I have been looking over the threads. I have one difference to most. I have just replaced the oil pressure sender. As soon as I turn on the key the gauge jumps to peg 5. The Idiot light comes on and as soon as I start the car the Idiot light goes away but the gauge is still 5+. The old unit would have the gauge either peg 5+ or 0 or even sometimes kinda work. The Idiot light would flash when idle after engine good and hot. Hence why I would like the gauge to work. The old sender looks like the original 85.5 unit. I don't trust the idiot light but no working gauge. Could it be possible I got a new broken sender? Could the wire be possibly bad? How can I check the wire? I find it weird that the gauge is 5+ as soon as the key is turned on. Any help would be greatly appreciated with this.

 

It should not peg to 5 with just ignition, try swapping the wires around.

 

I checked the wires again and also placed an ohm meter on the sender. The sender is showing variations with rpm so it has to be either the wire or the gauge. I have an odometer gear coming hopefully this week so I will check the gauge and wire to the gauge when I replace the gear. Thank you for all your help and any hints would be helpful.