Fuel Sending Unit Problem

[MrMilks]

Hey guys, My truck was reading 1/8 of a tank for 3 weeks and its my daily driver so we all know they don't work like that . Any way So I ran it dry and dropped the tank and swapped the sending unit to see if that would solve the problem, well it didn't and I have no idea what the issue could be. I dropped the left tank and only use the right hand tank, could that cause a problem? Also a while back it wasn't sending fuel to the motor so I bypassed the unit that is used to swap between the two tanks and ran a line straight from the right hand tank to the motor and that solved the problem of not sending fuel. Could have bypassing that unit have caused this issue? Any ideas would be extremely helpful.
Thanks for your time.

[notyo_cheez]

Can't remember, there's a pink wire that if I'm not mistaken is the feed from the selector to the fuel gauge. When tanks are switched the corresponding sending unit circuit closes as well. Since there's only one tank on it now you probably want to bypass the selector. Also check your connection to ground from the sending unit.

[wilkin250r]

Sounds like you might be able to solve both problems by replacing the fuel selection valve.

On the earlier models, the electrical signal for the gauge happens at the switch on the dash. It controlled the circuits for the sending units, and also send the signal to the valve below for the actual fuel lines.

On later units, it ALL happens at the valve below. The valve not only controls the flow of fuel, but the valve also controls the switching of the electrical circuits for the fuel gauge. Personally, I have the earlier model, so I don't the characteristics of the later models when they go bad.

[Desert1957]

Maybe this will help you with the wiring.



Desert