Oil pressure?

[Jim Haseltine]

A few weeks back I had a problem with the oil pressure light in my 88 Ur-q
flickering on and off. At the time I put it down to a lower than normal oil
level and a long high-speed journey. Problem disappeared after I changed the
oil and filter. Then last night just as I arrived home the oil light flicked
on a couple of times. This morning everything was ok until I got about a
mile from work, then the light appeared again but went out when the car
slowed down. Kept appearing/disappearing very strangely, when the engine
slowed, when I hit a bump in the road, right turns, left turns but was
always out when the engine was idling. Oil level was ok and I couldn't see
anything wrong, a look into the cam cover showed that the cam had a coating
of oil so nothing was running dry.
Tonight's journey home was like a disco, the light was on and off all the
time, no pattern at all other than it was out at idle and out at 3000+ rpm.
When I got home I tested the sender and it failed all but one of the tests
(resistance when the engine was off) which was a pain because it was fitted
in January. Never throwing things away, I swapped in the old sender (which
passed more of the tests) and now I dont get the light.
The sender that failed is #035 919 561 A 0-5/1.8Bar and the old one which
I've refitted is #035 919 561 0-5/0.3Bar. Now I'm not too certain whats
happening here, it could well be that my engine is suffering low (<1.8 bar)
pressure but not low enough for the 0.3 bar to switch. I figure that I need
to hook up a pressure gauge directly to the engine and also to try another
1.8 bar sender. Luckily, there's a 1.8 sender on my parts cgt, so I can try
it this weekend.

If anybody knows anything else that I should check, feel free to let me
know.
BTW, the engine was rebuilt with new bearings, new head and a new oil pump
last year and has only been used since January, covering approx 3000 miles.

Regards,

Jim Haseltine