i have a 97 asccord exr, 2.2 F22B1 SOHC. shortly after i bought it, the oil light came on. after checking the pressure with a gage at the sensor point, we determined the pump was likely bad. a few days ago we started in on replacing the pump.
when we removed the valve cover we found a ton of dried sludge over the rocker assembly, so picked up some engine flush for after the job.
next, we tried to remove the crank pulley (another story) but ran into the problem of not having the right tool. we decided that since we couldn't do that job until we got the right tool. that we'd try flushing the engine just in case the problem was being caused by the sludge. we drained the engine, filled it with fresh oil, a new filter and a bottle of quality engine flush. we ran it at idle (as per instructions) until it reached themerature, then drained the oil. next we filled it with fresh oil and a new filter and again brought it to temp. at start-up it ran 20psi @ idle and as high as 60psi @ 3000rpm, but as the oil warmed up, the idle pressure dropped to less than 10psi and would barely raise higher than 10psi even when rev'd. we drained the crankcase and inspected the main bearings, rod bearings etc for wear. we found nothing that indicated enough wear to cause low oil pressure.
it was looking at this point that it was the pump for sure, so we got our hands on the pulley-holding tool and went to work replacing the pump. when we were done, the cold idle pressure was 40psi and at 3000rpm we got more than 80psi. as the oil heated the idle pressure fell to 15psi, but 3000rpm would still bring it up to almost 80, so we figured we had the problem fixed. we put everything back together and checked the pressure again, and all was fine.
i live about 30 mins from the garage we used to do the job. on the way home from the garage, less than a mile from my house, the oil light came back on! we put the o.p. gage back on and found the oil pressure was dropping to 7psi at idle again.
after verifying there seemed to be no bearing damage and having replaced the pump, filter and oil (10w30), and doing the thorough flush, we are absolutely stumped. i have had a few people tell me 100% synthetic oil might cure the problem, but i am not convinced it will...i mean, the low pressure light came on for a reason.
other than switching to synthetic oil, does anyone have suggestions that might explain/cure this problem?

 

anyone?

 

I'll take that as a no.

 

That is hard to diagnose from just reading. Have you done a compression test? are there any noticable leaks that have developed? Has your clutch started slipping (rear main seal)? It seems like you have checked most everything so it is hard to tell you to do something you have already done you know.

 

sorry...i didn't mean to sound like an a$$hole.
there are no leaks anywhere. this car is super clean inside and outside. we didn't do a compession test due to the fact ther was no sign on smoke with the exhaust. that shouldn't effect oil pressure anyway.

i've decided it HAS to be a bad bearing somewhere, so i'm gonna start with the main/rod bearings first and work my way through head and finally balance shaft bearings if each replacement makes no change.

thanks for your patience and for giving me a place to vent