Auxiliary Air Valve question Options

[torakki]

This is on a '74 2.0. This car's been on and off the back burner for a number of years. (To many cars). It now runs very well, "Except", when it's cold, it idles perfect. As it warms, (about 2 minutes) the idle gets faster to about 1800 rpm. After a 15-to-20-minute drive, I shut it off. Restart a few minutes later and the idle is slow to wont idle fast enough to keep running. So, I'm checking the Auxiliary air valve (I took it apart) and when it's cold, it's open halfway. When it gets warm, it closes. Shouldn't it be opening when warm to let in more air to keep the idle speed up? In other words, lean out the mixture? I would think, when cold, it should be closed to richen up the fuel and warm, open to lean out.
Am I 180 degrees off?
Thanks for any input.

[emerygt350]

what a beauty.

Here is my suspicion. Your aar is working perfectly, it's the timing/advance/retard/weights.

The AAR is covering up the idle issue on the cold engine. As the aar stops pumping the idle up the car is retarded too much and your idle is therefore too low. I would first try just disconnecting the retard (and plugging the hose of course) to see if that makes a difference at idle. If it moves to where it should be, and you are not a picky person, just leave it.

If you are a picky person, like me, I would want it working correctly so I would immediately start looking to the timing. If the timing is where it should be (let's say 8 at 900rpm is good enough) with the retard disconnected, then you probably just need to adjust your idle air screw and possibly the ECU idle richness knob.

be aware that some early 74 had retard and advance (I believe) on the TB (2 ports or one port on the tb). Be sure your retard (the port facing the back of the car) is hooked to the retard on the can (they will have both but on a late 74 the advance side should just be lying disconnected). That should only have vacuum at idle and rapidly losing vacuum with opening the throttle. The retard on the can is the port facing the dizzy I believe. If you have that retard port hooked to the advance side of the can you would probably have the reverse issue with a high idle so that isn't it. If you have sticky plates in the dizzy you could end up timing the car a little randomly and afterward when the retard pulls it might be retarding too much. Good reason to be certain about that base timing if you are using the retard 'feature'.