Thread: The ins and outs of the stock idle control system.

Is it just me, or does this seem to be missing from the VE engine?

The setup on the throttle body replaces that.

Yes, the wax actuator on the VE throttle body cracks the throttle body open when cold. When warm, the wax expands and closes the throttle body completely. This takes place of the cold idle valve.

Do you know how this is routed? I looked at my IM and it seems that this goes from an opening (non-vacuum) going into the IM 'passage' which then goes to this AAC and then to the IM..so in other words it looks like:

Intake piping -> Closed pathway through IM -> AAC -> IM

So I think the AAC simply lets air from the intake piping into the IM when the throttle is closed. It looks like the AAC connects between the two vacuum ports on the IM but I don't think that's accurate, I think the AAC only connects directly into the plenum once, not twice and the other end connects into the intake piping via a closed path inside the IM.

@gomba, you are correct. There is an aluminum passageway cast into the intake manifold that this device uses as part of the tract to the intake piping. This is a passageway completely separate from the intake plenum, even though they are part of the same casting. Depending on which intake manifold you have, there are a few of these passageways for air and (more often) coolant throughout.

Cool, answers my question! Also confirms I had the right idea.

I wonder why Nissan just didn't run a long hose directly from the AAC to the intake pipe and instead chose to use the manifold as a coupler between the two.

Does the pathway also feed the IACV?

It is possible that it also feeds the IACV, I haven't looked at a manifold close enough in a long while to remember. There are tons of sealed off passages in some of these manifolds.

I think my AICV is dead..I put it on my custom manifold and the car still can't stay running until the car is warm without cracking the throttle. I am missing the IACV though. Hopefully will have that re-incorporated soon.

@BenFenner : Is the operation of the AICV purely mechanical or does the connection back to the ECU control it somehow?? If you were to unplug it, would it still operate the same way?

Can you use the VE throttle body? it has a device that will crack the TB open for cold idle, and close it when warmed up.

@gomba, re-read the description above. It tells you exactly how it works.