say to mount them below tank level. I wonder if there's something unusual about them?

    How do you have your filtering set up? Do you have a filter before the pump, or a high pressure filter after the pump? Right now I have a cheapo purolator filter before the pump, but I wonder if it's causing any restriction.
     
  6. Mastiff

    Mastiff 1/2 ton status Premium Member

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    What kind of fuel line did you guys use from the pump to TB and back to the tank? My kit came with 3/8" 250psi rubber hose, but if I have to move the pump, I won't have enough anymore. I doubt the local parts shop has this super thick stuff.

    Oh, and how about filtering. I asked this someplace else on this forum, but I forget where. Right now I have a low pressure filter before the pump - which seems like a good idea, to protect it from crud. If I look in my Summit catalog though, they really push the high pressure filters for some reason. I have a run-of-the-mill purolator filter on there right now. I hope it's not causing a restriction.
     
  7. HarryH3

    HarryH3 1 ton status Author

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    I put a new sock filter on the pickup in the tank and have a GM factory inline fuel filter after the pump. /forums/images/graemlins/cool.gif
     

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