This is an update on my efforts to find a way around a stuck-open AAV on my D-jetted B20E.
Following George Downs' lead, I pulled a K-jet AAV in a junkyard (I also pulled one from a D-jet, but it was, of course, stuck open too.) After cleaning the electric AAV out with PB Blaster and Carb Cleaner, and then giving it a drop of oil, I tested it on the battery and could see the slide valve close. When it looked totally closed, I tried to blow through it -- a very, very, tiny amount of air went through. Then I simply spliced it into the hose between the old AAV and the manifold/vacuum chamber nipple. I have a generic hose there with a generous loop in it to keep it from kinking. This allowed me to steady the thing by attaching it to the fuel rail with a zip-tie.
It did the trick. Engine runs initially at about 1500 rpm and, well before the radiator hose warms up, settles back into a nice 900 rpm idle.
George, I didn't have to put any sort of blockage in the hose -- maybe because this particular valve appears to be only about half open when cold, or maybe because it is working in conjunction with a partially functioning thermal valve. Whatever the reason, it's doing the job I needed it to do. When I come across another K-jet valve I'll check if it opens the same way.
Bob S.