66 Cuda Oil Gauge
Did the guage and sender ever work correctly?
Is the replacement sender the same model number as the other one?
Please post a photo of the sender.
Are you sure your sender is for a guage and not a light?
If it was a light sender it would be shorted when engine is off and open when there was oil pressure.
This would give you some of the symptoms you describe.
Quick test... With sender wire disconnected and engine off what ohms do you read between sender and block?
Same setup with engine running what ohm reading do you get.
1. with switch on accessory or run before start the gauge pegs high
Assuming the guage works the same as temp. That would indicate a short in the wire between sender and guage
2. when I start the car is drifts to pegged low
Very odd
3. when I disconnect the sending unit wire while running or prior to start it makes no difference
Not sure what you mean here.
4. when I ground the sending unit wire the meter pegs high
That is what I would expect.
