No Oil Pressure

[thistle]

I have a 1963 Mark 2 2.4L which has stood in my garage for the last eight years. Following retirement I now have time to use it again. On starting the car it shows no oil pressure at all. Following research on the internet I have checked the oil pressure gauge for continuity with a multimeter ( it read 26.4 instead of zero). I also removed the wire from the transmitter unit and grounded it on the chassis and this caused the gauge to show a maximum reading. Am I correct in thinking that this proves that the gauge and wiring is ok so either the transmitter is faulty or there is really no oil pressure? A new transmitter is in the region of £90.00 so can my current one be checked first or is there another way to check if there is oil pressure or not. I have checked there is new oil in the car and there was oil pressure last time I drove it.
Thanks in anticipation.

[Doherto]

Thistle, yes you are correct that by grounding the wire on the sender unit, a working gague will read the maximum deflection. I'm not sure about having the sender tested although if the resistance between the connection on the sender unit and earth with the engine running is zero then it's open circuit and faulty. Sorry I don't know what the resistance would be on a working sender but my money is on the fact that it is faulty. Tony D

[peterheywood52573]

I managed to connect a tyre inflator to the sender and set the regulator at 40psi. The gauge read less than 30psi. This keeps the wiring, voltage stabiliser etc in circuit.
I later bought a Y-connector and fitted a mechanical gauge down inside the engine compartment.
I'll sort it sometime.
Is it really zero oil pressure? The gauge is a bimetal device and wont be quick to respond.
Peter

[thistle]

Thank you Peter, I had some advice from Ken Jenkins to check if there was oil pressure by loosening the oil feed banjo bolt at the rear of the engine. I had oil flow and I grounded the wire to the sender to earth to check the gauge was working. It was so I have changed the oil sender with a new unit and the gauge now shows oil pressure.
Sorry I should have said that I had sorted this out, but perhaps this feed will help someone else.

[BrianG]

It's interesting to note that the oil pressure sender and gauge was eventually deleted from later XJ models due to unreliability. Its history with my cars goes like this: first XJ 40 used to read about 20 psi with the engine stationary but low 40s with the engine running (correct replacement senders were difficult to obtain at the time for some reason). Later X300 model had a similar problem, but by then the approved Jaguar service "fix" was to remove the sender and replace it with a kit containing a simple low oil pressure switch and a resistor to make the gauge read about half scale when the engine was running! By the time I got an X308 there was none of that nonsense - just the basic minimum oil pressure warning light, as with later models.