F-350 fuel problem

Given age of vehicle lot for possible a cracked or broken fuel line. THe last dual tank system I had years ago actaully switched feed from tank to tank and did not transfer fuel around but on that model yearI am not sure.

----------------- TheSnoMan.com

I have a 86 F350 so the fuel system should be similar. I had the same problem but with the rear tank. I discovered the gauze filter on the pickup in the tank was blocked with slime and would not let fuel pass. The pressure from the low pressure tank pump activates the valve mounted in the left chassis rail under the cab. No pressure from tank = no changeover. I took the pump assembly out and cleaned the filter and it all works perfectly now. Although I would suggest getting new filters and doing both tanks while you are at it. I am in Australia and ford parts are very expensive or I would have chosen this option. Hope this helps.

woodee

snipped-for-privacy@yahoo.com wrote:

The selector is really not mechanical or electrical. It's actuated by the gasoline from the pump that's running. Pressure from the pump kind of moves a valve for you. There's no connection between the gas gauge working, the pump working, and the valve working. All separate systems that work together at the same time if all goes right.

So, that said, you don't know which is at fault. It's not much help, but it's the truth. I would suspect the in-tank pump (or the sock, as somebody else suggested), but I don't see a way to pressure test under the truck, so you may have to trial-and-error a little bit.

Thank you SnoMan, Woodee and Joe. I have a better understanding of the system now. I think the in tank pump is the likely culprit. I'll drop the tank and check for power leading to the pump first then assuming I find no trouble there I'll pull the pump and deal with it as well as the filter. You've all been a great help. Thank you again.

Carl

snipped-for-privacy@yahoo.com wrote:

While you're at it, buy new gas caps. I have a '93 that had the same problem, gas cap wasn't venting creating a fuel lock when I tried to use the front tank.

Moon