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Customs Weird fuel delivery problem??

Discussion in 'The Hokey Ass Message Board' started by brajaboy, Mar 9, 2020.

  1. brajaboy
    Joined: Aug 25, 2011
    Posts: 46

    brajaboy
    Member

    Having a weird fuel delivery problem. 1959 Ford wagon with a stock to 223 and 1 barrel carb. This happened Before & After replacing these parts. Carb, fuel pump from mechanical to electronic, fuel filter, blowing out the line at carb to the tank with gas cap off.

    Here is what it's doing. When hooked up to the carb it will fill the fuel filter and the bowl but once it is started it will drain both without replacing. I can see it because both filter and bowl are see through. When I unhook from the carburetor it is like there is an air pressure release and the fuel begins to flow freely and as normal. Hook it backup to the carb and it will fill the bowl and the fuel filter until it is started then it starts the process all over again until unhooked from the carb. It does this whether it is hot or cold so while I could possibly be vapor lock it would be weird when it was cold that it would do that no? again it is did it Before & After replacing the parts above to try to fix problem and with gas cap on or off. Any ideas what it could possibly be?
     
  2. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

    Could be a bad rubber line. Either partially plugged, limiting the flow, or cracked so that the pump is sucking air through the lines.



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  3. brajaboy
    Joined: Aug 25, 2011
    Posts: 46

    brajaboy
    Member

    Ok I replaced all rubber lines when I changed to elec fuel pump. But maybe they are not tight? But I did it before. I will blow out line again just to be sure there is nothing clogging it.
     
  4. hotrodjack33
    Joined: Aug 19, 2019
    Posts: 4,128

    hotrodjack33
    ALLIANCE MEMBER

    Check the rubber hose coming off gas tank. Posted this below a couple weeks ago.

    Years ago I stuffed a 425 dual quad Buick engine into a 48 Ford Pickup. I could drive it about 3 miles and the carbs would be dry. Let it sit 5 minutes, pump the hell out of it and it would drive 3 more miles and die...would do that all day long. Figured the mechanical fuel pump couldn't keep up with the carbs, so I added an inline electric pump. That made it worse...could only drive 1 mile at a time before it would die. :(
    It ended up being the 8 inch long rubber hose from the gas tank to the fuel line. With the mechanical fuel pump, it would suck closed after about 3 miles. Adding the electric pump just made it suck closed faster.
     
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  5. jaracer
    Joined: Oct 4, 2008
    Posts: 2,419

    jaracer
    Member

    It's either a bad rubber line as others have mentioned, or something in the tank that covers the inlet. When you crack the line it falls back and allows the line to fill. Have you ever had the tank off?
     
  6. clem
    Joined: Dec 20, 2006
    Posts: 4,188

    clem
    Member

    Did you remove and clean fuel tank ?
    Blowing out the line just pushes any rust, broken down gas cap gasket material etc, back into the tank to be sucked back into the fuel line when you start up again ..............
     
  7. loudbang
    Joined: Jul 23, 2013
    Posts: 40,276

    loudbang
    Member

    Try running it with the gas cap off. Cheap (free) to try and no parts to buy. :)
     
  8. spanners
    Joined: Feb 24, 2009
    Posts: 2,073

    spanners
    Member

    Use the old process of elimination technique. Disconnect the fuel line between tank and pump and connect a small container of fuel to the pump. Fire it up and if it works fine, it's between the pump and tank.
     
  9. it sure sounds like the pump is sucking air, like a hole in in your soda straw. Rubber lines can suck air but not leak fuel.

    Are you saying the needle and seat valve are holding air pressure with a dry fuel bowl? That’s a different problem
     
  10. ^^^” When I unhook from the carburetor it is like there is an air pressure release and the fuel begins to flow freely and as normal. Hook it backup to the carb and it will fill the bowl and the fuel filter until it is started then it starts the process all over again until unhooked from the carb“
    Freely out the line again where it connects to the carb? Sounds like the needle and seat is blocking the flow somehow by that statement.
     
  11. GordonC
    Joined: Mar 6, 2006
    Posts: 3,141

    GordonC
    ALLIANCE MEMBER

    What type of fuel pump do you have? I had one that said to mount it below the tank tilted at somewhat of an angle. Thought it was weird but did as suggested. Sounds like the pump is running dry either from a leak in the line or a blockage in the tank.
     
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  12. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    As was stated, take the cap off and try it. Maybe the tank vent is plugged. Lippy
     
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  13. I’ve said it before and it still stands true.
    I’ve wanted to be more wrong than now but I wasn’t then and aren’t now- people don’t read much past the 7th word
     
  14. Even when they say it twice
     
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  15. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 956

    sevenhills1952

    Why not pressure and volume test?
    Disconnect line going to carb. Hold a clear jar while helper cranks 20 seconds. Should have (from memory) about 6 ounces gas. Be sure it's clean.
    Then most vacuum gauges also check low pressure. Clamp it to line again crank 20 seconds. Should have 4-5 psi pressure. See if it holds pressure (no leak down).

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  16. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member

    I am leaning towards the cracked rubber line at the tank ot in tank filter clogging up.

    If it was doing the exact same thing before and after replacing those parts it pretty much has to be.

    Btw.... Did you try it with the gas cap off?..... Just kidding!!!!
     
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  17. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member


    He has an electric pump. No need to crank the engine. Just has to energize the pump.
     
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  18. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 956

    sevenhills1952

    Did he try has cap off though

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  19. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    Did he take the cap off yet? :D
     
  20. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    It's not my reading, it's my memory. :)
     
  21. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

    I thought that too, but he says he replaced the carb. Seemed the odds of having the needle or float stuck closed on two carbs was pretty low. Plus, the pump will fill the carb bowl *and* fuel filter when the engine is not running, then the engine sucks the carb and filter empty when started, so at least some fuel is flowing through the needle and seat.



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  22. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 956

    sevenhills1952

    If original fuel tank it probably has a gallon or two crud in it.
    When I replaced tank in wife's '55 Chevy it had enough garbage to fill a bucket. The sending unit was all but eaten away. I replaced steel line and hoses all the way.
    I don't see how it ran at all. Now it runs like when her Mom bought it new.

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  23. brajaboy
    Joined: Aug 25, 2011
    Posts: 46

    brajaboy
    Member

    Sorry did not reply sooner but I own a pizza shop here in vegas and it takes allot of my garage time away! So... the tank is brand new so no crud in it that I can see. It is a steel line coming right off tank to brand new fuel type rubber line. The fuel pump is mounted below the tank level so it gets gravity fed. First carb was the wrong carb for the car. It was a weber 32/36 with the load o matic dist. Kinda worked but not really and too tall anyway could not fit a air cleaner. Current one is an original holley 1904. Runs good till runs out of fuel
    All rubber lines have been replaced with new actual fuel lines as I was thinking that was the problem too. But nope still does it. I will take the tank out of the equation to see as someone suggested. There is no vent tube on this tank which is weird. It came with car and is brand new shiny both outside and inside with no crap in it that I can see but maybe some sneaky sob in there f'n stuff up that I cant see so eliminating the tank will tell me that I hope. Will let you know my findings.
     
  24. brajaboy
    Joined: Aug 25, 2011
    Posts: 46

    brajaboy
    Member

    Ok here is what I figured out so far. Take feed line of tank and there is no fuel that comes out of tank which I thought was weird but maybe that's normal? it is just under half way up the tank but pickup tube does go below gas level. But with feed line disconnected from the pump and I blow compressed air into the fuel tank from filler, fuel will start to flow freely that now feeds the pump. At this point just idling or just key on it fills the fuel bowl as it should and fuel filter about half full. But its a slight trickle only not a normal flow rate but keeps it about half full still at idle. When driving it its a different story though. It drains the fuel filter and the we are still at a very slight trickle but not enought to fill the filter or bowl fully and car stars to stumble. But once I disconnect from the carb there is a decent pressure relief and fuel then flows perfectly?? I have replaced all rubber and metal lines in the system but still doing same thing! There is a fair amount of pressure and flow when I take off line to carb. I have a brand new mechanical fuel pump that I tried and the exact same thing happens with it. no fuel until I disconnect from carb then releases pressure and flows perfectly. Took out sending unit to see and inside tank and is clean as a whistle (as its also new) and tried the other fuel pickup outlet (tank has two) repeating all steps above just in case but same thing?? Have between about 1/4 and a 1/2 a tank of gas so its not empty. I do not have another container that I could get high enough and hook up to pump because elec pump is not self priming so have not tried that yet. The wierd thing is unless its hooked up to carb its flows perfectly. Any other ideas?
     
  25. something is stopping the float from dropping.
     
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  26. That’s where you’re telling us this problem is telling you to look now. I know you’ve replaced the carb as well as a slew of other parts.

    Hopefully you’re electric pump Is as far back and as close to the tank as you can get it. The Epumps push fuel much better than they pull.


    The puzzling think is that obviously the problem was there, then you changed parts, and the problems remain. Is it the same problem now? If so none of the parts were the issue to begin with and the root is yet undiscovered and untouched. If the original problem is different then maybe your methods of testing and interpreting are off some how.

    What the fuel pressure on this set up. It would be interesting to see the pressure gauge and the empty fuel bowl while you disconnect the carb. The way you are explaining it there would be pressure (air) and no fuel.
     
    Last edited: Mar 19, 2020
  27. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 2,866

    427 sleeper
    ALLIANCE MEMBER

    Here's my 2 cents worth... (which is usually valued to be considerably less :D) But have you tried running a hose from the carb end of the fuel line into an empty gas can and letting the pump run to see if the fuel flow stops after a certain amount of time? I'm still leaning toward the pick up tube getting blocked after a certain amount of time and sucking the line dry. That pressure release you're hearing probably isn't pressure at all, it's vacuum. If the carb fills up again and fuel doesn't pour out of the bowl vent that means the float is working. I'm sure you've probably checked the tank and pick up a dozen or so times, but sometimes things get overlooked out of frustration. Kind of a "Can't see the forest for the tree's" type of thing.
     
    Last edited: Mar 19, 2020
  28. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

    I keep thinking this too, but he changed the carb out. Two with stuck floats? Possible, but kinda seems unlikely. With the description of symptoms, it has to be at the carb.



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  29. Country Joe
    Joined: Jan 16, 2018
    Posts: 517

    Country Joe
    Member

    Could a rubber line be collapsing?
     
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  30. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,213

    sunbeam
    Member

    I also will go with the carb. It does not take a very big piece of crud to plug the needle and seat. That is about the only reason you would have an air pressure build up . You have air in the line when it is off and when you start the engine pump puts pressure on the line.
     
    Last edited: Mar 19, 2020

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