Aux Air Valve - Idle
 

Hey Hkp7 - How did your High Idle issue turn out ? Someone else may have already mentioned that there are times where the Aux Air Valve internal shutter can simply be sticking. This can visually be checked by looking through the hose connections. When the AAV is cold the internal shutter would be (at least partially) open - once warm (power applied to the heater pins) you should not be able to see through the hose ports.

What is nice about the AAV is that they can easily be disassembled for cleaning and then pop-riveted back together. Other than a sticking shutter, the only problem is usually a defective heater element. I think the 30 - 40 ohm resistance for the heating coil is the correct reading.

Good Luck,
Michael

Well, tonight I am going to switch the aux air regulator with the one that just came in the mail just to prove it doesent work either and probably going to mail both of them back to where I bought them and use my original until I figure something out. Any Electronics people out there, I thought about making my own heating element out of some type of resistor or resistance wire so it actually heats up when 12 volts are applied. I am thinking if three in a row are reading .01 which is almost a dead short, maybe used isnt the way to go and then again this part is no longer available. I disassembled my original and found the coil of wire that wraps the arm and I plan to completly disassemble it and replace the heating element some how. Just got new tires today along with alignment that was done on a newer machine. They did not have to raise the vehicle from its wheels like most alignment racks do. I am a bit curious about ride height though. What the readings are supposed to be and where to measure.

the WSM has pictures of where the ride heights are taken from and the specs

Aux Air Valve -
 

This past weekend I helped a friend with a similar High Idle problem. After the Aux Air Valve tested fine - we turned to a search for air leaks. It turned out to be a binding throttle cable. The owner had over lubricated his linkage and cable assembly with STP which had congealed in the recent cold weather.

As I mentioned in an earlier update the Bosch Fuel Injection / Engine Management manual from Bentley Publishers ISBN 8376-0300-5 can really save you a lot of troubleshooting time on a variety of problems.

Good Luck,:)
Michael

Checked the cold start injector last night to see if maybe it was leaking and it was fine. Took my original aav to work today, pulled it apart and checked the resistance of the heater with a good meter and it was 17ohms. Put 12 volts on it and the oil started smoking off so I take it heat is happening, the 40 to 75 ohms the book calls for is staying important to me. I have to check the connector going to it to ensure 12v goes to the valve and if it stays on. I even had the hunch that the cold start injector circuit and the aav circuit may have been switched somewhere in the system to where the cold start valve runs all the time and the aav only gets a slight shot of power. I have a new thermo time switch and now I am wondering if there are more than one model for the 928 and I just simply have the wrong one. Tonight I am going to run my own wires to the aav and start the car, connect it to 12 volts see if the idle drops. I know the valve that is on the car now does close shortly after applying 12v. Also wondering, I see the cold start system gets its air from the rear of the heads. What is the supply of air coming from? Intake air? Exhaust air? Could I have a head gasket leaking forcing excess air through the cold start system? When I pinch off the large air line going to the throttle body from the aav the idle drops very low to where I would have to back off the idle screw to keep it running.

on the 85/86 and 84 cars its quite possible to swap the temp sensor wire connector with the AAV circuit this will send 5 V to the AAV instead of to the temp sensor .
This wont let the AAV operate correctly. The downside is that the temp sensor has now been given 12V and is now burned out as it runs on 5v so it need replacing

I remember you telling me that before mrmerlin, I did try to see if they could be swapped and it just looked wrong the way the harness is laid out. So I checked the voltage of the aav with the key on and it came up 12v, I want to see if the 12v stays there while the car is running. It is strange that I havent heard much about this happening to others. But then I thought that maybe most people dont run this car in the cold. I see the harness for the time temp switch is separate from the harness for the aav, I am guessing the multi pin plug on the inside right front fender is where the connection is made. Does the time temp switch send the 12 volts to the aav directly? or actually does anyone have a wiring diagram for an 84? I have the manuals on pdf but the wiring diagrams were left out. Another question is, is the aac valve supposed to shut off air flow completly after car is started and warmed up or does it allow a metered amount of air while driving. If it isnt supposed to close completly, the cars high idle may not even be from the aac. I was told to check mechanical componants in distributer, but all seems fine. The only reason why I might suspect something there is how the idle changes if I move the distributer. Clockwise speeds it up and counterclockwise slows it down. Applying vacuum to distributer speed it up also.

I got the shoulder bolt made of stainless, if anyone wants one let me know I will have several made at a time.http://forums.pelicanparts.com/uploa...1267882391.jpg