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Old Sep 27, 2010 | 10:20 AM
  #1  
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r074r'/ |\|00B
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powerFC idle learn during a/c on

I am still having problems with my idle hunting/surging when I am stopped with the A/C on.
I tried to do the idle learn again this weekend and noticing that during the 10 minute learn with the A/C on, the compressor/relay would kick on and off, which would change the rpm. So it seems like it is stuck learning a/c mode with a/c turning off and on, making it not really learn what rpm to use.

Is there a way to curb this behavior? Is there a relay fix that makes the a/c run constantly (or at least for 10 minutes for it to do the learn)?
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Old Sep 27, 2010 | 05:39 PM
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cewrx7r1's Avatar
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YES, normal mechanical fine idle speed tuning using the air adjusting screw under the throttle body. After all the Mazda/PFC idle control is cheap software/hardware with minimum correctional ability that requires YOUR participation once in a while.
Read the many-many treads on this problem.

Then get at adjusting that screw: CW to reduce air, CCW to increase air.
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Old Sep 27, 2010 | 06:32 PM
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The idle control is probably the most frustrating limitation on this system. Try opening the air adjusting screw as Chuck said. Also try raising the A/C target idle speed and fuel cut speed by 50 or 100 rpm.
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Old Sep 28, 2010 | 11:27 AM
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r074r'/ |\|00B
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I undesrtand the need to adjust the air screw. I've already attempted 3 different adjustments (1/4 out, 1/2 out, 3/4 out).

Maybe I wasn't clear with my first post...

My car idles perfect (cold or hot) until I turn on my A/C. Maybe my A/C is different with the relay fix?
When I turn on my A/C, the grounding relay clicks on and off at different times to turn the compressor on and off. This causes different loads on the engine at different times. When the car tries to learn this, it is learning a bad behavior (IMO). If the compressor were to run all the time, it would learn what idle to use all the time. So since my a/c is fluctuating, natually the idle is fluctuating, causing the idle hunt/surge... no ?
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Old Sep 28, 2010 | 02:15 PM
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I guess the question is: When doing the idle learn with AC on, does everyone's AC go on and off repeatedly?

Mine did, and I assumed it was supposed to because my car was frigid inside
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Old Sep 28, 2010 | 02:29 PM
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A/C compressors cycle on and off all the time, whether it's an Rx-7 or anything else. Trying to eliminate this is not the solution to your problem--you can have your A/C cycle and still get the thing to idle right. Just like you can have your cooling fans cycle and still get the car to idle right. You're placing too much emphasis on the idle learning procedure. It's important but it's not the only thing that determines idling stability.

Do you have idle IG control on or off? What are your idle and F/C speeds? What is the AFR when the idle starts flaking out? Can you post Datalogit maps?
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