MicroSquirt.com read only forum (Jan.15,2018)

Couple of additional notes:

The valve responds best at approx 120hz
Too high a frequency and the valve never seats under vacuum after being opened
Too low a frequency and the valve loses granularity (e.g., 31% = 700rpm idle, 32% = 1000rpm idle)
Adapting this to a manifold that had no IAC valve ...

I hooked the valve up to the intake manifold and sure enough, the manifold vacuum was required to close the valve, at which point varying PWM has the desired effect of actuating the valve. Phew!

So the lesson is: A PWM IAC valve from a Crown Vic requires vacuum to seat, and thus requires vacuum to ...

I found an old post on this forum that suggests this valve must have vacuum being pulled through it to actually close? Is that possible? Bugger.... didn't think of that.

Wonder if my vacuum cleaner can suck hard enough for bench test...

EDIT: Below is my original post where I could not get it to work while bench testing. Please see the rest of the thread for what I was doing wrong.

Hi,

I picked up a Borg Warner IAC valve (#22971, 2 wire, for a Crown Vic ) to play around with on my DIYPNP. So far I am unable to get the valve to do ...