96 f-150 4.9L/ 300. One fuel pump quit working last year. I have not fixed that problem yet, but now have a new issue. After a short drive I smelled gas as I opened the door. Fuel was pouring out of the gas cap on the front tank(the fuel pump is not working on this tank). I opened the cap and a lot of pressure released and the fuel stopped coming out. I opened the cap on the back tank and it had some pressure also but no fuel coming out? Any ideas? I will be checking fuel pressure and plan to check front fuel pump.

 

Also what is correct name for solenoid or relay that switches tanks. Is it located on the frame or is it all part of switch on dash?

Thanks for any help and ideas.

 

There is a pilot-operated check valve in the fuel delivery module (i.e. fuel pump assembly)
It blocks return flow to the tank whose pump is not running. When the valve malfunctions, it allows fuel to transfer from the tank you are using to the tank which you are not using.

Since you need to replace the front pump assembly anyway, do it and that should solve the problem.

The switch on the dash is called the "Fuel Tank Selector Switch." There is no other switch or relay

 

Like Strange says, on your year, the tank that you select is the pump that gets power, and the check valve closes on the other tank from the non running pump.

Adrianspeeder

 

Thanks for the replys. I will hopefully be replacing front pump soon.