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No gas to carb.

Discussion in 'Early CJ5 and CJ6 Tech' started by mdmeltdown, Feb 13, 2011.

  1. mdmeltdown

    mdmeltdown Member

    I've been driving the jeep and when I went to crank it up this weekend, it ran for about a minute and then died. I cranked it up probably 2 or 3 more times where it would run for about 3 seconds and then die. On the fourth time, it wouldn't crank at all. So....or course, I found out it wasn't getting fuel to the carb anymore.

    Been trying to figure it out. I think I've got it narrowed down to either the fuel pump or filter.

    Just some background on this...225 V6; It has OE fuel line routing and the steel lines were all cleaned previously. Its got a new fuel pump, fuel lines (the rubber hoses and plastic ones), sending unit, and brand new poly tank; none of the lines are pinched; It has a full tank of gas

    I found out I put the fuel filter on backwards. I blew on the filter the correct flow direction and I did notice some resistance, but I can't really tell if I was just blowing out what gas was in it. First question is, will running the flow backwards stop up an inline filter?

    Second part: I took off the lines between the pump and the carb. Now I can see the rubber line sticking up that curls out of the pump that goes to carb. I cranked on it for 20 or 30 seconds to see if the pump was still working. It didn't squirt very much, but I did notice the end of the line was wet with a little gas.

    Second question: Is my pump working the way it is supposed to with just the cranking RPM's? Should it still squirt quite enough to notice gas everywhere?
     
  2. Bobatwarsaw

    Bobatwarsaw New Member

    New fuel pump and blow out the lines
     
  3. mainejeep

    mainejeep Member

    do you happen to have a fuel filter before the pump by chance?
    how much gas is in the tank? only asking because my pick up tube is short on my sending unit so when mine runs low it wont pick up fuel.. hope this helps
     
  4. Patrick

    Patrick Super Moderator Staff Member

    Sounds to me like a bad pump. The filter should flow backwards.
     
  5. mdmeltdown

    mdmeltdown Member

    It's all a stock setup. The filter is after the pump.

    I bought a brand new pump when I rebuild the engine however long ago. Is it pretty common to get a get a new pump that goes bad right after it gets used?

    If it is bad, I wonder if that is causing another problem I was having. I've been all through all the systems because I have a miss. The timing is correct, and the carb was looked at again by the carb guy that rebuilt it the first time. I've got the mix screws set pretty well. It DID fire over with one touch of the key before this fuel issue. It has a slight miss on idle and really misses on accellaration. I took the carb back to the carb shop because i was told the accelarator pump could cause that and everything was fine. I even bought new plug wires and new spark plugs. Could inconsistant fuel delivery cause a miss on accelaration?
     
  6. Patrick

    Patrick Super Moderator Staff Member

    No, not really. Not a sharp miss, which is usually an ignition issue.
     
  7. mdmeltdown

    mdmeltdown Member

    Ok, here's a question for when I put it back on. When I bolt up the pump, do you just shove the arm up against the inside and suck it down or is there some kind of order of installation for that?
     
  8. mainejeep

    mainejeep Member

    mine had directions that said tilt the arm downward and slide in place then bolt up. this would help in making shur the lobe was on top of the arm. IF you can look inside you can make shure that the lobe is at high position and then the arm will be under it. hope this helps
     
  9. Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    The fuel pump should squirt a stream of fuel at least a foot in the air. Mine will shoot it above the top of the engine.
     
  10. unclebill

    unclebill Banned

    i had crap in my tank and it plugged the gas hole inside the tank as well as plugging the filter.
    i put compressed air through the filter to the tank.
    and it ran again.
    so i knew what needed fixing.
     
  11. mdmeltdown

    mdmeltdown Member

    I wouldn't imagine it would get stopped up because the tank is a brand new polly tank. I did make sure the lines were all clean before I put them on....plus I've driven it probaby 40 miles before it stopped up, so that would have to mean if it got stopped up, it came from the tank
     
  12. AKCJ

    AKCJ Active Member

    Before you replace the pump, test it for flow - just put the discharge hose in a jar to see how fast the pump pumps. You can also do a pressure test but I haven't seen a pump that flowed good not have enough pressure. Note that you may have to pour some gas in the float bowl of the carb to do this test.

    Did you already check or replace or remove the sintered filter at the carb inlet?
     
  13. bobo

    bobo Sponsor

    Before got to carried away would un hook the line from the tank(at the fuel pump) and see if gas runs out, this is agravity system and gas should run freely and if not tack uncle bills advice and blow out the line:rofl:
     
  14. pilebuck

    pilebuck Member

    I just went through the same problem i took the fuel line off at the pump the one that feeds the carb and blew air in it after that the fuel ran great.Thanks to all the people here problem solved
     
  15. jeepcj

    jeepcj Member

    sounds like the pump. put a filter on before and after the pump. before it to keep the pump from getting clogged and after to keep carb from getting plugged.
     
  16. jeep2003

    jeep2003 Well-Known Member

    poly tank pulls from the top. You didnt happen to use a cork gasket for the sender? Iv seen those come apart and clog up the line
     
  17. mdmeltdown

    mdmeltdown Member

    Thanks guys. I figured it out. I took out the driver's seat and took out the sending unit with the hoses still attached. I took off the large fuel line that goes into the pump. I found some rubber hose and jammed it up inside the line and put the other end in a cup. I then blew out the line from the intake pipe on the sending unit. I figured I might as well blow on as much of the line as I could incase a clog was in one of the shorter connections. Nothing looked or acted clogged. I then crawled under the jeep and took off the vacuum line at the bottom of the pump. Gas went everywhere. Then I saw it...........(suspense)..........."A HOOK hanging from the rearview mirror!!!" (just kidding, I hope someone caught that movie reference). Anyway; the metal vacuum nipple on the pump looked like the end of an airbrush gun. There was like a thin piece of something sticking out of the tiny hole. I pulled it out and it was some kind of curled up paper thin piece of plastic. I cleaned all that up, blew out that line and put it all back together. I took a plastic cup, filled it with gas, and wrapped a paper towell around the unconnected fuel line connection that goes on the carb. I cranked on it and it sucked all the gas out of the cup real quick. The paper towel on the other end was soaked.


    Here's my question to you guys. Apparently when I filled up the gas tank, it made the fuel level even with the inlet on the vacuum line port on the sending unit and it sucked up some plastic shreds floating on top of the gas. Is that vacuum line supposed to suck gas? If so, have any of you put an inline filter on that too?
     
  18. Patrick

    Patrick Super Moderator Staff Member

    I'm confused about a vacuum line on the pump..And the sending unit?
     
  19. mdmeltdown

    mdmeltdown Member

    OK, are there 2 sending lines?
     
  20. djbutler

    djbutler Sponsor

    One is a return line...helps to prevent vapor lock by keeping continuous circulation of fuel through the pump.

    Don