IAC valve or not?

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Spryboy1974
Posts: 33
Joined: Fri Aug 03, 2018 10:02 am
ECU Model: S40 Pro

IAC valve or not?

Post 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?? :?
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ignitionautosport
Posts: 577
Joined: Wed Jul 27, 2011 5:30 am
ECU Model: S80 Pro
Location: New Zealand
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Re: IAC valve or not?

Post 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 :)
| '94 GSR Lancer | '96 Toyota Carib 20V | '83 Toyota Starlet | www.ignitionautosport.co.nz |
Rob Stevens
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Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: IAC valve or not?

Post 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.
Spryboy1974
Posts: 33
Joined: Fri Aug 03, 2018 10:02 am
ECU Model: S40 Pro

Re: IAC valve or not?

Post by Spryboy1974 »

Thanks for the reply chaps, was hoping I didn’t need it! :D
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ignitionautosport
Posts: 577
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ECU Model: S80 Pro
Location: New Zealand
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Re: IAC valve or not?

Post 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.
| '94 GSR Lancer | '96 Toyota Carib 20V | '83 Toyota Starlet | www.ignitionautosport.co.nz |
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