Gas Guage
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Joined: Nov 2004
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Gas Guage
Just bought an 2001 F-250 SC 4X4 V-10. When I fill the truck up the gas guage only reads 3/4 full. Therefore leaving me guessing when the fuel is actually low. Just wondering if there is a way to test the gas guage before changing the sending unit. And If it is the gas guage , how to go about repairing it. Thanks in advance.
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Joined: Jan 2001
Posts: 57,023
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From: Virginia
99% of the time on the older trucks it's the sending unit, not the guage. I think I would experiment a little bit before I started tearing it apart. Why don't you let the guage get low, and then carry a 5 gallon can of gas with you. Let it run out, and then fill it back up with the can. Or you could try to siphon the gas out. I would try to figure out is the guage scale shifted, or is the top end just gone.
If you had 10 gallons left when the guage read empty, I guess that would get aggravating, but if the guage read ok on the lower part of the scale, and just did not properly read a full tank, I think I could live with that.
If you had 10 gallons left when the guage read empty, I guess that would get aggravating, but if the guage read ok on the lower part of the scale, and just did not properly read a full tank, I think I could live with that.
Moderator
Joined: Jan 2001
Posts: 57,023
Likes: 2,754
From: Virginia
Take the wire off at the tank that goes to the sending unit.
If you have an older truck, it will be obvious which one. If you have a system will the pump in the tank, it will have a few more wires to sort through.
Once you find the wire that goes to the sending unit portion, take it off, and with the key in run, ground the wire to the frame. The guage should swing all the way full scale in one direction. Then take the wire off ground, and the guage should swing full scale the other direction. If this test works, then the fuel guage and wiring are ok, and there is something wrong with the sending unit in the tank.
If you have an older truck, it will be obvious which one. If you have a system will the pump in the tank, it will have a few more wires to sort through.
Once you find the wire that goes to the sending unit portion, take it off, and with the key in run, ground the wire to the frame. The guage should swing all the way full scale in one direction. Then take the wire off ground, and the guage should swing full scale the other direction. If this test works, then the fuel guage and wiring are ok, and there is something wrong with the sending unit in the tank.
