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Running Out Of Gas

Discussion in 'Early CJ5 and CJ6 Tech' started by jzeber, Jul 5, 2019.

  1. Sep 11, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    I had an issue with my ‘64 ford dump over the summer that was similarly frustrating. Full tank but starving for fuel. It turned out the fuel pickup line that enters the top of the tank has a leak somewhere in the tank (most likely around the fitting?) and it was sucking air. The lower the gas level, the more suction it required, the more air it would draw in. I finally figured it out when I put a clear fuel filter in-line and could see the air being pumped in.

    I’ve had a gas can strapped in the passengers seat ever since. I’m still trying to figure out how I’m going to address it that doesn’t involve a new tank.
     
  2. Sep 11, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Fiberglas patch? It has worked for me when I could get the area of the leak very clean.
     
  3. Sep 11, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    It’s a leak inside the tank where the steel line is welded or pressed into(?) to the bung that’s part of the tank. Short of cutting it out to fix it and welding it back in, I don’t really see a fix.
     
  4. Sep 11, 2019
    45es

    45es Active Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Naches, WA
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    Use a bulkhead fitting that is slightly larger than your existing bung. Fab new pickup line and insert through bulkhead fitting.
     
    Daily Double likes this.
  5. Sep 22, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    I dropped the tank, pick up looked good. I checked and tightened all the hoses. Drove it today and it started right up. Drive 1/4 mile from the house and up hill, starved for gas and stalled. I coasted back wards and got it turned around. Bump started and drove it home. I added 4 gallons of gad and drove around the block up another hill and it died again on flat ground. Would not restart. Is it possible the fuel pump is only working intermittently? I pulled the fuel line at the carb and cranked it over, no fuel. Removed the pump and it works on the bench. I'm at my wit's end. I also made sure the lines were hooked up correctly. I have the smog fuel cannisters in back by the tank. I am not sure how that is supposed to be plumbed. 5 fittings.
     
    Last edited: Sep 23, 2019
  6. Sep 22, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Cap not venting? I assume you looked in the tank but couldn't see a problem. Check valves can stick in the fuel pump...tried Sea Foam in the tank? I think we'll all agree when stuff sits problems start showing up. I end up with my share of them.
     
  7. Sep 22, 2019
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

    USA
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    Well, assuming all your plumbing is correct, fuel pump crapping out? Cheap part to throw at it.
     
    45es likes this.
  8. Sep 22, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Can you tap on the fuel pump with a soft (plastic) hammer?
     
  9. Sep 22, 2019
    45es

    45es Active Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Naches, WA
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    Check the condition of the flex lines such as the one between the hard line at frame and fuel pump. Could be decaying internally causing a fuel blockage.
     
    47v6 likes this.
  10. Sep 22, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Thanks everyone, all great ideas. I'll report back
     
  11. Sep 23, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Going to order a new pump today. Should be here Weds. I was supposed to leave Friday for a trip.
     
  12. Sep 23, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    I have it out and on the bench and it seems to work fine. Ran some gas through it by hand.
     
  13. Sep 23, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    I did not think about the cap. Cheap enough to get a new one probably.
     
  14. Sep 23, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I've had mine not work and tapping on them has been the fix. It doesn't take much for a check valve to not function properly. Since you have a new pump on the way maybe it will be the fix.
     
    jzeber likes this.
  15. Sep 23, 2019
    Alan28

    Alan28 Well-Known Member 2022 Sponsor

    Châtillon en...
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    I have a fuel pump with a hand lever to action it and it helps. Always better to stay simple!
     
  16. Sep 23, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Did I mention it seems to run better when the tank is above 1/2 full or so.
     
  17. Sep 23, 2019
    Lee Bennett

    Lee Bennett Banned

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    Just a thought - maybe the fuel pump isn't strong enough to pull fuel from lower in the tank. Even differences in ambient air pressure can affect that.
     
  18. Sep 23, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    That is a thought and it used to run completely dry. Maybe the fuel pump is dying. It is a little over a year old.
     
  19. Sep 23, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    If it sat for a while it might have done exactly that. You said it works on the bench though....seems you would have noticed if it seemed hard to actuate.
     
  20. Sep 23, 2019
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Anyone have a diagram for the evaporative canister for a 71? I have found 72-73 but nothing for prior years. 5 fittings.
     
    Last edited: Sep 23, 2019
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