This may be of interest to some of you guys who've done the 00VI mod to your 4th gens:
http://forums.maxima.org/showthread....=1#post4260399

 

Yep, you are not supposed to supply vacuum to your VIAS, it doesnt need any sort of vacuum or anything connected at all, you could leave it alone and as long as teh electrical is connected it will open fine...

That's just, "takes in a breath" when it opens, but needs no vacuum as it has its own vacuum canister system built in... hard to explain, wheres Stephen Max... lol

 

The is a vacuum nipple on the front of the VIAS (as an integral part of the Vacuum Solenoid Switch (VSS)) that is designed to have a vacuum source hose attached to it. The power valve actuator depends upon vacuum to open the power valve.

 

Thats why mine opens with no vacuum connected to it ? o.O

 

The nipple on the front of the solenoid is not for vacuum... it supplies ambient air, from the intake ducting BEFORE the throttle body, to the power valve actuator. When the solenoid activates, it cuts off the ambient air and allows vacuum to pass to the power valve actuator. The vacuum comes from a tank located internally in the VIAS assembly/manifold.

 

Thank You..

 

Question: If the nipple on the front of the solenoid is not for vacuum... (as you say, it supplies ambient air), then where is the vacuum source for the internal tank in the VIAS assembly/manifold?
Point of Information: The Nissan FSM clearly shows on the Vacuum Hose Drawing (Page EC29) a line that draws vacuum from the smaller of the two, side-by-side vacuum nipples on the top, rear, middle of the manifold, which then supplies the vacuum to both the VIAS Control Solenoid Valve and the Fuel Damper.

 

I just set mine up with a Summit RPM switch and it is working fine without any vac source to it. With the vac source, it cause it stay open at all times.

 

That line does not actually go to the VIAS.. it's a little misleading the way the picture is drawn, as the air lines coming off the VIAS are not drawn far enough to see that they continue past the vacuum line you mention. That line does come down to the damper yes, but not to the VIAS. The vacuum source for the internal tank is the manifold itself. There is a small opening with a one-way valve leading from the manifold into the VIAS assembly. When the engine is running with high vacuum (at lower speeds), it sucks all the air out of the tank (for lack of a better way of putting it). At a certain point when it revs higher, and manifold pressure goes up, the one-way valve closes, thus keeping vacuum inside the tank, which then gets passed to the actuator when the solenoid opens. If you look at the overall engine control system diagram (previous page I think) it might make more sense.

 

Well, I just went out there with the electrical connector plugged into the VSS but not hooked up to any power source. The vacuum hose to the VSS was pulled off and plugged. With the engine running I touched the two leads to that VSS electrical plug to the battery terminals. Walah, that puppy avctuated! And again, and again and again (just to make sure it wasn't operating off of residual vacuum in the built-in vacuum reservoir).
Feathers Suck!!

 

So Do I need to hook up the nipplke to a vaccum or to the intake system?You guys got me confused lol, but sometimes doesnt take much.

 

Its best just to run a hose into your intake, NOT the manifold, into the intake tubing where theres no vacuum present. Just so it gets ambient, filtered air..

Glad you figured it out Curt.

 

hehehe.. well don't feel bad. The only reason I know the system so well is that when I did my swap I too was a bit mislead by the diagram and connected a vacuum hose only to notice the power valve was open all the time. So I pretty much had to take a good look and figure it out, which is why I know it now.

 

Curt, I believe I explained to you in PM where the VIAS gets its vacuum from. As DandyMax said, it's in the manifold. The one-way valve is the round black thing with the red stuff inside in this picture (towards the top of the manifold)-

 

That is interesting. I think I connected the vacum source to the VIAS too.... Need to take a good look at it.

Anyone have a CLEAR Picture of the actual VIAS plug?

 

If you connect vacuum to the VIAS it will open and stay open