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Thread: It appears I have a fuel pressure issue...maybe....

  1. #1
    Fuel Injected!
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    It appears I have a fuel pressure issue...maybe....

    The fuel pump I installed is a Precision fuel pump part number E16081 which is a cross for the airtex E3540 fuel pump.

    The airtex pump is rated for 12psi and 35gph.

    I bought one of the MrGasket fuel pressure gauges and installed that inline to check the pressure going into the throttle body.

    Started the truck up and the gauge is bouncing between 3-5 psi.

    I do have the gauge installed on the line that goes into the left larger fitting, the inlet, so I am kind of baffled at the moment what might be going on. I don't think the line is clogged.

    This probably explains the lean condition I am having at the higher rpm's in my other post.

    Wrong pump maybe?

    Could using about 2 feet of rubber fuel line rated for 50psi be an issue?

    Any thoughts?

  2. #2
    EFI GearHead ! EagleMark's Avatar
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    Pretty sure that is a diesel pump to supply the high pressure pump?

    Pinch your return line and see if pressure goes up? Either way the right pump would be better.

    There's some pump pictures and part numbers on this page.
    http://www.gearhead-efi.com/gm-ecm-p...onversion.html

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  3. #3
    Fuel Injected!
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    The part number E16081 on the oreilly auto page does show this pump used on chevy/gmc diesel and gas fuel injected engines.

    I am wondering if the hose I am using is adding to the loss as the hose seems more rubbery than normal, if that makes sense.

    I googled all the numbers on the page you linked and those numbers are pumps running about the 100psi range.

    It just dawned on me that I probably need to have a pump somewhere about the 45 psi range since the throttle body has the built in regulator. Is that thinking correct?
    Last edited by damanx; 03-12-2013 at 10:35 PM.

  4. #4
    EFI GearHead ! EagleMark's Avatar
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    That page is correct pumps for TBI and some may be for TPI. I have used TPI pumps for more flow in bigger engines but they will still run 13-15 PSI with regulator. 100PSI capability is never used because of the return flow from regulator, but the flow is correct. If you ever run one and it's 13 PSI and take off the return line there's not much coming out, no pressure on return line. It's all in the volume.

    IIRC the pump you have is like an electric pump for a carb, no return line. Carb electric pump just stops when it hits 3-8 PSI depending on pump. EFI pumps run constant.

    You should have metal or EFI rated rubber hose after pump to TBI.

    Your trying to reinvent the wheel...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  5. #5
    Fuel Injected!
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    Well, after some google-fu......I found that Federal-Mogul makes some of the Precision brand pumps and that the pump I currently have is rated 9psi max.

    Sheese....

    The pump I am going to try is the Precision E16116 which is rated for 9-22 psi.

    I've modded a pod for the adjustable regulator, but want to put that on after I get the fuel pump issue situated.

    Thanks for your help Mark.

    (wasn't trying to reinvent the wheel....lol)

  6. #6
    EFI GearHead ! EagleMark's Avatar
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    That looks like the Carter pump I always run as an external, also fooled me when my son brought it home from work and it was not a carter. It did work well!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  7. #7
    Fuel Injected!
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    Got the pump installed.

    MUCH BETTER!

    Pressure now bouncing about a 1/2 lb at 13.5 psi. Idle spray pattern is a nice cone shape.

    I suppose I am going to have to tweak the idle speed again seems the idle jumped up to about 1k.

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