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Hello, After hibernating for almost 18 months due to Covid I'm now working on getting my 1988 Bentley 8 (24724) back to life. It needs a new oil pressure sender and I've read that the later sender (UD72639) can be used rather than the more expensive and less-reliable one (UE40480P) which is the correct replacement.
I bought the later one, with two contacts rather than one and it does not work - the oil pressure gauge rises to maximum when the ignition is switched on (engine not running.)
When testing the new sender on the bench the 'WK' oil warning light connector shows no resistance when connected to sender body. Which I would expect. However the 'G' oil gauge connector also shows no resistance when connected to the sender body. I would not expect this - I would expect an open circuit which would show as zero oil pressure. Could the sender be faulty?
IntroCar, who supplied the sender, have put me in touch with a RollsRoyce mechanic (I have no idea where from) who says the two senders are completely different, made by different manufacturers, can not be interchanged, and that I should get the correct sensor. Although he admitted he has never tried swapping the senders.
Any thoughts?
Many thanks, Theo.
 

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I fitted one once and got the terminals mixed up and got the same as you. I never could find a wiring diagram with this type of sender.
Mike
 

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Unfortunately all manuals that I have mention only pressure senders with one connector. I cannot help.

Anyway, Do you have oil pressure gauge in model "Eight"?
 

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I don't know on your car but my 99 Arnage uses a 4-20mA pressure transducer to feed the gauge. You can buy one from Bentley parts suppliers for hundreds of dollars or you can buy a generic one for less than $20 +shipping. I used one 9-32V, 4-20mA, 0-10bar I found on Amazon. It has two wires, red and black. The red is 12V and black ground. I had to get an adapter for the oil connection and improvise for the electrical connection but it works just fine, my gauge is in the center position as it should be.
 

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Are you referring to the oil gauge on the dashboard. Is the reading supposed to go down to zero when you stop at a light and then go to the proper level when you are driving. I am a newbie....

Thank you, Linda
 

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Are you referring to the oil gauge on the dashboard. Is the reading supposed to go down to zero when you stop at a light and then go to the proper level when you are driving. I am a newbie....

Thank you, Linda
I can't remember if mine goes to zero or the bottom of the white area, I'll have a look next time I'm about in it.
 

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It should not go to zero. That—with a properly functioning gauge would be an indication of worn bearings. It will be significantly lower at idle, however, vs when you revving the motor.
 
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