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IAC valve or not?

Posted: Sun Aug 12, 2018 10:27 am
by Spryboy1974
Have some bike throttle bodies on the way for my Megane engined Reno 19, question is what do I do about the IAC valve for cold start or will it be mapped just relying on the ECT sensor for cold start?? :?

Re: IAC valve or not?

Posted: Mon Aug 13, 2018 3:32 am
by ignitionautosport
I've successfully used ignition timing idle control, it works amazingly and if you can't be bothered fitting IAC then it's more than acceptable.
You have to set the throttle closed position slightly more open than usual so it has enough air to idle when cold, and the ecu trims out timing to bring the idle back down as it warms up. All closed-loop, it's like OEM control :)

Re: IAC valve or not?

Posted: Mon Aug 13, 2018 8:16 am
by Rob Stevens
2nd that.
I have ignition based idle control working very well. The only trouble is that as above you need to set the butterfly open a fair bit to get the cold idle up and the pid loop will use say 30 deg of advance to idle. but then once hot it has to bring in something like 0to2 degrees timing which tends to make it run hot .
But it does work very well, using the idle 20x14 base table allows the idle to slowly settle to prevent stalling.

Re: IAC valve or not?

Posted: Mon Aug 13, 2018 12:44 pm
by Spryboy1974
Thanks for the reply chaps, was hoping I didn’t need it! :D

Re: IAC valve or not?

Posted: Tue Aug 14, 2018 1:11 am
by ignitionautosport
I guess it depends on the engine/atmospheric conditions, I have set one up that sat around 25degrees cold and 5 hot. I did adjust the throttle once it had warmed up to get it around there then rechecked it still worked when cold.