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Electric fuel pump as a pusher....

Discussion in 'The Garage' started by SUBFAN, Aug 1, 2005.

  1. SUBFAN

    SUBFAN 1/2 ton status

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    What are the thoughts on using the stock TBI fuel pump as a pusher for a mechanical pump?

    Will the mechanical pump act as a regulater of sorts to keep the pressures reasonable?

    I know this tends to burn up the electric pump, but using a mech. pump with a return might help alleviate this problem.

    The plan is in the future, when the electric pump fails, I would modify it to just run off the mechanical pump. Any info on this modification?
     
  2. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    The mechanical pump won't suck through the electric one when it fails.

    The mechanical pump might not like seeing pressure to its inputs. I know it'll burn up some electric pumps but I assume worst case with a mechanical pump it'll just blow the diaphragm that much faster.

    That being said, I won't ever run a mechanical pump. One too many crankcases full of gasoline.
     
  3. njkrause

    njkrause Registered Member

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    One of my dad's trucks was set up that way. We ran an electric pump as a pusher on a wide open throttle switch so that it only ran at wot. Worked well for many years, 8+, before having to replace the mechanical pump. This truck was not a daily driver and sat most of the year though.
     
  4. SUBFAN

    SUBFAN 1/2 ton status

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    Do you regulate the electric pumps? Any pics?

    I have purchased a regulater with a return, but I am kind of concerned with the extra routing of fuel lines that is required.

    Just trying to keep it simple....
     
  5. txfiremank5

    txfiremank5 1/2 ton status

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    On my 77 pu I used an aftermarket fuel pump with the mechanical still hooked up and it work in that set up. I was having trouble with a vapor lock problem that would not go away with all sort of tries, so that was my final result. I ran it for years that way. Years later when I rebuilt the engine, my cam shaft was nearly worn in 2 where the mech pump rod must have gotten stuck or something... and the mechanical pump no longer worked either (especialy like that :rolleyes: ). It still ran fine like that.. I didn't know there was a problem until I tore it apart for the rebuild. After the rebuild I just blocked it off and went straight from the elec pump to the carb. That same elec pump last another few years, and then I replaced it in the early 90's, and it was still going in 99 when I sold it.

    Soo.. I think it would work just fine.. unless I just got really lucky.
     
  6. LongIslander26

    LongIslander26 1/2 ton status

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    Fuel Pump

    I would just run the electric pump with a return and a regulator, and eliminate the mechanical pump entirely, thereby eliminating the HP loss to the engine having to drive the pump.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    What are you dealing with that you'd want both pumps anyway, and would eventually just convert to mechanical?

    Unless 100% necessary, I wouldn't run two fuel pumps of any type, a regulator, or anything else, as it adds unnecessary complexity, which of course leads to unnecessary failure.

    If you want to upgrade a mechanical fuel pump setup, I say add in the fuel return line if it doesn't exist, which will eliminate any potential vapor lock issues.

    If you are doing something outside of the realm of "normal", then feel free to disregard my post. Heck, disregard it anyways if you wish. :wink1:
     

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