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No gas getting to carb.

Discussion in '1965-1970 Shelby Mustang GT350 & GT500' started by GCRIV, Jul 15, 2008.

  1. s2ms

    s2ms Well-Known Member

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    Re: Fuel pump working or not?

    You mentioned in your other thread on this subject the eccentiric had come loose and you tightened it up. Any ideas why it came loose? Could it have come loose again?
     
  2. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    I don't think the eccentric has come loose again. It seems to run fine most of the time. It just cut out on me the other day. When I push the rpms up, I can see the gas streaming into the fuel filter, it just doesn't seem like it's enough. I think at high rpms like when I was driving down the highway, it just can't keep up with the demand, and gets starved. I was asking someone else, and it looks like there is something, maybe some kind of filter at the fuel inlet on my Carter carb. I wonder if I've got some kind of blockage there, or at the pickup in my tank. It figures, I just took the car to the gas station on Saturday for it's big maiden voyage. I filled the tank to the brim. Now I've got to try and siphen the gas down far enough to get the tank out of the car :-( I didn't have time to get into the carb and see if that inlet has some kind of fuel filter.

    p.s. can't figure out why in the world that eccentric was a problem. When I tried to tighten it back down, it's as if some of that pin on the cam was sheared off. I never have found the other piece of the pin. Puzzled as to how, or why that could have ever had enough pressure to shear that pin. After all, it's only the pressure of the mechanical pump. Wonder if maybe the pump got jammed or something.
     
  3. tommyleea

    tommyleea Well-Known Member

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    Re: Fuel pump working or not?

    This is getting confusing. You say it isn't getting fuel from the gas can, but you don't know if there is a filter at carb. I think you need to go back to square one. Some of the eccentrics don't have a pin, you just torque it down. When did it stop working? Did you change the timing chain? Again, usually the mechanical pump won't be intermittent. I am confused now.
     
  4. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    O.K. let me try again. I discovered the eccentric was loose. I took the timing cover off, and the pin in the cam had been sheered off somehow. I replaced the pin, and torqued it down. I put a new fuel pump on with an inline clear filter. After believing there to be a blockage in the tank, or the line coming from the tank, I disconnected that line and put it in a can of gas. It isn't getting any gas out of the can, and up to the carb. However, when connected to the line from the tank, it will pull just enough to keep it running, so I know the pump is working, just not pumping enough, indicating some kind of blockage. Thats why sunk the intake line into a can of gas.
     
  5. Doug_GT350

    Doug_GT350 Well-Known Member

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    Re: Fuel pump working or not?

    Again if it's pulling some fuel from the tank, and none from the can on the floor, I don't think the problem is in the tank. I'm not sure of the Carter Carbs but if there is a small cylindrical piece (like a roll of nickels) at the inlet to the carb that would be a filter. Check at an auto parts store for a replacement first then you know what it will look like. It could be a sintered brass filter inside the carb at the inlet also. What about a pinched or cracked fuel line from the tank to the fuel pump. It might be small enough that it wouldn't leak fuel but you could be sucking air. Buy a long piece of fuel line, long enough to go from the tank to the fuel pump and by-pass everything just to see if it will run that way. It may help narrow down the problem. Borrow an electric fuel pump and temporarly by-pass the mechanical one. Try to keep it simple don't start tearing down until you isolate an area.
    Good Luck, keep us informed.
     
  6. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    Well, I understand what your saying about bipassing the line from the tank, but that's what I'm trying to do by just putting the intake line into a can of gas. But I'm not getting any flow that way. I have something round at the inlet of my carb. I can't see what it is, it's all in the housing of the carb, but there is some kind of round protrusion. I'll see if I can screw it out of there tonight. I blew the line clear that runs from the pump up to the carb, and there wasn't anything in it. So I'm pressed to find out why it won't suck it up out of the can on the ground.
     
  7. Doug_GT350

    Doug_GT350 Well-Known Member

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    Re: Fuel pump working or not?

    Okay, I was thinking the can of gas was in the rear of the car by the tank, Sorry
     
  8. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    Well, I just checked, and there is no other filter than the clear in-line filter I installed. Once again, I took the line loose that feeds the carb. It is chugging gas out of there, and it appears that it is letting adequate fuel into the filter. I wanted to make sure the eccentric hadn't come loose again...it appears that the pump is working properly. One thing I just can't figure, and I'd be happy if anyone could tell me....why won't it suck gas out of a can sitting on the ground? Everyone I talk to tells me it should. But there is no blockage in the line from the pump to the carb.
     
  9. tommyleea

    tommyleea Well-Known Member

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    Re: Fuel pump working or not?

    Prior to changing out my tank because of rust out, I ran my car on a small gas can secured next to the radiator. Didn't take any trips with it, but drove it around the yard. If you disconnect the line at the carb, and crank the motor over, you should get a strong shot of gas at each stroke of the pump. If not you have a bad pump, or the pump is not operating for some reason. If you get gas at the outlet, then you have a problem at the carb. Maybe junk in the needle and seat, or maybe float stuck/jammed. This is using the external tank procedure to eliminate a fuel tank problem.
     
  10. Mike Christie

    Mike Christie Well-Known Member

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    Re: Fuel pump working or not?

    "inline clear filter that you installed" keeps being mentioned.
    Is it possible that the filter was installed backwards? Is it a directional filter.
    I think I did this once and I had fuel feed problems.
    How big is the clear filter you installed? Larger plastic one or the smaller glass with metal ends?
    How about bypassing the newly installed filter and see what happens.
    Also, take reading with a fuel pump pressure gauge and see how many pounds of pressure
    the pump is putting out.
    Look closely at the newly installed filter and make sure its installed correctly.
    I hope it's something simple.
    Mike
     
  11. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    Well, I don't know where else to turn. I haven't eliminated the in-line filter completely. The filter has 2 different size openings. You trim the inlet, and outlet to allow a bigger diameter of fuel to flow through. I have opened it up as much as it will go. It's a good 3/8" open. Should be more than adequate for fuel to flow through. I ran it, and it is STILL not getting adequate flow. I am out of ideas. When I disconnect the line feeding the carb, and turn the car over, it pumps ample fuel. It also lets ample amount of fuel into the filter. It's when I connect the line to the carb that it will only allow so much to get through. I really don't think it is a problem inside the carb with a needle or seat. I think if that was the case, it would either flood, or not start. Neither is the case here. I'd love to hear any other ideas you might have.

    I've tried turning the filter both ways. According to the arrows on the filter, I've got it running the right way. I appreciate the tip though.
     
  12. BillH

    BillH Well-Known Member

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    Re: Fuel pump working or not?

    IF you have checked the lines for air leaks, and are sure that there is no restriction in the sending unit/fuel pickup in the tank, then I would take a long hard look at the fuel pump.

    Your original post said you just replaced the fuel pump. Where did you get it? Is it a new pump? One more item to think about; The big block pumps, (332 thru 428) look identical and are almost impossible to tell apart. The only difference is the arms are in a sligitly different place. The FE pump, when installed on a small block will not be cycled to full stroke and pump very little, if any gas. In the years I worked in the auto parts business, I saw fuel pumps mis-packaged more than once.
    Good Luck
     
  13. Mike Christie

    Mike Christie Well-Known Member

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    Re: Fuel pump working or not?


    Ok, now I'm really suspicious of the new fuel filter. This filter reminds me of the tube of caulk I've been winterizing with. Clip off the nipple until the right amount comes out. ..but yet, still...test the outlet side of the fuel pump with a simple vacuum/fuel pump gauge. The reading should be close to what the manual indicates. If the reading is constant (other than minor pulsing), then look upstream, from the fuel pump outlet to the carb. I'm not sure what carb you have, I remember many had a porous brass(?) cylindrical shaped little fuel filter in the carb inlet. Check closer on that if your not totally convinced it is clear. Also, get a vacuum reading on the engine while it's running could be helpful.
    If all the vacuum/fuel pump readings are within limits and assuming engine tune is ok, then carb. Needle/valve, accel. pump, floats. Power valve, manifold gaskets. Ummmmm........
     
  14. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    Well, after I installed the new pump, and all of this happened, I took it off again, and checked the arms thinking maybe the new pump had a different, if not shorter arm. They were identical.
     
  15. tommyleea

    tommyleea Well-Known Member

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    Re: Fuel pump working or not?

    OK; let's start over. Your first thread stated that you just replaced the fuel pump on your 289 engine. I know this is getting old, but we need to back track. I just replaced the fuel pump on my 289 because.......? fill in the blanks.
     
  16. s2ms

    s2ms Well-Known Member

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    Re: Fuel pump working or not?

    This seems to indicate some problem in the carb to me. I've had brand new carbs not run worth a darn due to some small restriction in a tiny passage. I would try another carb.
     
  17. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    Well, first.....I replaced the fuel pump because I thought it was bad. When I first started describing my symptoms to a friend, he said it sounded like a weak pump. That's why I put a new one on.

    As for the carb, I think that will be my next focus. I'm a little afraid of tearing into it, I've never tried rebuilding a carb. Don't exactly have the money to buy a new one yet. Well, I don't even know how much they are. Might ought to check.
     
  18. Doug_GT350

    Doug_GT350 Well-Known Member

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    Re: Fuel pump working or not?

    How long was the car sitting before it's "maiden voyage"???? I'm going to go with the carb being all gummed up! You've eliminated everything else! Was the carb on the car all along or was it purchased from someome else and bolted on???
     
  19. GCRIV

    GCRIV Well-Known Member

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    Re: Fuel pump working or not?

    The carb has been on the car all along. It's probably 15-20 years old. I went home and tinkered with it a little at lunch. I have a plug that restricts a vacuum at the front of the carb. Never noticed before, but it is cracked pretty bad. I can see daylight through the crack. I also have a bad leak of some kind at the front left of the carb. Kind of close to the electric choke. I wouldn't mind buying a new carb, I just wish I knew that would fix it. I've spent dollar after dollar chasing this problem. I thought $50 for a new fuel pump was bad, I cringe to think what a carb would run.

    It recently has started idling very very high once it gets warmed up. Doesn't that also point twords some kind of vacuum leak?
     
  20. Doug_GT350

    Doug_GT350 Well-Known Member

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    Re: Fuel pump working or not?

    Once you get it running and the idle is steady, spray around the carb with some carb cleaner, if the idle changes while you're spaying that would indicate a vacuum leak. The spray temporarily seals the leak.
     

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