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Fuel Pump Check Valve Question

Discussion in 'Technical Q&A' started by zeiglerr, Nov 14, 2009.

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  1. zeiglerr

    zeiglerr Karting

    Oct 23, 2009
    69
    Lansdale, PA
    Full Name:
    Reid Z.
    #1 zeiglerr, Nov 14, 2009
    I've been chasing down a hot start problem on an '81 Mondial 8. I did a pressure test at the WUR and the fuel lines lose pressure immediately when the key is turned off. I've checked for injector leaks, including the cold start injector and all are fine, so I bought a new fuel accumulator. In installing it today, I noticed that there is no check valve at the exit from the fuel pump. I didn't remove the fuel pump yet to see if it's a Bosch, but is the check valve internal, or in the brass fitting to the delivery pipe? (this one is a straight through hollow fitting with no check valve external to the pump) Thanks -Reid
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,931
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, Nov 14, 2009
    Last edited: Nov 14, 2009
    On the early K-Jet fuel pumps (like on your car), the check valve was a non-replaceable unit built into the outlet fitting of the fuel pump itself (so when the check valve went bad the whole pump had to be replaced:
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    These early style pumps are no longer available so you'll have to change to the later style K/KE-Jet pump that has the screw-in replaceable check valve and uses a banjo fitting and flexible fuel line connection. The Boxer guys have the same dilemma, and here are some photo's from P. Newman's project to update his Boxer. Contact Larry Fletcher (fletch62) -- he runs a small company dealing with the K/KE-Jet components and can get you the parts needed to update to the later style pump/check valve:
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    512BBi fuel assembly with early pump w/non-replaceable check valve, union fitting, and hard line:
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    512BBi fuel assembly with later pump w/replaceable check valve, banjo fitting, and flexible line:
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  3. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    29,253
    socal
    #3 fatbillybob, Nov 14, 2009
    alternatively it could be cheaper to install a check valve as close to the pump outlet as possible and that will likely work for you. The hard part is not that hard just figuring out what plumbing you will need.
     
  4. zeiglerr

    zeiglerr Karting

    Oct 23, 2009
    69
    Lansdale, PA
    Full Name:
    Reid Z.
    #4 zeiglerr, Nov 14, 2009
    This is great! Exactly what I needed. I'll take another look tomorrow and decide which way to go. -Reid
     

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