gas gauge flakey

[Kidd7]

I have 2000 Mountaineer 5.0. My wife was rear ended and since then the gas gauge is erratic below a half tank. Seems to be fine from half to full. Below a half tank it will move move a lot anywhere from half to empty and even to the point of the check gauss light coming on. Any insight? To get an idea of the impact the rear gate was dented to the point of binding the latch mechanism, the rear bumper pushed in some, the hitch was pushed up against the spare tire. There is no frame damage though. Thanks for the help.

 

[corkey]

may have put an irregularity into the resistor inside the tank, as the arm would have been shocked too in the crash,,

the only way to be sure is to take it out and check it with an ohm meter,

 

[koda2000]

the shock of the collision must have damaged the rheostat in the sending unit. you can remove the fuel pump assembly and test the range on the float with an OHM meter to be sure, but you'll probably need to replace the assembly to get the gauge to work correctly. i had a vehicle whose fuel gauge worked in the same way. it was okay above 1/2 full and would drop to E below 1/2 a tank.

 

[Kidd7]

"replace the assembly" being the fuel pump? Do you have to drop the tank to access the fuel pump on these trucks?

 

[koda2000]

"replace the assembly" being the fuel pump? Do you have to drop the tank to access the fuel pump on these trucks?

the assembly includes the fuel pump. you can replace just the pump, but the assembly has the sending unit for the gauge.

yes, you have to either drop the fuel tank, or cut a hole in the floor to change the fuel pump assembly (or the pump).

 

[Kidd7]

Thanks for the info guys; what size tank would be in my truck?

 

[koda2000]

it should be stamped into the tank (they're at the rear as i recall) there should be a bunch of numbers and something like 20Gal or 17Gal.