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Not getting fuel to 350

Discussion in 'Chevy Trucks' started by Daveintw, Feb 2, 2003.

  1. Daveintw

    Daveintw Junior Member
    from Texas
    Messages: 1

    I have had the fuel tank cleaned and repaired, replaced the fuel line, replaced the fuel pump, added a fuel pressure guage, replaced the fuel filter in-line and in the Carburetor, and rebuilt the carburetor. Started up the truck and was getting 5.5 to 6 lbs. of pressure and good fuel flow. I drove it for 4 blocks and checked it. I was getting spurts of fuel, from 4 to 5.5 lbs. of pressure. When at the lower end of pressure the fuel would flow just a little better but still in spurts.

    I am totally confused and have no idea what it is that I am missing. Help please.
  2. snowflake

    snowflake Member
    Messages: 86

    if motor has a lot of miles on it the cam lobe for the fuel pump mite be worned down where it aint pumpin all the time, or you got a defective fuel pump butt sounds more like its a junk pump

    just my 2 cents got change
  3. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    Just for kicks, remove the fuel cap, let it run, and check the pressure then. If the pressure improves, then there is a blocakge in the line to the charcoal cannister under the hood where the tank vents to. IF the truck is a non-catalyst, then there is a line right off the tank with a cap on it for the vent, which may be damaged.

    (If the vent is plugged, a vacuum will form in the tank, making it harder for the pump to get fuel).

    If there is no improvement, I don't know what to tell you. How many miles are on the motor?

  4. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    snowflake was reading my mind on the high mileage wear.

  5. snowflake

    snowflake Member
    Messages: 86

    never thought of that fuel cap mite be plugged or not a vented one had that happin to me alllready runs good at first than quiicts looosed fuel cap annd about got sucked into tank from alll the vaccum in tank.

    just more two cents where.s my change lol
  6. wyldman

    wyldman Member
    Messages: 3,265

    If your getting 4 psi min for fuel pressure,then it's not a pressure problem.On a carburated vehicle you don't really need much pressure to keep it running.If the pressure is low,then it may run out of fuel on long acceleration runs,but other wise it should run half decent.Have you got the fuel lines connected correctly ?

    I would tend to say more a needle and seat problem,or float level.

    What kind of carb is it ? Where are you taking your pressure readings and where are you looking for these "spurts" of fuel ?

    SCFALL Member
    Messages: 47

    You need to check for volume also not just pressure. Take the line off at the carb stick it in a glass jar have some on crank it over and see how it pumps. I have had some with good pressure 6.5 to 7 lbs but would not give any flow. I f you find a low flow change the pump again and try if that doesnt do it blow the line backward. also is vapor lock a posibilty new lines to close to manifold or maybe top rad hose hope it helps Scott
    Last edited: Feb 2, 2003
  8. paul soccodato

    paul soccodato Senior Member
    Messages: 430

    how did all this come about?
    does the engine run ok?
  9. Dan S.

    Dan S. Member
    Messages: 31

    Does your truck have a strainer on the fuel pick-up in the tank? I had the same symptoms on a truck I used to have, it would go about 3/4 of a mile and run out of gas, let it set for about 30 minutes and it would start up and go another 3/4 of mile and quit again. Turned out to be that strainer was clogged, Good Luck
  10. 68bullit

    68bullit Member
    Messages: 36

    one thing that happens in older trucks is the fuel pump pushrod gets wore out and the pump doesnt receive the proper amount of stroke.

    it will work fine at idle or lower speeds but will stumble at higher rpms.

    another way to tell is usually the will be a TICKING sound around the fuel pump area.good luck