250 fuel pressure

Discussion in 'General Maverick/Comet' started by Wutend, Jun 8, 2024.

  1. Wutend

    Wutend Member

    Joined:
    Jul 9, 2022
    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    12
    Location:
    Ohio
    Vehicle:
    74 maverick grabber
    So I've installed a fuel pressure gauge in my 74 mav with a 250 and it's reading very low. I'll start the car and the pressure with sit around 5psi then after a few minutes it will drop to around 2psi. I've tried another gauge and same thing. I can feel the pump working and I can see it pull fuel into the prepump filter I have, be it rather slowly in my opinion. Could the pump be slowly dying? It is the original. Also engine starts to sputter a bit once the pressure starts to drop. Any thoughts would be great. Thanks
     
  2. Powerband

    Powerband Member

    Joined:
    Nov 6, 2014
    Messages:
    439
    Likes Received:
    184
    Trophy Points:
    128
    Garage:
    1
    Location:
    NY's \H/
    Vehicle:
    ---- 1976 Comet --- 1974 Maverick- - '61 Comet T'Bolt Six ---- 'quite a few projects ...
    where does gauge tap fuel line?.
    .
    once fuel bowl is full at idle, filter flow slows dramatically but pressure should not. does pressure rise when engine is accelerated? , it should... .
    .
    also:
    "... engine sputters a bit once pressure starts to drop... " - MAYBE drops when carb is simply opening up fuel bowl needle valve or even could be flooding engine, which would drop pressure.
    .
    new pump may give same results - then you have a spare .
    .

    hav fun
     
  3. Wutend

    Wutend Member

    Joined:
    Jul 9, 2022
    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    12
    Location:
    Ohio
    Vehicle:
    74 maverick grabber
    The gauge is right in front of the carb. The pressure doesn't change with revs. I've read that once these gauges get hot the reading will be off which kinda makes some sense. Once I shut the engine off the pressure slowly goes back up then eventually drops to 0 once the engine cools. I'm kinda at a loss with this one.
     
  4. Krazy Comet

    Krazy Comet Tom

    Joined:
    Sep 13, 2012
    Messages:
    7,589
    Likes Received:
    2,346
    Trophy Points:
    531
    Garage:
    1
    Location:
    Chesapeake VA
    Vehicle:
    1972 Comet GT clone 306 . 1969 Fairlane Cobra 428CJ 1988 T-Bird awaiting 331 ..
    Most fuel pumps were falling at 10-15 years, draw your own conclusion
     
  5. 71gold

    71gold Frank Cooper Supporting Member

    Joined:
    Apr 9, 2002
    Messages:
    26,483
    Likes Received:
    2,849
    Trophy Points:
    978
    Garage:
    1
    Location:
    MACON,GA.
    Vehicle:
    '73 Grabber
    Jeff has the opposite problem. his new pump would peg his 25 PSI gauge. He took the pump back and got another one that did the same thing.
     

Share This Page