Ever since I got the car, there has been an oil light at startup. It remains on for about 10 seconds, unless I rev the car (reving to about 3k makes it go off almost instantly). (SR20DET)

Followed with the light, I do get timing chain rattle, so it doesn't sound like a bad sender.

If the car has only sat for a very short while (less than a few minutes) the oil light doesn't come on at start. If it has sat for 15min or less the oil light goes off much sooner.

I have replaced the tensioner with the newer designreplaced the oil pickup gasketreplaced the oil pan with a greddynotched the pickup a-la s14 pickup

Ran at least a few different engine flushes, detergents, and oil weights to no avail.

I originally figured that $1000 or/so for a new long-block was no big deal, and would drive the motor until it blew since it probably was messed up already. However it has been since febuary of daily driving it with no issues arrising.

No bits of bearings in the oil pan, no metal shavings, no abnormal cam wear

Here is where it gets slightly strange, when replace the oil strainer gasket I noticed that the oil pump orrifice looked dry, along with the strainer tube itself. As if its not sucking up any oil.

However oil is definitley circulating, as it gets dirty and there is oil pressure after I rev the engine a bit.

So my only thoughts at this point are - somehow the oil pump is sucking oil from somewhere other than the pickup?

Or possibly there is a restricted passage right around the oil pressure sender and the timing chain tensioner (as they are right near each other).

Any idea's?

The only things I haven't checked obviously are the pump itself and the relief valve. However the removal of the subframe/lower pan makes me rather just swap the motor out for a known good one than go through the bother.

possibly the oil pump itself is dying, this happened to my ka also and after about 700 miles of driving(after bein OEM rebuilt, cept the oil pump) it started ticking real bad on the valves and then engine just died.it would start with the oil light on till i would rev it or till couple of mins, it would be normal after driving and turnin on 15 mins. i didn't think it was the oil pump until i revved to ~6k rpm's once and saw the oil light on, then another time revved to same 6k and oil light on, and then the valves started ticking, couple more miles to get home and the engine would run like crap and not rev past 3k rpms.

I have considered that, but it seems kinda odd.

The pumps are mechanical, and should be pretty bulletproof. In the absense of picking up crap and scoring the hell out of the gears, I don't see how it would fail.

And there is nothing in my pan/oil that seems like it would scorei t.

It also wouldn't explain why the oil pump pickup and inlet were dry? If it were just weak, it seems like it would suck up some oil even if it wasn't much?

Is there a seal or something between the oil pump and the pickup adapter that could be leaking? And its sucking oil from there instead of below the strainer?

unfortunatly, since it is mechanical, failure is almost inevitable. Friction and slight manufacturing impefections take their toll over time. Bearings fail and rotating parts fatigue, etc... Your right though, if it was weak, it would just pump less oil, but that is probably why your light is on, there is a minimium oil pressure your engine should have. IIRC the timing chain tensioner is operated by oil pressure, so that could be a clue.

but wouldn't it wear somewhat purportionaly to the rest of the engine?

The top end is definitley unscored and in good condition.

There are not that many miles on the engine itself, where oil pump failure seems likely due to normal wear and tear.

Weak oil pump is definitley possible, but from what I have observed doesn't seam to be the most likely? If that makes sense.

In theory it should wear proportionately, but there are different factors going on in each engine and manufactured parts are never truly exactly the same. You get lemons and things that fail early, then again you might get a better than average, like the one guy whos honda accord lasted 1,000,000 miles or whatever it was with no major problems. Just gathering from your posts it seems like the oil pump could be the problem, but that is by far not the only thing that could be wrong.

My 03 g35 does the same thing
oil light after car sitting after at least 20 mins but disappears quick
if i leave my car overnight it take about 5 to 6 sec to turn off
changed the oil 3 times no metals found
heres a video https://www.youtube.com/watch?v=-tQufOdO9TA

15 year old thread... on a different car with a different engine. Recommending you go to the z/g chassis or vq motor forum for help. You may have something in your oil pickup.