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sputtering and dying at high RPM

Discussion in 'Intermediate CJ-5/6/7/8' started by ndh87, Jul 1, 2007.

  1. ndh87

    ndh87 Does it run?

    I've got a 258, still running points and condenser. It idles fine, and revs up ok when its sitting still, but when i try to drive up the hill to the gas station it starts to sputter and cut out. Any ideas whats going on here? i have about 2 and a half gallons in the tank.
     
  2. 73cj5

    73cj5 Member

    Id say you your fuel pickup is coming uncovered. Put more gas in it and then try.
     
  3. JCs

    JCs New Member

    My Cj6 was doing that. I had a hole in the pickup line at about 3/4 of a tank. If I went up hill it would stall, if I could get it pointing it would run for a couple of miles then run out of gas.
     
  4. trickpatrick

    trickpatrick Done? LOL

    Lots of times its pluged up sock filter in the tank that causes that.

    Works fine until you need a higher flow of gas, uphill or under load, ect.
     
  5. jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Sounds a little like vac leak, too. Fill it up with gas and see if it still does it.
     
  6. NorCoJeeper

    NorCoJeeper Member

    If it cuts out on level ground as well it could also be a plugged fuel filter.
     
  7. ndh87

    ndh87 Does it run?

    ok, i tried adding more gas. its still doing the same thing. as long as its sitting still it idles and revs fine but once i start moving it cuts out. After it stalls out it wont restart until it has sat for about 5 mins without trying to start it. after about 5 mins it starts right up.

    right now i have the tank bolted in, and I'm using 5/16 rubber flex line from the tank to the fuel pump, and from the pump to the carb.

    could it be that my fuel line is too large a diameter for the pump to handle?

    Before i put the tank in i drained the old gas out, and the fuel filter looked pretty new.
     
  8. farfle

    farfle old dog

    Thats a whole lotta rubber line. You could be colapsing the line. I think thats one of the reasons the factory ran steel for any length. I was always taught that you should keep the rubber line limited to just a short section or two where you really need flex.
     
  9. jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Again, it sounds like vac leak.
     
  10. ndh87

    ndh87 Does it run?

    What do you mean by a vac leak?
     
  11. 1960willyscj5

    1960willyscj5 Well-Known Member

    One of your 'friends' sneak by and drop a ping-pong ball into your tank when you weren't looking?:twisted:
     
  12. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Vacuum leak. Air is leaking in due to engine vacuum say around the base of the carburetor, where the intake manifold meets the head, or from an open vacuum port, among others.
     
  13. ndh87

    ndh87 Does it run?

    anyone know where to find a vac tube diagram? (besides haynes)