7.5 1994 F-350 4x4 Cross Tank Fuel Flow Condition

[toddye4]

7.5 Liter 1994 F-350 4x4 Cross Tank Fuel Flow Condition.
Switch on dash: rear tank stopped working.
Front tank fills rear tank tell overflow.
Today, engine off key on, dash switch to rear, to check gas level in rear tank. I heard fuel pump kick on for start up???
Started and drove approx 20 miles.
Engine off, tryed to rest start in rear tank, no go.
Only front like before.
Please Help.

 

[Fellro]

Technically, unless the engine is running, neither pump should be running for long. There is a check valve that keeps the fuel from going to the opposite tank from what is selected. If it is stuck open, it can let fuel go to the other tank.

 

[dustybumpers]

Check valve is bad as stated above. There was a recall years ago that covered this, but I think it timed out, due to age. It was basically an external check valve Ford put in the line at the tank. You still see them on tanks in the junkyard from time to time.

the other problem, with the rear tank, my 94 has a loose connection to the back of the tank switch in the dash. It works fine if you push all the connections tight. Just don't hit a bump with the front tank empty, or you're going to be taking my dash apart. and pushing the pins back in the connector.
I need to repin the connector, just haven't gotten around to it, and I bet yours is the same problem

 

[toddye4]

Wow !!!
Thank You So Much for your input.
Going to check dash switch now

 

[dustybumpers]

Be careful taking the dash apart. you have to take the 2 trim pieces off to get to the screws under them, then just snap it open. if you try to pry it open without removing the screws first, the plastic will break, and it will NEVER stay in place again ( Don't ask me how I discovered this )

This is a great time to clean all the dust from the gauges that you normally can't get too