With the electrical signal plug disconnected (just to make sure it wasn't contributing to the problem), as soon as the engine starts the power valve actuates (regardless of RPM). As soon as the engine's shut off, it closes.
Somehow/somewhere within the VIAS or the vacuum solenoid switch (VSS) the actuator is getting a straight shot of vacuum as soon as the engine starts, and continues/holds it until the engine's shut off.
Anyone have a clue??

 

Ah wait, I PM'ed you a reply stating what I thought the problem could be, but I didn't realize you had visual confirmation that it is activating/deactivating.

I'd imagine the vacuum solenoid is stuck open or something. It can be removed--a little prying on the front cover where the atmospheric vent ports for the solenoids go through, and it'll pop off, giving you the ability to remove them-- http://spirilis.net/gallery/view_pho...wn&id=dsc01153 (pic with the VIAS control solenoid removed, but the Swirl Control solenoid still intact)

Might want to try removing the solenoid and probing the contacts with +12VDC and check if you can hear it click/see anything moving inside.

 

Thanx for the suggestion. That'll be my next step, as I do clearly hear the click when I apply the 12V, but don't know if anything inside is moving or not.
BTW, do you know if the Power Valve VSS and the Swirl Valve VSS are interchangable? If so, I may be able to find someone who's installed an 00VI with both solenoid switches onto a 4th gen (as I did), but is not using the 5th gen lower IM with the swirl valve, and might be willing to sell me the unused VSS.

 

if youre the tinkering type, you might try taking it apart and checking why the plunger is stuck/leaking. and possibly fixing it.

 

Well, I've taken it apart, and the vacuum solenoid switch seems to function correctly when 12V power is applied.
Can anyone tell me, reguarding the normal functioning in the 5th gen Max, if the ECU provides the ground thus "completing" the citcuit when the threshold RPM is reached, or does it break the continuity. In other words, below the threshold RPM is the vacuum solenoid switch normally energized or not?

 

normally not energized and normally closed IIRC.

you say it functions correctly, but didnt you find is was leaking

 

No, there was no leakage. And BTW, excuse my ignorance, but what does IIRC mean?

 

IIRC = If I Recall Correctly

 

Well, I've just checked out another 00VI (uninstalled), and a simple vacuum (i.e., suck) on the power valve VSS nipple opens that puppy right up. That's without any electrical signal to the VSS. Simply put, with no electrical signal to the VSS, and as soon as the engine is started the power valve will open right up. Hard to believe, but anyone have corroborating or contradictory evidence???

 

your VIAS does not need a vacuum line.

 

http://forums.maxima.org/showthread....=1#post4262128