rich closed loop idle and idle surge on warm start

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Jan 17, 2015 | 01:39 PM
  #1  
My car idles rich like 12.0-12.5 in closed loop and if I turn my car off and then start it shortly after the rpms go up and down over and over until its fully warmed up. any ideas what could cause this? I just replaced the front o2 sensor and replaced my aem wideband sensor so I know that's not it. I also set the rpm at 900 rpms with the biss screw with the actuator enabled in evoscan. I was thinking the only thing I haven't replaced is the iac valve. Any thoughts on what could cause this would be great, Thanks.
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Jan 17, 2015 | 02:44 PM
  #2  
1) When you shut off the car while it is idling at ~12, what is the coolant temp? warm or still cold?
2) the oscillation in the rpm u are describing after the quick restart, how much is it off from your idle target? meaning how high does it go “up & down”?
3) Has this issue always been experienced? Or it happened after u made the biss adjustments? And what do u mean “with the actuator enabled in evoscan”?

Your best bet is to log the event in evoscan and share the data so we see what ur target vs actual is doing. Log the following coolant temp, rpm and idle taregt, load, iscv steps, afr actual and target.
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