Just like the title states, i have a pegged out oil gauge. When i turn the key it just climbs to past 80. When i turn the key off, it slowly descends. I have unplugged the the oil sending unit to see if the gauge would fall but it dont..What are your thoughts?
Not an electrical expert here but have a friend that had the same thing happen on his XJ and it was the sending unit. I am guessing here but I would think that if you unplug it then it may show pegged since it is not getting any signal to tell it otherwise.
We replaced his sending unit and fixed the problem. It is really common on the XJ's with the 4.0L so I figure it may be common on YJ's as well. I think it was about $50.00 at O'Reilly's.
Changing sending unit is a 5 min job, located right above the oil filter, just unplug wires unscrew old one and screw new one in and plug wires back up. That would be a lot simpler and you should have your original gauge working again.
If you remove the plug from the sender unit, the gauge should drop to zero. As you've tried this, and it stayed at maximum, I'm thinking you have a shorted wire, or were unsuccessful in cleaning all the corrosion from the gauge cluster.
I have a '99 with the same problem, and mine goes to 0. CJtim states you should only use OEM's for these. I'm waiting a quote. Regardless, I'm not going to pay more than 40 for it.