Alright its a 1994 prelude si pretty much stock except for I,H,E I noticed vtec wasn't engaging so I popped the hood and noticed one of the engine ground wires was disconnected I hooked it back up and vtec still did not work does anyone know what it could be? All insight welcome. Thanks

 

if your car is a prelude si are you saying you swapped in an h22 and the h22 isn't engaging vtec then did you know you must wire in vtec for it to work?

if this is not the case i'm sure more information on your part would be helpful to other so they could help you.

 

The car is an original Si it came with a usdm h22 its never been swapped the only mods are intake headers and exhaust. The car has like 110k on it. Vtec has always worked fine, could it be that the solenoid locked up? Or what would be some good ways to diagnose it?

 

when was your oil change? and pull off the solenoid and clean it

 

Ok so after checking the oil level and finding that it was low we put 3/4 of a quart of oil then vtec was working perfect again. I never knew that low oil would cause vtec not to engage.