Gradyw

I have a 1999 XJ with an odd issue regarding the fuel gauge. Recently I had an issue with the crank positioning sensor shorting out, not allowing my gauges to show any signs of life nor my fuel pump, leaving me at a nice Publix parking lot 👌 . After I installed the new CPS, the Jeep has been running fine minus the fuel gauge doing its own thing. I purchased a brand new fuel module today, plugged it in as a control to rule it out of the equation, and you guessed it that didn't make a difference, it still will go from full to empty randomly... I seem to have clean power & ground going to the ECU as well as the plug going to the fuel module. The Blue/Green wire at the plug is giving me a reading of .70 volts when the gauge is pegged full, thus leaving me to believe its not the ECU that is the problem. I am also getting an SC code on my overhead console on DTE but only when the fuel gauge reads empty with no gas light other wise it says 311 miles. Anyway I could be wrong in my diagnosis, but I cannot seem to find another person that has had this particular issue. THIS ISSUE WILL OCCUR PARKED OR DRIVING RUNNING OR NOT. Not sure where to take it from here hoping someone can help!


*Another odd issue that came up after the CPS was installed, the IAC started giving me issues and I am unable to remove the code. I am going to get a new one tomorrow to see if that will straighten out and stop trying to rev up past 2000rpm on its own lol*


Thank You.👍

4.3L XJ

That means the fuel gauge circuit is finding a full ground instead of the partial ground through the float in the tank. You will have to find the short

Gradyw

I have a feeling it’s the ECU because I have a check engine light with no code and I’m still having an idle issue I’m going to replace that and go from there.

4.3L XJ

OK