i have a 1984 f150 with the inline 6. the gas gauge does not work. does anybody have a clue on how to fix it or how much would it cost to fix it? just give me some ideas of what i should check.

thanks
dwayne

 

Take the wire off going to the sending unit on top of the tank. With the key on, put the wire on a good ground and watch the guage. Then take the wire off the ground and let it hang. When you do this, you should see the needle sweep back and forth depending on if the wire is grounded or not connected to anything. If this test works, it means the wire and the guage are ok, and there is something wrong with the sending unit in the tank. There is also the possibility the tank is not grounded very good, so check this too. If this checks good, pull the sending unit out. If you want to, sometimes the sending unit can be fixed. Take some needle nose and carefully bend back the tabs on the unit's housing and pull the cover off. See if the wiper is contacting the coiled wires. If not, or if it is cracked, it can be soldered and it will work like new. You can test it before you put it back, by hooking the tank wire up, and ground the metal part of the sending unit. Then swing the float back and forth and watch the guage needle.

 

if you do replace it...don't buy a new one. get something out of a junkyard that someone has forgotten about. my '85 fuel gauge never worked. my dad and i pulled the sending unit out of an '82 F150 and put it in my rear tank.
If you can't find one to match your '84, another F150 unit will work. The catch is the tank design changed over time. So, you have to make sure that it is in the correct position at Empty.

We just bent the arm and placed the unit back into the tank. When it hits the bottom, just bend it up a bit more and you should be good.

On the '85, there were a series of conducting strips to send the signal to the gauge. Kind of like this....
_______________________
|||||||||||||||||||||||
_______________________

Those vertical lines should go all the way down, but I couldn't figure out how to draw that.
Anyway, overtime the lines get scraped by the contactor scratching over them. Mine had been scratched together on the front tank, but it still sent some unpredictable and signal. I just got my pocket knife out and cleaned off the solder that was now bridging the strips.

good luck,
wes