Hi,
I have a question about my oil pressure in my car. It almost seems like it is an on/off switch. I start up the car and the gauge needle jumps to 3/4 and only moves again when I shut down the engine. Is this normal?
Thanks!

 

Normal

Jaguar configured the gauge to give a fixed reading.

Same for the temp gauge, almost. The temp gauge is calibrated to give a fixed 'normal' reading over a wide range of temperatures. At some point....not sure what it is....the needle will move over to "hot"

On my X300, using a scan tool for actual temp readings, I found that the needle hit "N" at about 170ºF and remained fixed until at least 210ºF.....which is the highest coolant temp I ever measured with the scan tool

Cheers
DD

 

It may, in fact, be a switch. 8 psi, I believe. Jaguar had much trouble with the oil pressure transducer and eventually switched over to an 8 psi switch for the sensor unit, mounted near the oil filter. A "fix kit" was offered consisting of the switch and a resistor for retrofit of the troublesome transducer.
A search will yield threads with pictures of both.

 

It's a 'FORD THING'.
Ford switched to a switch in the 1990s so Jaguar did too!!!!!!

bob