Idle Tuning and AC

Tuning, troubleshooting and the nitty gritty of using rusEFI to make your engine run nicely!
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10AE0739
Posts: 15
Joined: Mon Aug 15, 2022 7:02 pm

Idle Tuning and AC

Post by 10AE0739 »

I'm looking for advice on tuning Idle with AC. I had it working decently well before I installed an 11.7 lb flywheel on my 99 Miata. So far my idle tuning method has involved plenty of open loop IAC, AFR around 14.1, base timing around 10, and closed loop idle timing turned on and set to min/max of -10 and 17. With the higher IAC duty cycle, the timing spends most of its time retarding to about 5-7 to keep Idle RPM at 900. When the RPM target jumps up to 1100, the timing immediately jumps to 27, helping to bring the RPM up, but usually not fast enough. I also have closed loop idle activated and once the RPM settles, it provides the extra air needed by the compressor. Open loop AC Adder is set to 0. Timing with AC compressor on is usually 10-12 degrees. My tune and logs are posted online. I've posted in the github suggesting an AC compressor delay timer. I believe other ECUs have this option. If the RPM target could be told to increase and then the compressor comes on 500 milliseconds or 1 second later, I think tuning would be much easier. I'm new to this, so any advice is appreciated. I plan to put together a detailed introductory post about my car soon.
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AndreyB
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Re: Idle Tuning and AC

Post by AndreyB »

Will try to make progress today
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10AE0739
Posts: 15
Joined: Mon Aug 15, 2022 7:02 pm

Re: Idle Tuning and AC

Post by 10AE0739 »

For anyone that comes across this thread, issue #4500 has been closed and adds a delay option for the ac compressor. This works very well and makes tuning idle with AC much easier. The new setting is under base engine > air conditioning.
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