i have a 92-95 jdm b16 swap in my 96 coupe. Im running a p30 ecu. I am not running a knock sensor, and i dont get any check engine codes for it. But on the other hand....i do get a code 21 (vtec selenoid) I was wondering if the knock sensor and vtec are related, or if me not running a knock sensor would cause me to not have vtec and to throw a vtec code?

 

Hmmm...

Double check your wiring and double check the code. Throwing either a knock sensor code, or a solenoid code will prevent the motor from switching to VTEC.

 

Do you have your vtec changed in anyway, for example a vafc? If it is changed a significant amount from the stock setting it will cause a vtec solenoid code. The ecu thinks the solenoid is malfunctioning and activating at a different rpm.