I have an 88 F-150 that I think the tank selector valve is gone. If I have two full tanks, the tank I am not using overflows. In otherwords, it is returning fuel to the opposite tank that is in use. Anyone know the part number for this valve and where to get it. I have toyed with the idea of putting a manually operated valve in it's place.

 

Most likely one of the intank pumps is bad. The selector valve is mechanical and switched by the pressure from the intank pump.

Part # f1uz9b263b Dealer sells the selector valve for around $71.00.

 

It runs good on either tank.

 

Here is a link to a post that Subford gives a great solution for. This is a common problem with our trucks. Be sure to add to his rep points if it helps you.

https://www.ford-trucks.com/forums/5...dual+fuel+tank

 

My truck is aqn 88 model and the tank selector valve is on the frame rail. There are no valves in the tanks.

 

i have a 92 f150 xlt 302 engine efi, my tanks been doing this for some time.. hasn't quit on me but there is a selector/ proprtioning valve from what i gather.. truck runs great on either tank.. does fluctuate alot but no serious issues yet.. changed filter and regulator and relay.. next .. proporting selector valve and if has check valves.. replace with after market deal.. gets job done and less expensive..

 

My 1997 F-250 did the same things last year. I was told that the fuel pump needed to be replaced, which did correct the problem. However, it makes me sick to think that I could have replaced the valve for only $71.00... as opposed to the $460.00 I spent replacing the fuel pump. Ug...

 

Here's one method to verify if each in tank pump is pumping the proper volume.

Note: I do understand you said both tanks seem to be working properly except for the dumping of fuel into the tank not being used.

On the back of the selector valve are four hoses. The two larger diameter hoses are the output from each in tank pump. The two smaller ones are the return lines. You can trace the hoses back and tell what tank they go to.

To remove a hose, you can use a small flat blade screwdriver and pry up on the retainer clip half way up. The hose will then pull off. (When you're done, push the clip back down, then push the hose back onto the slector valve). Tug on the hose to verify the clip holds the hose on the selector valve.

Place a larger hose over the ouput hose and the other end in a container.

Under the hood on the driverside plastic fenderwell towards the back you should see the Diagnostic connector. Ground the pin show in the diagram. Turn the ignition on.

(If you don't want the fuel rail mounted pump running during this test, disconnect its electrical plug. It's a little pigtail plug right at the pump).

The selected fuel tank pump should stay running.
In 10 seconds the pump should pump at least 16oz of fuel into the container.

You should do this test before purchasing a selector valve.