Intermittent oil pressure

[RayPrichard]

Saturday 13th Feb, checked the oil on 1995 4ltr Sovereign & topped-up. (Maybe a half litre too much ?). Sunday started car, normal pressure, drove 20 miles suddenly no pressure registering & warning light on. As I stared at the gauge it went straight from 0 to Normal (mid gauge) & light went out, but only for 10 seconds. Drove .5 miles home (0 pressure). Same later. Today (Mon) checked oil level (a bit over max) started car & gauge went to mid point+. Pulled off drive & zero pressure, light on. Gauge needle does move to the start point when the ignition is first switched-on but not currently rising further.
Car had lain idle for 15months but has now done1,000 miles since Nov. Service history unknown, oil looks a bit dark !
Aside ? Seems to be intermittently ignoring seat setting (crushed knees) & bulb warning light on with brakelights or side lights but all bulbs okay. Any suggestions ? (My first ever posting).
Ray.

[alec2824]

The oil pressure light and gauge are a common source of problem. I suggest you look at the wiring from the engine and the sender in the side of the block. Clean the connection and replace the sender if necessary! I very much doubt that you have an oil pressure problem,.

[RayPrichard]

Thanks, all I now need to do is to find the sender on the side of the block !

[davidr]

You may find that there's a link lead between the connector and the sender. This has a couple of electronic units in it and given its position exposed to both engine heat and road spray may have gone haywire. It's purpose is, I believe, to moderate the signal between the sender and the gauge so it doesn't fluctuate too wildly.
I only say that because my Celebration XJS has the same AJ16 engine and this was a problem for me until I replaced it.
Hope that helps

[RayPrichard]

Thanks, as soon as it stops raining & I'm well enough to venture out I'll 'have a fiddle.'