gauge problem

[matt25]

so i dropped a new motor in the jeep. one small problem the oil pressure gauge is needled out to the top and the temp gauge doesnt even read. im assuming the oil sending unit is bad for the oil pressure gauge. but the temp is confusing me i traced the wire and there are no breaks and the unit is new. could my thermostat be bad and thats what is causing it not to read. or could it be a fuse. im stuck on this one

[90xj06]

if the sending unit is bad it will go to the far right side past 80#

[jrock]

If the donor Jeep had idiot lights instead of actual gauges, the senders will be incorrect for the temp and oil. You could try swapping in your old ones.

[8Mud]

With the wire *disconnected* from the oil pressure sender and power to the gauges, the needle will read full right or an open circuit with power to the gauges. On my Renix.
With the wire *disconnected* from the temperature gauge and power to the gauges, the needle will read all the the way to the left. On my Renix.
The gauges will pretty much stay in position, when the fuse blows. So if the wires were disconnected and then the gauges were powered up and then the fuse blew. They may show, near full right for the oil pressure and nearly fully to the left for the coolant temp. with the key on or off. The gauges (temp. and oil pressure) often move some when the key is turned of, but have a tendancy to stay near where they were when the key was turned off or the fuse was blown.
I've used a short jumper and grounded the sending unit wire to a handy ground for an instant with the key in the run position and had someone watch the gauge, the needle will jump or peg in the opposite direction. I just quickly flashed the ground, I've never held it on there long.

[jeeperzcreeperz]

I'm having the same problem with my oil pressure gauge, but its been in the jeep for a while now. Just went way past 80 the other day and i've tried a new sending unit still didnt help it any.