Okay so I'm having a problem with my vtec. It seems to be working whenever it wants to. I started having problems yesterday, I noticed that while I was driving and got to around 4000 rpm the intake was making a loud humming/vibrating noise and once I got to 5500 rpm then vtec kicked in and the noise went away. I never got back into vtec again nor did I go near 4000 rpm. So on my way to work I decided to get in vtec again to see what would happen, the noise still happened at 4000 rpm but this time no vtec. I got home started looking through to motor to see if anything looked out of the ordinary and nothing. I went to get fuel and once I left the gas station I got back into vtec and it kicked in again. I have a completely stock 93 H22A1, only thing done is a punched cat and fidanza 8lb flywheel. Oil levels are fine and I'm not getting any cels, could my problem be a air/fuel mixture problem?

 

Don't have any big experience with v-tec or anything but it may be your ecu module? or throttle body? or possibly hydraulic press? my 2cent.

 

change your oil. reset your ecu [take neg off batt] and try again, happened to me, oil levels were fine,vtec wouldnt work, changed my oil, all has been dandy since.

 

You might not have full oil pressure, whenever there is a slight drop in pressure the ECU will protect the engine by disabling VTEC.

 

ill do that first thing tmrw morning.

 

I'd have to check my OP. Waht's the pressure supposed to be at?