1989 econoline custom noticed fuel leakage at front tank filler tube and vapor tube at tank connects. tightened hose clamps still leaks. While switch was off and both filler caps removed fuel began to roll out of front tank filler tube i started engine and upon switching to rear tank fuel stopped running out of tube until i switched to front tank again everyone i know now thinks i am insane any help

 

Welcome to the forum! I don't know for sure how is your arrangement with two tanks, but I know that there is a return fuel line from the engine, through which the excess gas pumped to the injectors is sent back to the tank. I wonder if your fuel pump isn't actually sucking gas from one tank and returning it to the other ... I'm just guessing here, hopefully the more experienced people here could comment. Good luck, and let us know what you find!

 

Mr cougar_fan I think you hit it on the money.
I was trying to sort out the details of Mr Dambrosio's post and could not say for sure if it was caused by the switching valve under the vehicle. The switching valve is operated by fuel pump pressure . For example, if the rear tank is selected, the pressure from the line from that tank should cause the valve to open the supply to the engine and the return from the engine is supposed to go to the same tank that is pumping. When the valve malfunctions it can send the returning fuel to the wrong tank. From what I read in the post , that wasn't quite what was happening, so I hesitated to suggest a solution until I was sure of the exact information. To locate that valve is pretty easy. It has 4 lines coming to it , 2 from each tank,a supply and a return. There should be only 2 lines going away from the valve, the supply to the engine and the return from the engine. That set-up was for the Econoline models. I believe the valve may have a filter inside and can be opened to be cleaned. It's been a while since I have played around with them.
Maybe someone can shed a little more light on the situation.

 

Ok guys, I'll bite. This did have the fuel switching valve on the frame, and they did stick all the time. And sometimes, they did leak. I would just say that this really is one of those "NO User Servicable Parts Inside" times. They should be replaced when suspected, and please dont take it apart to clean it. NEVER take the chance with gasoline, as it can burn the car to the ground in less time then YOU can get out of it!
Also, check for any cracked nylon tubing, especially where it goes betwixt the tank and frame. On something this old, it would have a good chance of being damaged.