I didn't yet fully understand the theory of operation with the PAIR. And because I did not understand the processes involved with open/close of the PAIR, and misread the first test, I misdiagnosed the PAIR as another vacuum leak. I believe I understand now.The big question is why? The systems you are focused on are not your problem, leave them alone until you fix what's wrong then do as you wish.
The aft vacuum port supplies vacuum to the PAIR Solenoid which is closed during acceleration. During acceleration, the Solenoid is opened and a vacuum is pulled atop of the PAIR valve. What confused me is why a second vacuum line that T's into the PAIR system is attached to the intake breather on the lower aft left side of the filter box. When the Solenoid is open, how is vacuum able to reach the PAIR valve when the hose attached to the filter box is an open port? That's what confused me; in fact I am still confused. You would think that there would be a check-valve there to prevent vacuum leak during PAIR operation. Refer to the picture to see what I'm talking about.
Now I understand that when the PAIR solenoid is closed (cuts off vacuum), the PAIR valve must move to the open position and is relaxed (I assume by an internal spring) which requires the vacuum previously applied to the top of the valve has to have a way of escaping, hence the reason for the 2nd hose attached to the filter box. So I'm assuming that the vacuum pressure must be strong enough post Solenoid valve that it is able to close the PAIR valve even while vacuum pressure is leaking from the 2nd host attached to the filter box. Or is that hose plugged by a blocked port on the box? This is why I was thinking that a vacuum leak existed on the PAIR system.
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