NB idle control in Tunerstudio
 

I understand the NB idle controller needs to be set to 500Hz.

In Tunerstudio under PWM idle settings I believe I need to set the valve frequency as 30.5 x (this frequency).

I'd imagine to get it close to 500Hz that number would have to be 16?

The maximum Tunerstudio allows me to set is 8?
Should I be able to set this higher? The setting I originally had in there was 12, but when I changed it to 16 it automatically flipped to 8 and I haven't been able to set it back.

What do I need to do to stop the valve humming?

This is using the latest version of Tunerstudio on a DIYPNP.

A PWM multiplier Board is one way.
https://www.miataturbo.net/megasquirt-18/99-diypnp-1-5-build-comments-questions-48516/ (4th point in first post)
But I have botherered to tune my idle that well (needs some throttle while cold), it's not my DD and I have no AC or PS to care about.

You do need Jean's PWM board.

Dimitris

Thanks for the info. Mine idles fine without the IAC, I just want it to be more bulletproof to random loadings. I still have aircon in my car. Very hot in summer here. :)