Alright...this is definitly throwing me for a loop...I have an '84 F-150, strait 6 300,4-spd granny,dual tanks... OK, gauges-back, has always been fine, front, never worked, always pegged at max. Bigger problem...i had filled both tanks up about a week or so ago...thats about 38 gallons, more than a week of gas (for me anyway...) I usually run off the back becuase the guage works, but, i decided to run off the front for awhile, jsut use up any gas thats been sitting in there etc, when it ran out, or sputtered at all, i'd switch to the back and be good to go. Well...last night it started to die, i hit the switch to go to the back tank, and my heart sank as i saw the guage now drop a little past E, (yet I never used the back tank for any significant period of time since last fill-up). Well, i was close to home, got the gas can, put some in back tank, made it to gas station...filled up the back tank, went to fill the front....guess what? less than a buck of gas went into the front before the pump clicked off. I got under the truck, tapped the front tank, sure enough, it was full already. So...problems, front tank gauge doesnt work, and now it seems i cant get fuel from it either, gas is drawn from the back no matter what tank the selector is on. Help!!! Please!!! Why is it happening? A fix? Anything....
Eric
and thank-you

 

Eric, Have you changed the filters BEFORE the fuel switching soleniod?
also, Could be the solenoid is not shifting to get fuel from the front tank.solenoid should only be powered in one direction...usually to the aux. tank. then return to `main`tank(home) with the power off.
mine anyway

If you pull the wire from the sending unit at the tank and ground it the gauge should go to full.



__JOHN__ô¿õ
1972 F-250
ICQ# 6030753

 

Filters? I pulled the wires that go into the top of the front tank,(there are two..) bridged 'em, and the gauge went to full (like it always is).

 

I had a similar problem, but like some other things on my truck, it fixed itself. But I spent some time studying the problems and found out that each tank has a low pressure pump in it and if it goes out, or theres no power to it, then there's not enough pressure to change the tank switch solenoid. That's how it changes tanks, one pump comes on in the tank and the other goes off. I understood it like that.

P.S. My 88 with 187k miles has always had a guage that stays on full until the last 3-4 gallons, then it starts dropping to what it should be. I use my trip odometer to keep track of fuel.