Baystate Jeepers

Looking at putting a gas gauge on the dash. Tired of the dip stick in the tank thing. Looking at a Stewart Warner electric gauge and sending unit. I have a YJ manual sending unit in the fuel cell that will not tell the gauge in my speed-o cluster how much gas is in the tank. It must not be compatible as Ive just replaced the sending unit with a brand new one. Any way to be sure before I go this route ? Thanks FjR68

Frank,

Which YJ sender are you using? One with just the pickup and level sensor (carb versions) or one that also has the electric fuel pump (EFI version)?

The fuel sender has to be grounded to work.
The YJ sender resistance values are ~1 ohm to ~88 ohms.
~1 ohm when the tank is Empty,
~44 ohms when half full
~88 ohms when Full.

edit:
Did a bit more digging. Looks like the stock CJ fuel sender uses the following resistances with respect to how much fuel is in the tank.
Empty = 73 ohms
1/2 Tank = 23 ohms
Full tank = 10 ohms

Basically backwards from the YJ sender.
So.... If you had your stock CJ fuel gauge wired up to the YJ sender (and there was no bad wiring) your CJ gauge would read ~Empty when the tank was Full and ~Full when the tank was empty.

What is your CJ gauge reading when your tank is empty or full?


Here is how to troubleshoot the stock CJ gauges ---> http://home.roadrunner.com/~john.strenk ... cj_gau.htm

Well it did just that at first Kurt . Empty when full. I switched the wiper to the other side and in my hand it worked as what I thought it should. Full to empty. Its the carb one. Pick up and level. When I filled the tank the first time the gauge was almost full and by the time I left the station it was on empty , never to work again I got a new sender from Santa and tried it again in the yard with no response from the dash gauge. There is one wire that goes to a stud and goes to the harness for the gauge. There is a spade for the ground which is hooked to the ground for the electric pump. I ordered the S.W. gauge and sender and will drill another 2/16th hole right next to my other white faced gauges. (for us old blind guys) Im gonna have the rectangle hole filled from the YJ sender and drill a 2" hole for the new sender. Thanks for the info and research. FjR68