When I switch to the front tank on my gas burning 1991 Ford F-250, the gauge drops to empty and continues to pump from the rear tank. Selector switch? What? Help!

Asked by Jan 10, 2014 at 04:43 PM about the 1991 Ford F-250

Question type: Maintenance & Repair

6 Answers


You will have to buy both Fuel pumps from ford. Complete pumps.Aftermarket won't fix the problem. The metal lines that the fuel pump attaches to have a check valve in them. The check valve has deteriorated on yours. They also have a second check valve that locks on the new fuel pumps that will need to be purchased/installed too.Ford will have these when you buy the pumps.


The front pump sending unit float is made of brass. It has a pin hole in it and is full of gas causing it to sink and read empty. These will be included with the pumps.


Wait! Is the rear pump pumping gas into the front tank?

5 of 5 people found this helpful.

I do not think so. This problem showed up after I filled up both tanks. The front tank stays full and the rear tank seems to empty out at a normal rate.


Disregard my first answer then. If it is just still running on rear when switched to front the selector switch from front to rear tank is bad. The float in the front tank is bad.Just the brass part. Cost about $10 bucks at ford.

1 of 1 people found this helpful.
Best Answer Mark helpful

I have a 1991 Ford F 250I just put the engine in itI can't hear my two rear fuel tanks workingwhen I turn the key on the fuel gauge says full

2 of 2 people found this helpful.

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