Having an issue with my fuel gauge not working, while the fuel pump works just fine.

The fuel gauge has never worked since I bought the XJ about 2 years ago, and I replaced the pump about 1-1/2 years ago with a carter unit. The gauge still didn't work once I changed out the unit, but after going through all of the trouble to change the thing, I didnt feel like taking it back apart and putting in the original unit. I have used my multimeter to confirm that 5 Volts are making it to the connector to the pump on the Dark Blue / Green supply for the gauge wiring. I then thought, maybe it's something in the new unit that was also bad in the old unit, so took the old unit, plugged it in, and confirmed both that the 5V was making it through the float wiring, as well as the ohms change while working the float up and down.

I also tried the cluster gauge reset and the fuel gauge moves and has power when I do that, so not sure that the issue is there either.

Any ideas from here? I was thinking maybe PCM, but I would assume I would have way more issues than the fuel gauge if that was faulty. Any help is appreciated.

 

What year is your XJ? (Please place in every post, or in your profile or sig line).

What do you mean by "not working"? Does it always read full? Empty? Somewhere in the middle? If the resistance changes as you swing the float, but no change on the gauge, you have either a short or open circuit in the wiring somewhere.

 

Sorry,

1999 - 4.0L.

And it always reads empty.

 

Are you getting any codes? The resistance on the sender should vary with fuel level. The higher the level, the lower the resistance. The lower the level, the higher the resistance. Always reading empty suggests there's a break in a wire somewhere.

If you're handy with a multimeter, you can find the schematics (and the rest of the FSM) here. Scroll down until you find the 1999 link. The Zip file contains all the PDF by major chapter. 8W is the wiring diagrams.

https://web.archive.org/web/20110706....com/tech.html