Lude Generation

I recently just bought a 1994 prelude BB4 and I found that when I drive the car into vtec the engine oil light comes on but as soon as I turn the engine off and on again it goes off.The oil level is perfect aswell.

any ideas whats going on? I recently bought the car from an elderly gent who owned it since it was imported and I would imagen the car has never even been revved high enough for vtec.

Strange one... That oil light is driven by oil pressure.

Can only assume that when the vtec spool valve is activated, oil pressure is dropping sufficiently to cause low oil pressure.
That would either be because oil pressure in the engine is low/marginal anyway (and the extra load causes it to just drop below the threshold) or because there is a leak/massive wear in the valve gear operated by the vtec oilways (meaning massive run by of oil, dropping pressure in the whole system).

Are there any visible oil leaks on the gearbox side of the engine?

If not, suggest you get the basic oil pressure on the engine tested asap, as a starting point. A decent garage should be able to do that for you. Description of how to (and what results you should get) should be in the service manual, which you can download for free via a link on the forum (if you haven't already).

Either way... Don't for God's sake run it in the vtec at the moment!



Edit: another option (unlikely?) is that the wrong viscosity oil is in the engine, or the wrong oil filter. Do you know what has been fitted in those regards?

assuming there are no oil leaks in the obvious places then it could just be a bit of gunk has built up in the mesh strainer and blocked the spool valve (vtec solenoid)
you can take this off and clean it up very easily - worth checking

That should just mean vtec doesn't engage and if anything, oil pressure should drop less than with the filter clear though? (less oil flow is possible into the vtec oilways therefore less loss from the main oil feed system) Unless I'm remembering the oil system schematic incorrectly...

Like you say it's an easy check though, so might as well.

If there's any nasty metal crap in there, it will tell it's own story...

I was going to suggest if the oil pressure was low enough to fire up the oil light, then surely vtec wouldn't kick in yo?

there is oil on the sump and there is signs of oil on the block but i think the gearbox looks clean.I was told the oil was topped up but it looks like it needs changed as its black.I just done an 8 hour journey home in the car and it drives very good and it did not seem to use any oil either.its only on 160KM so its quite low milage for a H22a.

I will change the oil and filter and see if that's helps.what oil would you suggest for this type of engine?

If it's just done an 8hr journey without going bang or using any oil then it's highly unlikely to be a genuine lack of pressure to my mind...

try a new oil pressure switch

thanks for the reply's.if the new oil and filter does not work I ll look into the new oil pressure switch and I ll check the vtec solenoid too,fingers crossed!

Or maybe someone make vtec light of it as (IMHO) oil pressure light itself is prety much useless in prelude. Seen more crazy things in the past. Still worth checking
Is this light coming on just after you turn the ignition to position II but not start the engine yet? Should stay on until you will start the engine.