Hello all, I bought a 89 F150 4x4 with the 5L and the gas gauge reads past full all the time. It has dual tanks however the previous owner removed the rear due to the inside rusting... he claimed that the pump was the only reason the gauge always is past full but now im wondering if its due to the rear tank missing. Ive taken a look under the truck and the wiring is still all there for the rear tank. Just wondering if the rear wiring needs to be connected to complete a circuit for the gauge to work. Im going to be dropping the front tank and replacing the pump but figure I should check first if that rear wiring needs to be connected or grounded. Would save alot of time if that was the problem.

Thanks for any feedback.

 

No, completely independent wiring up to the tank selector switch. Most likely a bad sender in the tank, which you can test first and change at the time you pull the pump.

Additionally, I find it easier to just unbolt the bed and filler necks to slide it back a bit instead of fighting the dropping of the front tank.

Welcome to the forum and the basement.

Adrianspeeder

 

Thanks! Yea Im pretty sure thats the problem too just didnt want to do all the work of replacing it and finding out its because the rear tank was removed lol. Looks like when it warms up a bit ill start on it!

Thanks again!!!