Maybe I haven't found the right section of the FSM but it just says it's driven by the ECU and shows it as a solenoid. Doesn't specify if it's on/off or PWM or what. Also if PWM what is the base frequency. I'm working on my Fueltech base map and trying to figure out what to do about the BAC valve. It has an option for idle control using a PWM device. Sorry for the possibly wrong section but searching the engine management section didn't help much other than I did find the ISC valve on the FD is PWM and base Freq. is 244Hz. Thanks.

 

I guess I didn't look hard enough. Google found this old thread. BAC operating freq - RX7Club.com - Mazda RX7 Forum

Sounds like it is PWM base freq. 244Hz.

 

and the starting pulse width is about 38%. ideally the ecu outputs 38% and the engine is at 750rpm, if not it'll start adjusting. the valve gets really non linear at low duty cycle, like a fuel injector but worse.

 

Thanks. I'll go in and take another look at it and see if there is somewhere to adjust pulse width. I set up the idle actuator as PWM and 244Hz.

 

I ended up measuring one on someone's bone stock FC. Its somewhere in another thread - its 125Hz.