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Fuel Delivery Problem

Discussion in 'Truck & Equipment Repair' started by Effinay, Sep 6, 2011.

  1. Effinay

    Effinay Member
    Messages: 35

    Can't figure this one....Air bubbles were showing up in my glass fuel filter on my New Holland LB 480 to the point where it would sputter and stall. Someone here suggested looking for a ill fitting fuel line connection on the suction side of the fuel pump. Sure enough! Thought I found the problem when I discovered a splice made in the 3/8" line made with a 5/16" barbed connector. Changed it to a 3/8 connector, new hose clamps, done. Right!? Not so...same problem reappeared. Alright then, lets change the hose so there's no splice. Brand new line from the supply house, new clamps, half hour of cussin' and threading the new line in place, done. Right!? Not quite...Ran a test on the fitting and the pick-up tube in the tank and found no concerns, so it must be the fuel pump. Research and find a new pump, 45 minutes of cussin' and brusin' a knuckle or two and I got the thing in there, replumbed and ready to go. Sumbitch fires right up and runs like a champ. I thought I had a new tractor. Ran for a while and now I got the same problem I started with. Anyone got any suggestions? I could sure use some help with this.....Thanks.
     
  2. Woodenshoe

    Woodenshoe Member
    Messages: 84

    Sounds like there might be crud in the tank blocking the pickup (intermittently???) causing high suction, thus air bubbles. We went through this last year with one of our loaders, and we were sure it was other issues...
     
  3. Effinay

    Effinay Member
    Messages: 35

    fuel delivery problems

    Hello Shoe,
    Thanks for your response. Judging by the overall condition of this machine it may be a likely cause. Now that I think about it there are times when the engine speed fluctuates even though it's regulated by a vernier throttle control. I wa going to try and put a temporary fuel line directly into the fill cap and see if that makes a difference before I have to try and remove the tank. It's under the cab floor and not user friendly to access. Thanks again for your help and taking the time to respond.
    Regards,
    J-:salute:
     
  4. Woodenshoe

    Woodenshoe Member
    Messages: 84

    You can always run a temporary line into a can to troubleshoot...
     
  5. greywynd

    greywynd PlowSite.com Addict
    Messages: 1,343

    Sometimes the steel pickup lines will either rust enough to let air in, or crack (sometimes inside the tank too) and let air in.
     
  6. Spucel

    Spucel Senior Member
    Messages: 413

    Thats a good idea...should quickly rule out problems with the tank.
     
  7. csi.northcoast

    csi.northcoast Senior Member
    Messages: 320

    i had a similar problem with an int''l 4900 truck...see post...turns out that the fuel line was collapsing inside,... also crud in the fuel pump the truck would run great then would die ... hope this helps
     
  8. Effinay

    Effinay Member
    Messages: 35

    Thanks for the input guys. I McGivered an extension of the fuel line directly into the tank and only had time to run it for a few minutes. There's still a bubble visible in the filter, I was hoping that with an unobstructed line it would come gushing in and force the bubble through the system. Like I said, I only ran it a short time and only at idle just to see what was going to happen. I'm going to give it a run tomorrow. Thanks for the help and I'll let you know what I find.....
     
  9. Effinay

    Effinay Member
    Messages: 35

    Ran the loader for an hour or so using the auxillary hose and it ran fine. Great suggestions and can't thank you enough for your help. Now I just got to figure out how to put a new suction line in the tank to replace the problem child.....
     
  10. Woodenshoe

    Woodenshoe Member
    Messages: 84

    Glad to hear it, troubleshooting is sometimes the hardest part!
     
  11. Hoss4x4

    Hoss4x4 Member
    from FL
    Messages: 34

    This is a great test! You use it alot. It isolates the area. Just make sure you use enough fuel. Not sure how the fuel returns on that engine. Usually diesels return more fuel than they burn. Keep that is mind so you don't have to mess with bleeding the fuel system.