I just bought a 1994 F250 Turbo charged (non-power stroke) supercrew with about 213K on it. The truck stalled on me the other day and I was able to get it restarted. I thought maybe the tank I had switched on was low on fuel. I put about seven gallons a fuel into each tank and the gauge for the rear tank gauge reads well beyond full and the front tank gauge reads about 3/4 full. Is this a common issue and is there an easy fix? Could I just run the rear tank to empty and use the front tank exclusively?

 

Yes this is common as all get-out. I had the same problem on my '88 7.3 IDI when I bought it, and I still do. There is a combination of things going on here (all of this I have learned from the forums here, and if I'm missing anything or getting it wrong I hope someone will chime in and correct my asp):

1. Old and poorly grounded sending units do not give you accurate readings on your fuel gauge. You may be able to clean up the grounds which may help a bit, but I have gone to keeping track of how many miles I can go on each tank before switching. As in, I am my own fuel gauge (until I fix it). My gauge also reads WAY above full when they are full.

2. The pick-up tube in one or both tanks tends to, well, FALL OFF or become useless at some point during these truck's lives, and you have to drop the tank/remove the bed and take off the sending units and add your own pick up tube so you can get all the fuel out of those monster tanks. Search the forums for how to do this. Midapo just did a nice job on his with pictures.

I have both of these problems, so I had to actually run out of fuel before I knew how many usable gallons I had in my front tank. Rear works fine. I am planning on removing my bed and gettin' in there soon.

 

And if you're anywhere near fullerton maybe we can help each other out. Those beds are somepin like 400 pounds and you needs some extra hands.

 

the main culprit of the 2 trucks i had issues with was the FSV.
i replaced the FSV on one, problem fixed.
i deleted the front tank on the other, wired up the sensor and it works flawlessly.

 

Thanks for the information. I will try cleaning up the ground on the FSV

 

im pretty sure the ground on the FSV goes into the switch on the dash.

alot of people tend to not want to replace this part because of its cost.
it is pricy.

i firmly believe that if i would have replaced it on my 2nd truck, it would have solved the issue i had, but i customized my cab, which led me to delete the front tank all together.

 

There is no ground on the FSV. Two wires on the FSV go to the switch. Those two wires carry 12V either in one direction or the other (the valve works by polarity). That's what operates the valve. The other three are for the sending units. One wire to each tank, and the third wire to the gauge head. Diagram is worth a thousand words...: http://userpages.chorus.net/elephant...nkselector.pdf . The past-full reading on one tank only means an open circuit from that tank's sending unit. Could be that terminal on the FSV (terminal 6, yellow/blue wire), or that wire going to the rear sending unit. Or the ground wire from the sending unit (the tank itself does not ground) has a break somewhere.

The fact that the gauge changes **PROBABLY** means that the valve is switching properly.