Did you add a knock sensor to your LS block? Or does your AEM EMS bypass the need for that?

The LS block didn't come with a knock sensor in it, and the OEM ECU looks for a signal from that before it allows the VTEC to engage.

If the EMS overrides the need for a knock sensor, like the Apexi VAFC does, then is should just be a matter of hooking up the VTEC control wire to the Green/Yellow wire coming from the VTEC Solenoid.

Hope that helps.