Suspect AAR valve no good, so I have a question: Is the power source that heats the air on start up to activate the valve 6 volt or 12 volt or something else so I can test the valve on the bench? Thanks for your help.

12V, same as the car.

The supplying circuit is hot when the fuel pump circuit is energized. - GA

Edit "Heats up the air"? The air is not heated, the valve simply opens to create a controlled vacuum leak into the plenum to raise the RPM. 12 volts closes the valve - thus the vacuum leak - and holds it closed during normal operation.

12 volts while the car is running are supplied, and also engine heat, both close it. you can usually free the door with wd40. If not we rebuild them

Thank you, Greg!

Thank you, Dr. 914!

Dont know if this will work for you, but when I suspected my AAR was not working on my '73 1.7, Brad Meyeur suggested to me to soak the inside with PB Blaster or similar, let it soak overnite, and heat up the top part with a propsne torch. I had this thing almost red hot, but you could hear/feel the spring release inside. Sprayed it down again after it cooled. Been working ever since.
EJP914

If the wire is still in good shape and the heating element works, here’s how I restored my AAR…

https://youtu.be/cBdjLrxvBIM?si=wkkbQva7OqAFH58f

Where does the AAR lead typically connect? Is there any reason I can't get the 12V from the No. 15 side of the ignition coil?

The downstream side of the fuel pump circuit, parallel (or maybe connected to?) the ECU circuit T12-12 (hot when fuel pump relay is energized). It's a 0.75mm supply wire.


It's a higher-amp circuit, running a bimetallic element. That answer depends on if you think the coil circuit can handle the extra load...all the time. That circuit is fused on S9. - GA

The AAR power lead is in the ignition wiring harness (also known as the engine wiring harness). It goes to the relay board, where it taps into the fuel pump circuit. The AAR is powered any time the fuel pump is running.

--DD

So...is the AAR valve necessary or is it only needed for cold starts?

The latter. A properly-working AAR will be fully closed and ineffective after 5 or so minutes (or less).

When I was still running full-up D-Jet (I'm now using Microsquirt with the D-Jet induction, see sig) I actually removed my non-operational AAR, plugged the ports, and simply tickled the throttle for a minute or so before I pulled out of the driveway. - GA

The function of the AAR is to make sure the cold idle isn't too low for the engine to consistently run. Usually it results in a slightly high cold idle RPM, which drops to normal as the engine warms up.

The engine will run fine without it, but the engine may not idle when it is cold.

--DD