Dave,
I found out when I had a problem a couple of years ago, that the hot wire for
the Aux Air Regulator is connected to the injector hot wires, with a
connection hidden up inside the loom.
I ended up separating them and running a separate hot wire from the fuel pump
hot wire to the AAR, which gets turned on at the same time.
This hidden connection had me guessing for quite a while.
Mine is an '84 which may not be exactly the same as yours.

Comment is made just in case it could be relevant.

cheers,   Steve