Auxiliary Air Regulator (AAR) Repair
One source of vacuum leaks is the AAR (p/n 022906045). Mine was
full open all the time resulting in high idle when warm. When the
vacuum hose going to the air filter boot was removed a vacuum could be
felt even after the engine was fully warmed up. 12 VDC power to
the red wire was verified and the resistance from the red wire to
ground was infinite indicating a break in the circuit. I read Paul Anders D-Jet site and followed the instructions there on how to repair. It worked!
Tools and Materials:
Dremel Cut-off Wheel,
Drill, Punch, Pliers, Soldering Iron
Wirewound Power Resistors 5 watt, 5 ohm Digikey PPC5D5.0CT-ND, qty 2
Heat Shrink,
Female Spade Connector, Solid Wire, JB Weld, High-Temp Engine Paint (optional)
Procedure:
Step 1 - Remove lip of can with dremel cut-off wheel. Mark location of outlet on side of can for later reference.
Step 2 - Pull out valve and bimetallic spring. Mine had a broken
coil wire between the ceramic adhesive blob and the positive terminal.
Mark location of spring set screw before removing. Clean
inside of valve with degreaser and work valve back and forth until it
operates smoothly. Replace spring and set screw.
Step 3 -- Drill out the brass terminal rivets and bottom center rivet
to remove ceramic base. Use punch and pliers to aid removal.
Discard base.
Step 4 -- Check continuity of red wire and ensure it's not shorted to
base. Install new bottom strain relief using heat shrink.
Insulate exposed red wire inside can with heat shrink.
Re-crimp and solder new female spade connector on end of red wire.
Step 5 -- Prepare power resistors. Soldier two 5 watt, 5 ohm wirewound power resistors (Digikey PPC5D5.0CT-ND)
in series and add a bare piece of solid wire to one side for connection
to the negative post. Preform the ends for wrapping around the
terminal posts. Bend the joint between the resistors up so as to
not short on the case. NOTE: Paul
Anders site says Dave Darling uses 3 resistors, but when I used 3, the
resistors did not get hot enough to close the valve. Reducing the
resistance by using 2 resistors increased the heat dissipation to close
the valve.
Step 6 -- Apply JB Weld to the base, seat resistors in the JB and soldier the ends to the terminal posts.
Step 7 -- Apply bead of JB Weld to rim of can. Install valve with
outlet aligned with reference mark. Clamp valve to can and let
cure. You can test by applying 12VDC to red wire and grounding
base and accelerate cure! Be carefully, the can will get 200+ F.
Blow through the port to verify it closes in about 10 minutes.
Step 8 -- Wire brush outside and coat with high-temp paint leaving screw holes bare for ground.
Step 9 -- Reinstall with new branch vacuum elbow (AutoAtlanta.com
p/n 022133083) and 12mm vacuum hose (p/n N203741). Connect red
wire and screw base down for ground. Start engine and verify no
suction through inlet (top port) after about 10 minutes. Now when
your engine is cold, extra air will bypass the throttle plate through
the AAR for a higher idle until the resistors heat the bimetallic
spring enough to close the valve and resume normal idle with a warmed
up engine.
