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Stepper motor idle control on 2JZ startup rpm spike

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Stepper is working correctly, higher numbers make lower idle rpms.

I have the cranking steps number as high as possible (100) but the engine still revs too high each time it starts.

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Pull the start up steps to a smaller number ( on these a lower number will give a lower idle increase) 

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I've seen 2J's with the stepper wired backwards before, so rpm increased as the idle table numbers were reduced

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The car arrived with increasing numbers in the base position table at higher temperatures, a bigger number makes a lower idle.

I have never had a car where bigger numbers made lower idle but i'm not familiar with stepper motors, most things I tune have pwm valves or nothing at all.

This seemed wrong to me, but the help file says, "If you find that increasing the number in the idle base position table causes the idle to increase then the stepper motor is wired in reverse"
 

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To clarify, with a stepper motor a larger base position number means less air/lower idle speed.  So it sounds like you have that part right.  The "start up step" subtracts from the base position number so it works more like how you expect it to - a larger start up step gives more air.

It sounds more like maybe the stepper reset is not happening correctly on power down, is this a supra plug-in ecu or a wire-in ecu? 

Perhaps you can do a short PC log of a start up so we have some data, - turn ignition on, start logger, then start engine.

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Can you do another log with the start up step set to zero.  For some reason in that log there is a whole chuck of data missing, it jumps straight from 200RPM to 1800RPM.  Also a copy of your tune would be helpful.

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On ‎7‎/‎12‎/‎2019 at 9:16 AM, Adamw said:

Can you do another log with the start up step set to zero.  For some reason in that log there is a whole chuck of data missing, it jumps straight from 200RPM to 1800RPM.  Also a copy of your tune would be helpful.

Thanks

With the step at 0 it struggled to start, now set at 25 tapering down to 18 when hot.

This solved the issue for a few days. Now on the first cold start of the day the idle sticks 1000rpm above my open loop target throughout the whole warmup, a key cycle cures the problem.

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