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What to use for fuel line connection electric pump to carb?

Discussion in 'The Garage' started by Skigirl, Jun 15, 2006.

  1. Skigirl

    Skigirl 1/2 ton status

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    Taking the mechanical fuel pump off, already have an electric pump installed. There's more pressure with the electric pump and I think the rubber hose wouldn't stand up to the added pressure for long. Am I correct thinking this?

    What do you use to connect the hard fuel line from where the mechanical pump was to the hard lines going to the carb? More hard line? Some kind of re-enforced fuel line like a stainless steel flexible line?

    TIA!
     
    Last edited: Jun 15, 2006
  2. Cricket

    Cricket 3/4 ton status

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    Do you know what kind of pressure your pushing, what type of pump is it?

    I've got small sections of rubber line in my TBI loop and no problems. The rest I used stainless brake line and fittings.
     
  3. Skigirl

    Skigirl 1/2 ton status

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    It's an Airtex E8012S. 5.5 - 9 PSI
     
  4. berserker

    berserker 1/2 ton status

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    no worries

    i wouldn't worry about it just use some 3/8 fuel line with some hose clamps and you'll be fine for carb. usually 4 1/2-8 psi. they sell fuel injection rubber hose that holds 90-120 psi not very positive but i would use that for fuel injection. i use to run a holley blue with about a foot of rubber fuel line then switched back to mechanical because i burned up the holley. hope that helps.:wink1: make sure u get a pressure regulator holleys and demon carbs usually around 7psi carter edelbrock rochester around 5psi don't run to much or you'll flood the floats.
     
  5. steve_kibbe

    steve_kibbe 1/2 ton status

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    6-8 psi won't ruin regular fuel line.

    Where are you locating the pump? If its by the tank/fuel cell, I would either hard use hard line or stainless though. But if its in the engine compartment, I'd just use regular rubber fuel line, unless you have some stainless around.
     
  6. goldwing2000

    goldwing2000 Guest

    Your local parts store should have both rubber fuel hose and rubber fuel injection hose. The fuel injection hose is reinforced.

    Try to use less than 12" of it. If you need more than 12", splice in a piece of hard line or use stainless-reinforced flexible tubing.
     
  7. Skigirl

    Skigirl 1/2 ton status

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    Thanks guys. The electric pump is back by the tank. Not sure how I'll run the hard line from where the mechanical pump will be gone to the carb - I'm thinking the best idea is to move / cut the hard line before it passes next to the exhaust manifold (as I'm trying to solve the vapor lock prob and this run is part of it) run stainless vertically by the firewall then attach to the carb at that point. So I may need to run more than 12" of line, so stainless it is (unless I can actually get away with FI fuel ine).

    Good idea on the pressure regulator too. It's an Edlebrock carb. I do have a couple more questions tho...

    1. If the fuel pump puts out 5.5 - 9 PSI and the carb needs 5 PSI, is that enough of a difference to require a pressure regulator? I have no problem adding one - looked at the Edelbrock 1727. Adjustable from 5- 10 PSI. But it has 1/2" NPT inlet and outlet. How do you connect that to the hard line (which is 5/16ths?)

    2. Do I just cap off the return line from the mechanical fuel pump to the gas tank? If so, what do I use to cap it off?

    3. If for some reason I need the return fuel line how the hell do ya do that plumbing?

    Thanks again for the quick responses. Love you guys!
     
    Last edited: Jun 15, 2006
  8. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    I'm pretty sure you'll need a regulator. It'll bypass fuel which will return to the tank via your old return line. Regultor fittings like the npt ones are easy to get spigot fittings for. Just screw the fitting to the unit then push your rubber hose onto the spigot and secure it with a jubilee clip.
     
  9. Skigirl

    Skigirl 1/2 ton status

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    Mark - a little confused - the pressure regulators I looked at on line had one inlet / one output npt, which I assume is to be placed between the electric fuel pump and the carb. How does the return line plumb into this?

    OK, nevermind, I see. Searched the net for a bit, there are pressure regulators that have a return line hookup.

    Will have another question about EVAP cannister in a minute... stay tuned.

    Thanks Mark.
     
    Last edited: Jun 15, 2006
  10. steve_kibbe

    steve_kibbe 1/2 ton status

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    I don't think carb'd engines have return lines, only fuel injection.

    You don't need to worry about a return line, just get a regulator with a guage and call it done:D
     
  11. Skigirl

    Skigirl 1/2 ton status

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    Steve, it definitely has a return line. Wish it didn't...
     
  12. steve_kibbe

    steve_kibbe 1/2 ton status

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    :blush: Back to the drawing board.:thinking:
     
  13. Skigirl

    Skigirl 1/2 ton status

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    K, looks like I found a regulator with a return line: regulator

    What do you all think?
     
  14. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Looks good to me. I knew '78s had a return as factory from the mechanical pump but didn't realize yours did. It's a good thing though as it'll make life easier for your pump. You'll have to play about with the pressure setting a bit as it's good to have a bit of extra pressure for higher revs and WOT stuff but high pressure at low revs can often overwhelm the float needle and make you run very rich. Not sure what carb you're running but if there is a sprung float needle option available for it, fit it while you're doing all this work. They really help smooth out fuel feed when the going gets a bit jiggly!:D
     
  15. steve_kibbe

    steve_kibbe 1/2 ton status

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    Looks like that will work:D
     
  16. Skigirl

    Skigirl 1/2 ton status

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    Good idea. I'll check. I have an Edelbrock 1406.
     
  17. Skigirl

    Skigirl 1/2 ton status

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    I will, thanks jms!
     

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