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Registered
Join Date: Nov 2012
Location: Chico, CA
Posts: 329
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'78 SC Faulty Auxiliary Air Regulator Causing Slow Cold Idle?
My '78 SC has not idled right since I've owned it. If I set the idle when it's warm, it dies when it's cold. Set the idle cold and it idles way too fast once it's warmed up. I am thinking the AAR may be the culprit. I took it off today and, cold, I can only see about a 1/8 inch opening looking through it. Hooked it up to 12 volts on the bench and the opening seemed to get a little smaller. Then, I temporarily replaced the AAR with a piece of tubing and started the motor. It ran at about 3000 RPM cold. So, it seems like bigger opening, more RPMs. I found the picture below showing an AAR that seems to open a lot more than mine. So, I'm about ready to replace mine but I'd like to hear if others think I'm on the right track.
Thanks, Craig 
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11-11-2015, 04:50 PM
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Auxiliary air regulator........
Craig,
The picture of the AAR shows that it has been opened before by the evidence of the four (4) missing rivets. The normal opening when cold is about 1/4 to 1/3 quarter moon shape and yours looks like close to it. Check the heater resistance (Ohms) and post the value. It looks like you have the -209 (?) which is the correct AAR for '78-'79 SC. How long does it take to close the valve by applying 12 volts? And if your cold idle is going over 2K RPM during a cold idle, do not blame the AAR even if it does not close at all. You have other related problem/s that causes the engine to rev more than it should. You are getting too much fuel during the cold start, a properly set up CIS should not idle cold more than 2K RPM even during dead winter. Keep us posted. Edit: misread your post thinking it was your AAR in the picture. Tony Last edited by boyt911sc; 11-11-2015 at 06:18 PM.. |
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11-11-2015, 05:33 PM
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Location: Chico, CA
Posts: 329
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That's Not My AAR
Probably did a bad job of explaining my idle problem. I have no fast idle when the motor is cold. I have to keep my foot on the gas or it will die. I took the AAR completely out of the car and replaced it with a piece of tubing. THEN it started and ran at about 3000, without my foot on the gas which made me think if the AAR were to open farther, my motor might idle when cold.
The AAR above is not mine. I included the picture because it looked like it opened farther than mine. Mine is below, and in the picture it does look like it opens about the same. I get 33 ohms across the two terminals. It takes about 3 minutes to close with 12 V on the bench. It is a 201, which sounds like it could be the wrong one if a 209, as you state, is correct for my motor. 
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11-11-2015, 06:45 PM
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CIS components........
Quote:
Craig, Is your engine a RoW/ Euro spec.? If it is a USA/Can spec. it should have AAR-209. However, if you have a Euro spec. CIS engine, AAR-201 is correct. What is your WUR number? What is the engine number? Tony Last edited by boyt911sc; 11-11-2015 at 07:05 PM.. |
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11-11-2015, 07:02 PM
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Join Date: Nov 2012
Location: Chico, CA
Posts: 329
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RoW, so I guess the 201 is correct. Whew! Engine number is 6382473. Couldn't quite make out the numbers on the WUR, but last five are 40069. Guess I should look at my title and see if I'm "numbers matching"
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11-11-2015, 07:19 PM
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Join Date: Nov 2012
Location: Chico, CA
Posts: 329
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Update: Reinstalled the AAR and tried going about 1/3 turn rich on the mixture. Big difference; I now have fast idle when cold and motor slows to normal idle as it warms and AAR closes. I'll confirm with exhaust gas analyzer, but I think I may be in the clear. Seems logical that lean condition could interfere with fast idle during warm up.
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11-12-2015, 04:23 PM
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