I hooked up a digital multimeter (DMM) to the wire coming off of the sensor, and then to ground. The sensor is plugged into the wiring harness also by the way. I wanted to get some numbers over a short time to see how quickly the ohms drop as the head heats up.
So, engine off, ambient temp is around 67 deg. F. Sensor reads 2945 ohms. My understanding is that this is normal.
Turn the key on and the multimeter reads nothing, open circuit I think it's called. Wasn't expecting this.
Start the engine and run it for a minute or two, multimeter still reads nothing. Turn the key off and now I get a reading of 506 ohms on the DMM.
So, turn the key to on (reads nothing) and then I switch the multimeter to volts DC and I have a reading of 2.584 volts while the key is in the on position? Is this normal?
I was thinking I could just watch the resistence drop while the engine is running.