I have a 1994 F250, w/ the 300 inline and the dual tank option. I was driving the other day and noticed that my fuel gauge was not functioning. I was wondering what the steps I can take for diagnosis would be. I was running off of the front tank, and did not try the rear tank.
Also- I have recently bought the truck, so I have not had a lot of time to work on it. The farmer that I bought it from said that he had not used the rear tank in a long time. Also, the truck sat for a year or so due to a blown freeze plug, which I repaired. I was wondering if a test that involved fueling up the rear tank and seeing if that made the fuel gauge function would eliminate any possibilities. Also, if I was to do that, is there a huge concern about crud in the rear tank fouling up the fuel delivery system? Is there anything I can do short of taking the tank out and cleaning it? What about changing the fuel filter a couple of times and sending some of that fuel system moisture eliminator junk through the system? Thanks, and sorry about the long post.

 

Try and get as much gas as possible out of the rear tank because that gunk can clog the injectors then put new fuel in it and just run the tank until empty then change the fuel filter. I just replaced my fuel pump in the tank and there was alot of crap in my tank and my truck has been sitting for almost 2 years but. But good luck with that I dont know much on the gauges and how to fix them.

 

I bet if I fill up the rear tank and run it with some moisture eliminator and change the filter a couple of times after running a couple tanks through, it would probably be okay. I still am questioning if running the rear tank would provide any significant answers with the gauge, though. Does anyone know if there is an additional fuel level sending unit for the rear tank? I would imagine there would be, considering that I see no way for one unit to sense the fullness of both tanks. I was just thinking that if I ran the rear tank, and the gauge worked, that would mean that the problem was with the front tank. If it did not work, then that would mean the problem lies somewhere between the tanks and the dash gauge. Is this the correct method of thinking?