Pressure Sensor / Free Boost Sensor?

[kycaveman]

OK, So I have removed my YCIS and plugged the ports, but what exactly does the sensor do that is has a vac line coming off of #1 (#2?) jug and runs up under the dash and hooks to the Pressure Sensor / Free Boost Sensor? I can't seem to find anything about it. Just wonder ing, and how does one test it?

[pegscraper]

That little thing reads the intake manifold vacuum and controls the part throttle spark advance, like the vacuum advance unit on the side of an old car distributor. Under part throttle, it will advance the spark to get better gas mileage. Under full throttle, it will retard the spark to prevent detonation.

 

I saw how to test one once somewhere, and I tested one, but I don't remember where I saw that or just how I did it. IIRC, It requires a VOM and a vacuum pump with a gauge.

[cliffno350]

the book say apply 12 volts and should have 2.5 volt out dont remember which pins are which but can look if ya need me to.