Fueling and Fuel tank problems

[Billy Goat Burner]

Why does it take 25 min to fuel the tanks on this truck? I mean you have to let the fuel almost drip in! and I noticed that when I have about 1/8 tank of fuel and drive or stop I lose fuel to the fuel pump which kills the truck or makes it hesitate, anybody else have this problem?

 

[GenLightening]

First, pretty sure there's a tech article on how to modify the tank breather. Or place a block of wood under the rear tire on one side. Second, there's a plastic pickup tube that tends to break off in the tank, usually you run out at 1/4 tank. Adding a section of hose with a V notch helps it draw from the bottom of the tank.

 

[Full Monte]

Look for posts on "Harpooning a fuel tank". The problem is that the venting of the tank for fuel filling is done through the filler neck. The vent tube is a flimsy plastic thing. Sometimes it kinks inside the filler tube at one of the turns. The best way to fix it seems to be to replace the vent tube with one that runs externally from the top of the tank to someplace high near the fuel cap. See the articles on how to do this.

 

[MIDNIGHT RIDER]

Why does it take 25 min to fuel the tanks on this truck?

There may be a difference in the plumbing of your 1990 tanks and my 1985.

When I first got my truck, way back in the good old days, it would puke fuel out and all over me when filling; it took forever to get a few gallons in.

I monkeyed with the vent-hose that rides up the filler-neck and it helped a VERY LITTLE.

I crawled underneath and examined the tanks and found that the tanks have a SEPERATE GENUINE VENT HOSE, 7/16 I.D., shoved into the tank through a rubber grommet and protuding about two inches into the tank.

Attached to the ends of these vent-hoses were plastic roll-over-protection loose-ball valves, with more air restriction than a kid's toy whistle.

I removed those plastic obstructions and threw them in the trash, covering the hose-ends with little window-screen socks.

After that little modification, it would nearly suck the hat off my head and into the tank, the fuel would go in so fast; I could even use the rapid-flow big-truck pumps and not spill a drop.


A couple years ago, I routed all new 1/2" I.D. vent-hose, TEE-ing the vent-hoses of all three tanks together, and having it terminate up high and dry at the top of the head-rack in a down-ward pointing horse-shoe bend.

I did this because before, due to heat-expansion, sometimes a very full tank would expand and push fuel out the vent; all TEE-ed together and having a lot more hose to fill, the expanded fuel never makes it outside the system, draining itself back into whichever tank has room for it.