[41 Rat]

I recently got a 82 vette and the oil pressure seems to always read 20 psi. I changed to a heavier oil and zero difference. It also doesn’t change when I drive or step on the gas. When I turn the key before starting it will go to zero then up to 20 when it starts. I just replaced the sending unit and still no difference. I unplugged it and started the motor and it shot to 80(max) psi.
Is this a gauge issue or some kind of resistor behind the gauge???

 

[johnsongrass1]

rig up a mechanical gauge, even a cheapie, on the port near the dist and come back with the results.

Also, might change the filter just in case it's internally damaged.

 

[82vette]

They have a Mylar film PCB (Printed circuit board) behind the gauges that are known for trouble. If I read your post correctly you unplugged the sensor by the distributor and the gauge pegged...I'm thinking its in that board or the gauge it's self.... Put the guage in like the guy above said to make sure your engine is healthy..

82