big cam 290 cummins fuel pump help needed

Discussion in 'Trucks [ Eighteen Wheelers ]' started by earthmover, Jul 19, 2010.

  1. earthmover

    earthmover Medium Load Member

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    hay guys a buddy of mine has a 1972 gmc white with a big cam 290 cummins and he got low in fuel and the truck shut down ..now the truck started right back up and he got fuel init,now the truck runs good going down the road but when you stop it wants to go up and down idleing want stay steady....took pump off and cleaned all lines put new filters on still have the same thing...anybody have a idea of what this could be only other thing seems to be buy a new pump...could someone point him in the right way...thanks mike...also when he takes the filters off its not all the way full of fuel its about 2" from the top....
     
  2. Bush chook

    Bush chook Light Load Member

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    You,ve still got a restriction - did you clean the filter on top of the pump housing ( round plug -flat tip screw head 1" diameter ) or your sucking air
     
  3. earthmover

    earthmover Medium Load Member

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    hay thanks ill let my buddy know about the filter on top i dont think that he know it has 1 on the top...i fig. its sucking air aswell but he says he has checked everything and didnt find any problems....but thanks again ill keep you posted... seems as if when 1 has a problem it becomes a chain reaction ...i see hes not the only 1 with fuel problems
     
  4. Bush chook

    Bush chook Light Load Member

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    I.t,s a round brass gauze filter
     
  5. earthmover

    earthmover Medium Load Member

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    hay thanks bush chook we took it out and cleaned it(nobody had 1) and it helped but theres got to be a air leak so where...this think cranks up and runn fine for a min then start to running rough for a little but driven down the road it runs just like money...so thanks again mike
     
  6. albertaphil

    albertaphil Bobtail Member

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    Any luck with your 290 yet, earthmover? See my post...we have similar problems.

    Phil
     
  7. JohnP3

    JohnP3 Road Train Member

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    If you can see the return line into the fuel tank, see if it is blowing bubbles. It could need a valve set, or it could be sucking air. If the pump has a compucheck fitting on the back of the pump. Find someone with a vacume guage and see what the restriction is anything over about 7 with a clean filter means you have a restricted line, you will have a bleed line off the PT pump. Be sure it is not plugged.
     
  8. old-six-pack

    old-six-pack Heavy Load Member

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    got air in the system ,,old cummins good for this .. sucking air in pickup line put fuel in both tanks too:biggrin_25510: if all else fails,,,, hook another fuel line to the pump and drop it down in the filler hole in the fuel.. this test is to see if you are sucking air from your old lines.. need to drive several miles becaust it takes an old cummins some time to purge the air out... .. pickuptubes in tanks are famous for cracking too.
     
  9. earthmover

    earthmover Medium Load Member

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    hay guys my buddy replaced the line from the tank on driverside and still got a problem(i think its air in the line)he didnt do the 1 that runs to the other tank so ill pass on the info he really is going crazy with this problem...like i said it runs good going down the road and sittting still for a few mins. then itll go up and down then cut off (not all the time ) so thanks for the info ill pass it on mike
     
  10. albertaphil

    albertaphil Bobtail Member

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    It is an identical problem as mine, Mike. I doubt it is the crossover pipe from one tank to the other, as that line will always be full of fuel. Hence, if there is a leak, it will be fuel leaking OUT of the line, not air leaking INTO the line.

    We ended up with the same problem after we starved our engines for fuel...mine was starved due to a plugged fuel filter, your buddy's was due to low fuel. So now we have engines that are acting like they have air in the fuel system. We have taken measures to prevent new air from entering the fuel system.

    Is it possible that we have simply not purged the existing air from our fuel systems?

    Is there some sort of plug or valve that we need to crack to allow the air to escape our fuel pumps?

    Is there a particular fuel line that is plugged such that air cannot escape? One response to my thread was that a bleed line from the fuel pump may be plugged. I cracked the fitting from that line while the engine was running and fuel escaped. Perhaps we need to find the highest point in that line and crack the line there. On my truck the bleed line from the pump joins the return line from the back of the rear cylinder head in a Tee fitting, and from there goes back to my fuel tank.

    Plugged fuel return?

    I'm just thinking "out loud" hear. Anyone can feel free to chime in. Thanks for all the help, guys.

    Cheers,
    Phil
     
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