HELP!!!Priming my fuel system!

Discussion in 'Trucks [ Eighteen Wheelers ]' started by local-trucker-dude732, Feb 14, 2009.

  1. local-trucker-dude732

    local-trucker-dude732 Bobtail Member

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    I recently ran my 94' fld 120 low on fuel, enough to get some air in the system, but not completely dry, now at idle the motor bogs down every now and then, like i have an air pocket in the fuel system somewhere? i filled the fuel filter through the cap on the top of it but still have bogging problems often at idle, even after driving it for a while, i know i have to prime the fuel system but i'm new at this and need to know the complete procedure if anyone could please help!!!! Thank for your time!!!!!
    p.s.- its a 94' Freightliner FLD 120 with a cummins M11, Thanks Again:biggrin_25525:
     
  2. PaulE

    PaulE Medium Load Member

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    you say you filled filter thru cap on top. is this a Davco ? big black ring at bottom of glass. black cap on top? can see filter cartridge ?
     
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  3. Heavyd

    Heavyd Road Train Member

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    Yah, sounds like a Davco. Make sure the o-ring is still on the top cap.
     
  4. PaulE

    PaulE Medium Load Member

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    ill assume its a Davco, if you did not disturb the large ring at bottom then take top cap off.remove o ring from cap carefully...clean o ring,underside of cap and top of glass where o ring seals with diesel fuel . put o ring back on cap .use your finger to dab fuel on o ring and sealing area on top of glass. both should be wet . screw cap back on just till o ring contacts glass. then 1/2 to 3/4 turn more. should just be snug.

    will be away from site rest of day so if that dosent work someone will help you. good luck
     
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  5. local-trucker-dude732

    local-trucker-dude732 Bobtail Member

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    not the glass type, its the metal one like an oil filter, should i prime the whole fuel system? and if so what would the procedure be???
     
  6. ampm wayne

    ampm wayne Heavy Load Member

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    My experience with air in the fuel system is that once you get it running and can keep it running it will be fine. I wonder if you need to replace the fuel filter. You may have sucked dirt into the filter from running low on fuel. Also,do you have a water seperator? If I was you I would change both filters and see if that helps. If not you may have an injector problem. Also,run some fuel conditioner in your next tank of fuel.
     
  7. kentuckyrambler2

    kentuckyrambler2 Light Load Member

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    local-trucker-dude732:

    It sound like you picked up trash from fuel tank, and it has affected your injectors.

    This is what I would do.

    (1) replace the fuel filter
    (2) fill new fuel filter with automatic transmission fluid before installing it. ( ATF, or dextron 3 )

    The automatic transmission fluid will clean the injectors and works better then fuel treatment or injector cleaner.
     
  8. PaulE

    PaulE Medium Load Member

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    you guys are thinking too hard. the only thing that happened was he ran low on fuel.your diagnosing too far ahead. secondary filter is not full of fuel. fill filter as full as possible . theres air in secondary filter . primary will not be full unless its gelled or its at capacity to hold dirt...get air out before going further