check your wiring for vtec, if you had to add the wiring for the vtec pressure switch and the solenoid, check them, also on the solenoid, check the screen, could be gunked up.
also you said the check engine light comes on, first thing to do is the check that check engine light, see what the hell is going on, smarter to do that first, so that it could point you in the right direction, also for shits and giggles, check plugs and wires