Re: Oil Pressure Gauge
In my 90YJ, when my oil pressure sending unit went bad, it would peg the gauge as soon as I turn the key on also. Are you sure you're disconnecting the pressure sending unit? I don't mean to insult your intelligence, but the pressure sending unit is the small can with a single prong sticking out the top that is physically located between the distributor and the fire wall. I think what is confusing me is that you say that when you disconnect it, the gauge stays pegged. How can it stay pegged when you say it pegs as soon as you turn the key?
If the gauge is not mechanically stuck all the way to the right, then I would replace the gauge. If the gauge is moving thru full sweep (key on and off), then replace the sender.
BTW, when I replaced the sending unit, everything works great. Good luck.
90YJ 4.2L NV4500 456:1 33's Twin ARB's