My truck is a 92 F250 Longbed 4x4 5.8L 4x4, When i use my rear gas tank the gage reads empty after about 100-110 miles traveled. Had calculating my mileage I get about 12 MPG.

So the question is, is this normal for this generation truck or is it just my sending unit is whacked?

Whn i bought the truck the front tank sending unit didn't work. I replaced the front tank sending unit with a junkyard sender and it works good and actually tranks fuel consumption fairly accurately, full when full, 9 gallons used at half, and about 18 gallons used when empty.

Matt

 

But is the tank actually empty at that point? Engine fuel consumption can be no better or worse on either tank so if both have similar capacities but you can't go nearly as far on the rear then it's likely you have the fuel transfer problem where gas is being pumped into the front tank and overflowing out onto the ground if it's full while you're using the rear.

 

Your sending unit is bad

 

I agree.

To make sure, fill both front and rear tanks. Drive on the rear tank until empty and see how many miles you traveled.

My guess it is more than 100.

My '85 did the exact same thing. I kept a 2 gal gas can with me as a new sending unit was worth more than the truck itself..

The rheostat that measures the fuel wears out in the places that it rubs on the most. Some people have pulled the tank and bent the pointer to move it on to a fresh piece of circuit board.

 

No the tank is not empty, I have been driving last 30 miles on an empty tank. The actaul fuel consumption on either tank when hand calculating is consistant between both tanks at 12MPG combined.

I figured the sending unit was bad just thought I would see if it was normal to read emapty with a half tank on these. I figure when I fill up the rear tank i will drive 160 to 180 miles on it then switch to the front tank that has a functional fuel gage before filling up again

Matt