I was wondering this bc my speedo doesnt work anymore and Im working on putting a B16A from a 88-91 SIR I into my rex. Will this cause the VTEC to not engage?

 

yes, if your using a pr3/pwo ecu it looks at several inputs to decide if its "safe" to allow vtec to engage, and vss ( vehicle speed sensor) driven by the speedo is one of the inputs it looks for, if your going to run like a pm6 with a v-afc then you dont gotta worry about anything except a wire from the vtec solenoid to the vafc

 

I didnt know I could keep using my PM6 and the VAFC with the B16

 

as long as you tune it. if you have the pr3/pw0, then go for it. otherwise, either chip the pm6 or get the vafc tuned.

 

alright cool, thanks alot