1995 4.0 AJ16 XJS Oil pressure sensor

[XJSDave]

Hi People, Cheer up, spring is next on the horizon. Having just replaced the fuel injectors which improved the tick over smoothness and starting although I didn't have an issue with starting, now takes half a turn instead of one and a half turns to burst into life.
Changing the injectors has made a positive difference but I have now ordered, on line seems the only place available, a fuel injection pressure testing kit to check the pump on tick over, should be 35psi - 45psi.
Also an occasional flickering of the oil gauge I've decided to change the oil pressure sender on the engine as a initial attempt to sort it but can't seem to see where mounted on the engine, I suspect its beneath the oil filter, can anybody help ?
PS. My boot lights are not working, fuse not in the place indicated in the hand book R/H fuse box ( drivers right leg) No 11, 10 amp. Anyone know where the switch is that operate the lights so I can test for power ?
Many Thanks and
Regards XJS Dave

[ptjs1]

Dave,

As you'll probably know, there is an oil pressure switch and an oil pressure transducer. They are situated next to each other. The switch merely controls the low oil pressure light. The transducer controls the pressure gauge reading.

What you need to recognise is that if you buy a new transducer from Jaguar, you will not end up with a variable gauge reading based on the actual oil pressure in your car.

Jaguar received lots of negative comment from US owners in the 90s where owners were concerned at the oil pressure reading dropping at certain times (as indeed it should!).

Therefore, they introduced a replacement transducer which acted to force the gauge reading to sit at a midway position at all pressures unless the pressure dropped almost to zero. US owners were apparently happy with that. The part number remained the same and from that point, only the "fixed pressure" transducer has been sold by Jaguar. Me? I've stuck with one of the original transducers as I prefer to know what's really happening in my engine.

It is still possible to buy a proper variable transducer. I THINK that Beck Arnley in the US sell a suitable unit.

Good luck with whatever you decide.

Cheers

Paul

[XJSDave]

Thanks Paul, very interesting reply, l’m not that bothered about the oil gauge flickering now and again, didn’t know about the transducer and might try justxjs to see if Andy can rob one off an old engine otherwise it’s live and let live. Just finished the 3 stage process of polishing the car with Meguiars products, compound, polish and then wax , the results are very good and glass like finish, kits on sale at Halfords £35. Thanks again for your reply. Dave

[ng4xjs]

Help - I've got a faulty/leaky oil pressure switch sensor (oil warning light on most of the time etc.) Replacement received and then, how on earth do you get the old one out short of destroying it in situ. Looks like oil filter and various bottom hose pipes, those around throttle body need to be removed. I thought this was going to be a 10 minute job, sadly not.

Nick
1994 AJ16

[poprivet]

Old thread revival. My oil pressure sender has failed, gauge reads zero. earthing the sender wire it reads max so not the gauge. Oil pressure light works as intended.

As the new senders don't really indicate pressure is there any reason to spend £60ish on a new one? The warning lamp is more visible in case of failure, although by the time it lights I guess its too late anyway. I had a look at Beck Arnley but can't get a price without signing up to an account, I dont want to do that as I get enough spam mail as it is.

I can see an issue if the car was ever up for sale as it would put off buyers if they notice no indicated oil pressure. What would you do?

[davidr]

Hi Pop - my ethos is that everything on the car has to work whatever it is so I would change it. As you say, by the time the red light comes on there’s a good chance the damage is already done

[ptjs1]

Pop,

You know that you won't be happy until you've fitted a proper variable sender!

It's pretty easy to find a x-ref list of all the different ones that will fit. My memory is that people reported that the Beck Arnley equivalent was a proper variable sender.

Cheers

Paul

[poprivet]

A varible sensor has been sourced and fitted!

I am putting a YouTube video together explaining the testing and fitting process in general, but to assist others, here is some additional information. The same sensor has been fitted to the V12 and (old) XK engines so will be of interest to owners there as well.

Thankyou Paul for the Beck Arnley suggestion. I didnt get far with their website but research got me to Amazon 'Beck-Arnley-201-1505-Pressure-Switch' £33.46 Ideal and a good price.

However, some more research on part numbers turned up https://apaindustries.com/parts/5250 which led to Amazon 'B0066SKUFU' £29.08 which seemed identical but at a lower price.

I took a gamble and ordered it. It took over a week to arrive as I have a suspicion it came from USA? Here is the box:

A couple of notes: The old one had 17mm hex and the new one needed a thin 11/16inch angled spanner. No copper washer was sent with the new one and is a different size to the old one.

When the video is released I will post a link here and it will show why I know this is a variable resistance unit and not a switch.