After finding out my off-the-shelf oil pressure sender is not accurate I did some research and found this site:
Then bought an Autometer 2242 and installed it. The unit is tall so I used a brass 45 and an adapter to plumb it. I used the correct sealant (not teflon tape or plumbers teflon) and get 0 Ohms between the sensor tightening nut and chassis ground.
I have a good engine ground.
My gauge will not work with this sensor. When the engine is running it barely moves if at all. I tested it by grounding the sensor connection and the gauge slowly moves past H as expected.
The resistance between the sensor post and chassis ground is 254 ohms (corresponding to 0psi) with the engine off and the gauge disconnected. Repeatable. At warm idle it measures about 130 ohms (35psi) and at higher engine speed about 95 ohms (55psi).
These values change when I turn the running lights on. Ohms decrease to about 148 with the engine off. Repeatable. Again, the sensor isn't electrically connected to anything other than the engine, and my ohmmeter.
If the engine is running and gets hot enough to turn the electric fan on, the resistance goes up in the mega-ohm range.
I have no clue what is happening. As you may know, I have done extensive electrical modifications to this car, but everything is working (except the fuel gauge, and that demon is next!).
I can't find my old sensor so tomorrow I'll buy a new one and try that.
Then bought an Autometer 2242 and installed it. The unit is tall so I used a brass 45 and an adapter to plumb it. I used the correct sealant (not teflon tape or plumbers teflon) and get 0 Ohms between the sensor tightening nut and chassis ground.
I have a good engine ground.
My gauge will not work with this sensor. When the engine is running it barely moves if at all. I tested it by grounding the sensor connection and the gauge slowly moves past H as expected.
The resistance between the sensor post and chassis ground is 254 ohms (corresponding to 0psi) with the engine off and the gauge disconnected. Repeatable. At warm idle it measures about 130 ohms (35psi) and at higher engine speed about 95 ohms (55psi).
These values change when I turn the running lights on. Ohms decrease to about 148 with the engine off. Repeatable. Again, the sensor isn't electrically connected to anything other than the engine, and my ohmmeter.
If the engine is running and gets hot enough to turn the electric fan on, the resistance goes up in the mega-ohm range.
I have no clue what is happening. As you may know, I have done extensive electrical modifications to this car, but everything is working (except the fuel gauge, and that demon is next!).
I can't find my old sensor so tomorrow I'll buy a new one and try that.
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