Evening all. Can anybody recommend a good jag independent in the Worcester area? I need a compression test. Low oil pressure fluctuating 0- half way. Increases from 0 up to half way under acceleration. Sometimes sits happily at half way on idle. No performance issues but really hesitant to drive until diagnosis. Dealer always asks a little too much just to pop the bonnet. I’ve been told that the pressure sensor sometimes gives out and is the first port of call. XK8 - 80,000 on replacement engine (original was nikasil).

 

Sometimes reads normal, but can fluctuate wildly. If your oil pressure indication fluctuates that much, I'd guess that it's an indication problem. I used to troubleshoot this kind of problem on airplanes for a living and I can't remember an instance when fluctuating pressure indications wasn't an indication problem. Then it's just a matter of whether it's the transmitter or the gauge.
I'm not sure why you'd want to do a compression check for this problem, but a compression check is easy to do yourself.
Remove the spark plugs, pull the fuse for the fuel pump, and screw the hose for the tester into the spark plug holes one at a time. All readings should be within 25% of each other.

 

The pressure sensor is near the oil filter. Disconnect and clean the plug with electronic cleaner.

 

As per the electrical manual, this is just a switch, as in on/off.

 

Correct. The computer is programmed to place the needle midscale when the pressure is adequate (greater than about around 8 PSI) as sensed by the low pressure switch and at 0 when it is not.

Normal oil pressure can vary on this vehicle from about 8 PSI to 75 PSI, where it is limited.

You most likely have a bad switch or loose connection OR as is common on the older XK8s/Rs, a clogged oil sump screen from bit of plastic than have broken off the plastic chain tensions and guides. Treat a clogged sump as a warning to get those timing components replaced before the engine damages itself.

 

Thanks for the helpful replies. I guess I just want to check that there is no actual issue re. compression and potential engine damage......

 

Would this be:

1. Worcester - Wisconsin, US
2. Worcester - Vermont, US
3. Worcester - Pennsylvania, US
4. Worcester - New York, US
5. Worcester - Missouri, US
6. Worcester - Massachusetts, US
7. Worcester - Western Cape, South Africa
8. Worcester - Limpopo, South Africa
9. Worcester - Saint Catherine, Jamaica
10. Worcester - Worcestershire, England

This is an international forum. We don't ask members for much in the way of personal information and what we do ask is only to improve the accuracy of advice given in replies:

1. vehicle Model and Year in forum signatures - specifications change throughout the manufacturing cycle
2. Location - specifications vary across World markets

Graham

 

There is only one Worcester. The Faithful City. ;-)

 

I think this cryptic answer refers to Worcester in the UK.
You really are going out of your way to make it difficult to help you.

 

Read my PM.

Graham

 

Jaguar gave us an idiot light disguised as a gauge? Oh, the humanity!