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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

    That is very possible actually.

    These fuel tanks are a very weird shape, they have an indentation kinda like a horseshoe. Both pickups go under the space between the bottom of the tank and the "horseshoe"spare tire indent in the tank . That is why I thought maybe the pick up was not below the fuel level even though the tank is about half full. Forcing it down broke it off, that's when I switched to the other pickup. Now I had to siphon it to get the fuel to start flowing to the pump but even after driving it with aux tank it still is flowing if i tank clamp off rubber line. The weird thing is that as soon as soon as that tank is hooked up the flow slows to a dribble to filter and carb. While hooked to that fuel tank take the carb out of the equation and fuel seemingly flows as it should. Hook to carb and aux tank it flows as it should. So something weird inside of tank that I can't see.
     

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  2. Ron Emerson
    Joined: Feb 1, 2017
    Posts: 198

    Ron Emerson

    So I have a question ,do you have the tank back out. 1)Have you looked to see if something is floating around in the tank. 2) did you do a visual with the sending /pick up along side of the tank to see if the pickup goes to the bottom and is it the correct sending/pick up unit.3) is there a filter on the end of the pick up tube. Can you show a picture of the real tank on your car. I have seen packing slips and other things floating in and around in side fuel tanks. My suggestion would be remove the tank and take a very good look inside. I had a 1963 Chevy that did the same thing and the filter on the pick up tube was sucking shut with debris .
    Good luck
    Ron.
     
    Desoto291Hemi likes this.
  3. The fuel tank does seem to be 'the most likely suspect'. Is it possible to contact the maker to get them in the loop? They are apt to know exactly what's going on. I don't have many details about what the tank is made for, where the nipples or fittings are located or why you're choosing to use this particular tank. So I'm mostly guessing in the dark.
    I think, if I was in your circumstances, I would probably weld in my own bung where I believe it would do the job best.
     
    rfraze likes this.
  4. sevenhills1952
    Joined: Mar 14, 2018
    Posts: 956

    sevenhills1952

    I wouldn't want to weld on a tank that's had gas in it.

    Sent from my SM-S320VL using Tapatalk
     
    rfraze likes this.
  5. 2 for you.
    First is Related but not on topic.
    Back a few years - brand new Harley would just die when ever the hell it wanted for no good reason. Repeatedly over and over leaving the guy stranded and getting towed back to the dealer only to start and run like any new vehicle should. Frustrating for the first few time and infinity infuriating after several.
    That’s the presentation issue and I’ll just skip the ensuing drama that involves screaming matches pissing contests threats, lawyers and the distraction.
    Here’s the cause.
    Guy takes delivery of the bike in the winter. He takes the Sheetmetal off and has some custom paint work done, gets some chromie dodads and spends a bunch of money. Once the dealer exhausted every and all available resources trying to find the problem it was discovered , a rag left by the painter in the tank.

    2
    Brand new engine, installed in a 62 nova, overheats in a few mins run time. Engine builder and shop owner start a pissing match.
    Engine builder ran it for quite some time without any issues, the engine was delivered and sat in the corner for a few weeks. It was installed and overheated. Two brilliant minds caught up in a pissing match couldn’t find time to diagnose the issue.
    Again skipping the drama.
    Comes here and somehow I’m supposed to fix it. I spoke with the builder, and the shop owner. First thing I find is no water circulation. Second thing I find Is the radiator drained completely fine but the intake manifold did not. Third thing I found was the lower radiator hose installed over the shipping cap on the waterpump. This car sat for 6 month while they argued when less than 30 mins of clear headed thinking figured it out.
     
  6. Then you should not do it. Leave it for professionals. I feel the same about neuroscience and brain surgery.
     
  7. It’s absolutely 100% impossible to diagnose an obscure ( yours is obscured) fuel delivery problem without a fuel pressure gauge. It is possible to stumble blindly into the problem and correct it. Figuratively you’re walking around in the dark and hopefully will trip on the problem. Also likely to trip over a bunch of other things as well.
     
  8. brajaboy
    Joined: Aug 25, 2011
    Posts: 46

    brajaboy
    Member

    This is what I was thinking actually. There already is a drain bung on the bottom of the tank. I could easily adapt a fitting to screw the feed tube running to the pump. Or, weld one much lower than it See pic, its almost half way up the tank) so it will always be getting fuel and draining without having to suck or siphon. maybe how high and how long the pick up tube is is the problem? Maybe its to high or pickup to long for the pumps to be able to pull /push the fuel up to the carb. Whereas when its siphoned from the jerry can it has a constant supply and it only has to push it. Very possible no?
     
  9. brajaboy
    Joined: Aug 25, 2011
    Posts: 46

    brajaboy
    Member

    While this may be possible it is unlikely as once pressure is released by taking carb out of equation then it runs as should. I am gonna take out on the hwy now to see what happens, will update.
     
  10. brajaboy
    Joined: Aug 25, 2011
    Posts: 46

    brajaboy
    Member

    Well, had a couple of hickups on the hwy but overall it worked as it should with the jerry can. I was pushing it though like 70 miles + an hr when it should really only be cruising at 65 and that was up hill in parts too so couple of hickups could be timing or carb set up. So very interesting but... I will drop the tank tomorrow or at least drain and see if adapting the drain plug makes a difference.
     
    31Vicky with a hemi likes this.
  11. Taking the carb out of the fuel delivery equation by disconnecting it actually is removing a restriction. That restriction is the small orifice of the needle valve. Without restriction the pump moves fluid. Guessing at the pumps ability to build pressure isn’t good. Testing the pumps pressure is what’s going to help.
    Now yet with A remote can and the car runs as it should so that eliminates the carb. It’s functional and operating as it should. This leads to a conclusion that the pump might be making enough pressure as long as it’s on a remote tank.

    Those points made lead to suspects of whatever , anything and everything that is different between running the remote tank and the cars fuel tank. Any line, clamp, fitting, senders, pick up tubes literally everything different. Now if all you did was take the line off the sender and drop it in a gas can ( is that what you did?) then that’s where to look for an issue.

    Back in post #9 (you might want to re read that) I said it sounds like the pump is sucking air. Maybe I’m correct maybe I’m not but it still sounds that way.
    Here’s the PITA in this woodpile. “There’s a release of pressure when I take the line off,,,” might be a red herring statement but unless the float is remaining up with the bowl empty there’s NOTHING to build pressure against. Switching to a remote tank will not make anything different with the carb. What is it? Why is it? Is this the problem? Is it a natural phenomenon and just a symptom of the problem. Maybe it’s just confirmation bias of nothing
     
    Desoto291Hemi likes this.
  12. rfraze
    Joined: May 23, 2012
    Posts: 2,008

    rfraze
    Member

    Until you get fuel flowing out of the tank (without something stopping it) it is likely problem will continue.
     
    Desoto291Hemi likes this.
  13. B.A.KING
    Joined: Apr 6, 2005
    Posts: 4,039

    B.A.KING
    Member

    I have posted this story before so i'll cut to chase. Friend had a car, run for a while shut off. Found dead mouse in tank. suck it to pick up,die, let set 15 min ,run, die, same thing.If you haven't already, change ALL your rubber lines also. Keep us posted.
     
    Desoto291Hemi likes this.
  14. rfraze
    Joined: May 23, 2012
    Posts: 2,008

    rfraze
    Member

    Customer truck. Been in a couple of shops. Electric fuel pump had been put between the stock pump and carb, with wire to coil Hot. Ran until you drove it a while. Die.
    Fuel would run out of tank outlet. I moved electric pump close to tank outlet and added a fused circuit with switch. It ran good until it died. I found a thin plastic matt (like sink drain cover) in tank that eventually moved over to cover outlet hole. (Maybe it was covering filler neck, before it fell into the tank.) Truck still runs years later.
    Follow the process. Eliminate the problem.
     
  15. The Ford glass bowl carbs are not a good design, I replaced mine with a 52 Chevy 1 barrel carb and gained performance and reliability, my 52 Ford went 72 mph at the drags with that Chevy 1 barrel carb on my Ford.
     

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