rough running, about to sputter out

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by stonefly4, Nov 10, 2019.

  1. lwlevens

    lwlevens Medium Load Member

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  2. swaan

    swaan Road Train Member

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    It wont pressure build up. It will be a vacume causing the engine to starve for fuel. As the engine burns fuel the void needs to be replaced by air . If air cant get into the tanks it creates a vacume.
     
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  3. stonefly4

    stonefly4 Light Load Member

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    I wish I would have had a fuel pressure gauge.

    There is another matter. The tanks were at half full or less, which means that there was a lot of air. Temperatures varied widely from day to night and back to day. This would cause the air in the tanks to undergo pressure changes. If the fuel caps did not allow these pressure changes to equalize, this could have been the source of the problem.
     
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  4. Rideandrepair

    Rideandrepair Road Train Member

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    A vent on each tank, would have done the trick. You proved it by drilling the holes. A fitting tapped in, with a hose attached, wouldn’t hurt, at this point, extra vent.
     
  5. Rideandrepair

    Rideandrepair Road Train Member

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    Now mines been doing it, since the Overhaul. Changed check valve. Seems to be holding prime now, but after idling a little while, while winding up, it shudders and blows white smoke. Till it catches on. I changed fuel filters, See if that helps. It’s acting like it’s sucking air. I suspect the shutoffs on tanks. Going to eliminate that valve, altogether. And replace the lines from tank to pump, and pump if I have to, it’s only 4 yrs old.
     
  6. Rideandrepair

    Rideandrepair Road Train Member

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    Changed fuel filters, problem fixed. I thought they were almost new, thought I had a problem, whew!!
     
  7. Y-L

    Y-L Light Load Member

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    Could this problem happen if you have vented fuel caps?
     
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  8. BUMBACLADWAR

    BUMBACLADWAR Road Train Member

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    Oh Geez. I would Probably get some heavy fuel system/ injector cleaner like l Lucas or Redline if they have it for diesel and algae cleaner and just keep on with frequent fuel filter changes .JMO
     
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  9. Rideandrepair

    Rideandrepair Road Train Member

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    Mines sucking air, only sputters occasionally, after idling, while winding up. I suspect the fuel tank shutoff valves, or a hose between tank and pump. Has to be, Will know soon enough, right now, got to run, as much as I can, after 5 weeks Downtime.
     
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