i have a 1992 civic hatch si. its is a ls vtec. sometime vtec kicks in and sometimes it doesnt. yes i know i need to let oil warm up. oil level is always good. i always let car warm up. yes speedometer works. no check engine light. yes i have cleaned vtec solenoid. yes vtec is wired right. and i am running a stock p28 ecu, yes i have tried other ecu's. so basically sometimes vtec engages and sometimes it doesnt. it is a ls block with gsr head if anyone needs to know. what should i do what should i look for? what could the problem be?
any help will greatly be appreciated. but when vtec does engage it screams loud haha.

 

anything?

 

Check your oil pressure..

 

I had this problem once. It turned out my radiator was too big and the car was too cold while driving, but at idle it was normal. Hope it helps

 

any other tips?

 

have you tried making more oil pressure?

 

what you do is you pull the oil pan off you'll find an allen key nut by the oil pickup. there is the oil pressure spring. undo the nut and shim where the spring sits with a washer .025-.030 of an inch. you might have to make one it easy. it will double the oil pressure from 50psi to 100psi at 6500-7000 rpm. make sure you got a oil pressure gauge. it will not hurt. i've ran it like that all last season (oval track) i run my civic at 7 grand all night long in 2nd gear 54.782 mph hope it helps