CRX: vtec not working...

[DiabloGT160]

i think i have a problem with my v-tec, its not working so i hear from friends. ive never had anybody with a vtec honda that i could ride in thier car to hear it so i wouldnt know. the engine is a d16z6, or SOHC 1.6L v-tec from prolly a 94 del sol or something, i dont know because i bought the car how it is. the guy said that he never had the cpu changed(its a '90 crx), and that it should be changed because its running rich. my question is that if i change the cpu, what car should i take it out of or what company will sell them? i thank everybody for thier input--steve