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Idle air valve Duty Cycle table

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My IACV is spot on on idle, no problems at all but the ecumaster software has another DC table for IACV when idle is not active, please see the screenshot.

My question aplies in general for all ECUs, when idle control is off what DC should the IACV have ? fully closed or opened ?



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You need it closed enough to bring the engine speed down to the range that idle control can take over without stalling (which could happen if fully closed). If the Engine Speed "hangs" and won't return to idle, then you need to close the IACV more. If it tends to stall with the throttle closed, you should try opening the IACV more when idle is not active

Hi David,

thanks for replying.

My idle is fine, doesnt stall on stop signs or anything, my question is, since an IACV is a bypass valve, what DC should i use when off idle like at WOT for example.

I'm sorry if my response wasn't clear.

You should find the value that produces good results (i.e. not stalling or hanging). I don't think that will be either fully closed, or fully open.

Why don't you try closing it fully, see how it drives / responds. Be sure to try free-reving and just close the throttle from 3-4000 rpms.

Then change it to open fully and see how that drives / responds. Try the same free-rev test first.

I'll bet the right answer is somewhere in the middle -- and you would determine that value based on my earlier comments.