Check your oil level. low oil will not allow you to engage VTEC,
Check your ECT sensor as No or a Damaged ECT(coolent temp) sensor will also not allow you to run VTEC
Check all your grounds!!! check them very very good.
Make sure you have a working VSS(speed sensor) as VTEC wont work without 1..
and last, test the VTEC solenoid. Run a wire from the positive batt terminal and touch the single wire that connects to your VTEC solenoid, it should click when applying power to it and if you have the motor running it will make the motor kinda bogg down. If you get this Bogg then VTEC is working. if not and the solenoid doesnt clich then you need a new 1.
If you pass all these tests with flying colors then you either have a clogged VTEC oil passage, or your ECU is damaged
VTEC needs these signals to work:
VSS(speed sensor)
VTP(Vtec pressure sensor) oil pressure
ECT(coolent temp sensor)
VTEC ECU
BTW what ECU is in that car?? some people swap motors and 4get to swap ECU's
If so I have 1 lay'n around you can have. LMK