I swapped a D15B7 into my brother's 93 Civic CX. Only thing not done is converting the O2 sensor from 1 wire to 4 wire. Anyways, before we took out the old motor, the A/C worked fine. Now, it doesn't come on anymore(pulley clutch not engaging/getting power). Could this be an ECU issue(Has a P06 in it right now, but P05 was stock)? Also, there's a loud, high-pitch whining coming from the intake. I'm thinking it's probably just because of the bore difference(ie air going over a sharp corner). Anyone else have this issue? Thanks!