and btw if you can hear it, than i think it's almost def not the solenoid because if it were engaging than the solenoid would be fine, if it were bad i'm assuming it wouldnt engage at all.
1: Oil level, it has got to be FULL. I'm talking at the upper mark on the dipstick.
2: Solenoid, Ok this is a 2 part fix.
A: Take a wire (any wire) disconnect the grey plug on the vtec solenoid and
touch the wire to the pos. battery terminal and the solenoid side of the grey
1 pin connector. there should be an audible click from the solenoid.
B: If A checks out, remove the solenoid and clean the filter screen. (self
explanatory)
3: Speed, the car must be going over 10 mph so the Speedo must be working. That
means the VSS has to be working. Vtec is temperamental isn't it?
4: More oil, check the oil pan. If its dented POUND IT OUT! This is why mine
wasn't working. The pan was dented in far enough to hit the oil
pickup for the
pump to cause a low-pressure situation in the head, no pressure no VTEC plus
eventually no
engine.
5: ECU Swap out to another ECU that you KNOW Vtec works on.
6: Car must be at I believe its 80 degrees or higher so let car get to a normal
operating temperature.
7: If none of the above work, you might want to pull the solenoid off the head, remove the solenoids filter and verify the piston moves freely.
That is the basic troubleshooting procedures for it. If I missed anything or got anything wrong, let me know and I will change the info.
If you go through all this and it still doesn't work its oil pressure (the pump) or wiring related. So check all the
wires for Vtec.
^^^ from jdmu.com