Help! 91 Prelude Oil light is coming on.

I have a 91 Prelude B21A1 which I auto-X regularly. Now after exiting
the interstate idling at the light I noticed the oil light blinking.
Idle seems a little low. Light goes out if raise idle to
1000-1100rpm. If i don't, ecu makes it start flashing & have to turn
ignition off/on to reset it.

Are the engines days numbered? Can someone explain in detail the
oiling system. Is it likely the main crank bearing are where the
pressure is being lost? Can an external oil pump be installed in the
interim til an engine swap?

 

It would be best to measure the oil pressure to determine if there's an
actual problem with the engine or just an electrical problem.

Eric

 

If it's not electrical, check the oil intake in the oil pan. I don't know if
the '91 prelude has a screen on the oil intake, but my Civic does, and so does
every Civic from 84 to 91 (as far as I know, I don't know anything else..

Anyways, I Was having a problem with my car like that, and it was solved by
cleaning out the oil intake screen (not a big job), and then doing seeing if it
works..

 

I agree with Eric--the oil pressure needs to be checked. If you don't know
how to do it, take the car to your favorite mechanic and have him do it
for you. Also, do a compression check on each of the cylinders. It's the
best way to know whether your engine is in great shape or poor shape.

 

The way I'm running it at auto-x & a recent track day, I'm very sure
its an oil pressure loss problem. I recently had the oil pan off and
noticed a dozen or so 1-2mm non-magnetic metal flakes which I've been
told could've come from the main crank bearings. Does this sound
right? Is that loss of metal where I'm likely loosing oil pressure?
The oil pump can't really go bad, right? Although I don't really know
where it is. How is it connected to the internals?

Almost forgot, at that track day event, I ran the 1st 20min session
very strong & hard keeping up with the 4th & 5th gen ludes. Then
notices temp guage maxed at cool down lap. Didn't have heater blowing
for additional cooling. As soon as I turned it on, temp came down &
all seemed OK.
In 3rd session, downshifted to 2nd for accel out of hairpin and
noticed a serious lack of pull so I let up and idle wanted to drop to
500 and oil light flickered. So went to pit which was right there.
After short time restarted and idle seemed normal at 800.

Drove the 300 miles back home no problem. But oil light at every idle
now. How long before it seizes up?

 

won't sieze, but will make a hideous knocking noise when the bearings go.

the flakes you mention /do/ sound like bearings. and this fits with
your low oil pressure because when the bearings are shot, they do not
seal against the crank & the oil leaks. i suggest you stop driving this
asap and strip this crank for inspection. if you're lucky, you might be
able to get away with just replacing the bearings, but i think it more
likely you'll need it reground.

what you do from here depends on how much money you want to spend.
cheapest way out is pick up another stock engine and swap. a better
solution would be to rebuild your old engine, but to do it well takes
$$$$'s. if you're competing, look at it as a great opportunity to
lighten the crank, con-rods, balance pistons, etc.