cat 3406b -fuel transfer pump problems?

Discussion in 'Trucks [ Eighteen Wheelers ]' started by dairyman, Dec 21, 2010.

  1. SmokinCAT

    SmokinCAT Road Train Member

    No, I never did have any trouble with it loosing prime, and now I run an electric pump to keep up with the pressure and flow I needed. Since it is still doing it you might look over your fuel lines, check all your fittings. I think les is probably right though, I'd say a check valve has went bad some where in the system.

    If your worried about the pressure go buy a cheap mechanical pressure gauge, oil will be the most common type, there should be a plug on top of your factory fuel filter base, that's where you will want to check your pressure, you should have no less than 40psi under power.
    dairyman and Eighterfromdecatur Thank this.
  2. Eighterfromdecatur

    Eighterfromdecatur Bobtail Member

    Apr 10, 2012
    Decatur TX
    My b model is acting up in a similar fashion. Doing everything yours is but isn't loosing prime. I've changed filters replaced the main fuel lines with no avail. I've got 40 psi idiling I was leaning towards the lift pump but w that pressure I'm stumped. I'm going to check my check valves this afternoon. My fuel/water seperator is dry also, you can take it off the truck and it continues to run fine. Good luck with your trouble shooting, Im looking forward to seeing the end result.
  3. little cat 500

    little cat 500 Road Train Member

    Jan 17, 2010
    Abbottstown PA
    i didn't think a 3406b had a check valve just a # 4 fitting on the return i guess there is a check valve in the lift pump sounds like a loose fitting to me
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