1986 XJ12 Sovereign.165 Km only on odometer. The original sender failed a few months ago and I replaced it with
an original unit with the markings. " (JDA PTR 1001/10/EC 700 kN/m2 )"
After failed attempts to break the seal on the original unit, we made a special tool that would allow a firm grip between the firewall and the sender and managed to remove the sender. Replaced both the sender and the oil light unit and it worked fine for about 10km distance. The gauge then stopped working although the oil light remained off.
I checked the oil pressure with a mechanical unit and although it registered very high, it showed good pressure. There were no oil leaks and the oil (synthetic) was spotless and up to the mark.
I replaced the sender with another new one which only lasted about 2 kms before it died. Pressure readings on both units was around 45psi after fitting.
I am reluctant to keep buying new units at around AUD $100 each unless I can determine why they are failing.
I replaced the oil gauge with a working unit but no change.
I had an auto electrician check the wiring and it was fine.
Any advice would be most welcome as I am looking to sell the Jag and naturally want everything to be in good working order.
Many thanks.
I’m not sure about this, but did the 86 use a voltage regulator behind the dash to run the instruments? From memory 8V or 10V? Perhaps the voltage regulator has failed supplying direct battery voltage to the sender and overheating it?
So far as I can see, the regulator wasn’t used from at least '89 onwards.
I suspect your problem is poor quality spare parts. Howvever, at the end of the day, the sender is just a variable resistor and it might be that the oil is leaking into the housing. I seem to recall a post from years ago where someone pulled it apart (what have you got to loose) and fixed one.
“I suspect your problem is poor quality spare parts. Howvever, at the end of the day, the sender is just a variable resistor and it might be that the oil is leaking into the housing. I seem to recall a post from years ago where someone pulled it apart (what have you got to loose) and fixed one”
It may not be directly relevant here but many years ago l did dismantle the sender on my series 1 xj12 and found bad contact between the sender itself and the spade connection on the outer casing. The internal connection between the two was made by way of a simple leaf spring on the underside of case contacting a small pad. I suspect the cause was in fact leaking oil contaminating the connection while no oil was evident on the exterior of the sender.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
5
I’m not sure about this, but did the 86 use a voltage regulator behind
the dash to run the instruments?
No, the instruments operate at system voltage. Supposedly some of the
early saloons used a voltage regulator.