My recently painted 56 f100 won't work and I believe it is because the fuel does not flow from the rear fuel tank to the carburator. I have a modified 76 nova fuel tank and my fuel pump is apparently working ok. I removed it and tested it outside. I believe there may be a problem with the fuel line. Is there a certain way the fuel line has to be? Does it have to be declining from the tank to the fuel pump? The fuel is just not getting to the carburator and when it does it works ok for 30 minutes or so, it then it quits on me. It'll start for a minute or two after that and then it dies on me. I can't drive the because of it. I've thought about installing an inline electrical fuel pump instead. Do you guys know of any universal electrical fuel pump that can be used together with the mechanical fuel pump, just to help the mechanical fuel pump and have extra fuel pressure? Your comments and suggestions will be greatly appreciated.

Joe
jangel59(No Email Addresses In Posts!)

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How do you know for SURE the gas is not getting into your carburetor? You need to go down and get a fuel pressure tester, put it in the fuel line and find out for sure. It is possible that you have a kink or crimp in a steel fuel line, but it is unusual that the carb isn't drained dry in only a couple of minutes, which would be usual. 30 minutes is not usual, I think. What is waaay more likey, in my opinion, is that your carb is running too lean for some reason (usually gum or varnish or rust from the gas tank, or a combination of all three is clogging one or more of the tiny passageways inside your carb)but when you first start the engine, the automatic choke makes the mixture super rich for a while until the choke element is thoroghly warmed up and the automatic choke comes off "automatically". At this point, either the gum problem in your carb's internals or a vacuum leak somewhere on your engine causes the mixture to be too lean and the engine dies, because it no longer has the artificially super rich choke on condition to compensate for it. Now, if you have a hand choke, that does not apply. But once again, it should happen much faster than that, usually, if you time it, an automatic choke will come off in about 5 minutes by the clock, give or take a minute or two (I haved timed this a number of times).
Also look for possible ignition problems. Honestly, unless the truck has sat unused a long time (months)or you actually find a crimped fuel line, I think if you check your fuel pressure and decide your pump is OK, then I think your problem may be somewhere in your igntion system. There's a carburetor article in the November 2001 issue of "Classic Trucks" magazine about carburetors that gives this useful advice: "Many carburetor maladies have turned out to be bad spark plugs, burned valves or clogged fuel filters so begin by checking everything else first, and we do mean everything. If you have any doubts about the engine's condition, do a compression test or leak down test. Make sure the ignition system is operating properly, air and fuel filters are clean, and the fuel pump is capable of delivering 5 to 7 psi. If all else is in order, then it's time to look at the carburetor."
I quote this to show how, although the problem could be the carb, it is much more likely elsewhere. Elsewhere includes a vacumm leak somewhere on the engine.And that's if your fuel pump tests OK, etc. good luck, and maybe someone else can offer some other helpful suggestions.
-G.B.

 

Do you have a vented cap on the filler neck? I bet the nova originally had a closed fuel system with a charcoal canister. If you plugged the outlet on the tank that this went to, and are using the original non-vented gas cap, it could be getting a vacuum on the tank when the fuel is being drawn out. I wonder if the problem would go away if you left the filler cap off as an experiment?

 

First let me tnank you for your responses. I tried some of the things suggested. I found out that the fuel line was loose by the tank and was actually leaking gas. I fixed that, I also replaced the fuel pump. I know it was bad because I unplugged it from the carburator and then tried to start the engine, no gas came out from the loose fuel supply line. I also cleaned the spark plugs, the engine started for a few minutes after that. I am still having problems. My next step is to check the carburator filter, replace it or remove it just to make sure this is not the problem. I also need to buy a gas pressure gauge to find out the pressure I have. I just think that the gas coming out of the fuel pump may not be enough. Again, I checked this by trying to start the engine with the fuel line disconnected. After I check all this, I may have to turn to the carburator, my guess is that it needs a repair kit.

I wish I knew how to do a leak down test, I know the engine compression is good, the engine is in real good shape. The truck was indeed sitting for a while, the painter took almost five months to paint it. My problem now is that I don't want to take it to a mechanic shop because the truck was just painted and I am afraid they may scratch it. So I got to do as much as I can. I will also be buying a vented gas cap. Thanks again for your help.

On another subject, I took a few pictures of my truck with my digital camera, I tried to post them but was unable to, how can I do that? I thought pasting or copying would do, but it didn't. Please enlight me.

Joe

 

When a vehicle sits around, the fuel gets pretty yucky. After you get it running, you may try some stuff called stabil to keep the gas fresh. If you want to post pictures, you can do it in your gallery. I have only done it a couple of times myself. Go up to the right corner and click on "user gallery" and then click on "manage create" your gallery on the left side of the square chart. Beyond this I barely know myself. I think after you get the picture in your gallery, you can right click on it and go to "properties". Copy and paste the url(long jibberish with jpg at the end) and put this in your post and it will pull it out of your gallery and put it on your post.

 

Coud be your sucking some air between pump and carb.

 

Id be real careful about using Stabil. Depending upon the EPA formulation mandates for your county you could be asking for big trouble by using it.
A good source of local info is the small engine shop as they have to deal with storage issues on a regular basis.

 

Depending on the mods to the Nova tank, is it possible that something is floating around inside the tank and shutting things off. I had some crap come loose after I used a gas additive carb cleaner and it plugged the outlet on my 48, but that was a stock gravity drain feed.

Other than what has been already suggested, any chance it's vapor-locked? Add uninsulated headers near any supply lines?
Good luck with it.
Tim

 

I was searching the posts for information about fuel line fixes and I came across this post. This problem sounds like something that I'm working on. The new fuel pump isn't pumping gas to the fuel tank. I just drained three gallons of good clean fuel out of the tank, so it's not gummy gas.

I'm also working on replacing the rubber hose that attaches the fuel filler pipe to the fuel tank. The rubber hose has rotted and turned crumbly. Evidently, that rotted rubber has been falling into the gas tank. The fuel filter has bits of the rubber in it and the fuel line from the pump to the tank is plugged pretty solid. I'm probably looking at replacing the fuel lines and washing the tank out.

I'll bet this problem is what caused this truck to be retired years ago. Should be a simple, if not easy, fix.

 

i had the same problems with my 48 f-1 with a late 60's mustang drivetrain. the guy that i bought it from had a gas cap from a late model car. i asked a local mechanic and he laughed and said old gas tanks and new gas caps dont mix. i thought it was vapor lock but once i put the original style cap i stopped having the problem.. RC

 

 

I finished up the gas tank and fuel line repairs. Here's what I found, and what I did.

I pulled the driver's side running board off, undid the straps, loosened the rear running board support, disconnected the fuel line and pulled the tank out. I was able to pull the fuel line out the front without bending it very much.

When I removed the sender for the tank's gauge and looked inside, I found a pretty healthy layer of varnish in the bottom of the tank. The fuel line has no screen or filter, just a tube that's affixed to the bottom center of the tank. The fitting where the fuel line attaches to the tank was plugged up, and the fuel line itself was plugged solid.

I hosed out the tank at the quarter car wash but that didn't loosen very much of the varnish. So I put about two or three gallons of water into the tank and poured about half of a 12 oz. container of Red Devil lye (drain cleaner) into the water in the tank. While that was soaking, I worked on the fuel line with the air hose. Eventually, I was able to force some air through the fuel line. I ran some of the lye solution trough the fuel line to help clear it up too.

I drained the tank after an hour or so, then rinsed it with water. What a difference. The inside of the tank was shiny clean, the thick layer of varnish was gone. There was still a little crud in the bottom but it seemed to be stuck in there pretty good so I left it alone.

I painted the rusted running board supports with POR, then with black satin chassis paint, painted the tank and reinstalled everything. I poured a quart of Marvel Mystery Oil into the tank, added gas and fired it up. Everything's working fine now. I don't think this old 54 has been driven this much in several years. New plugs and a new plug wire and it's running smooth enough to drive.

Still waiting for the replacement filler-to-tank hose to come by UPS.