MY15 Idle Dip and Misfires

[wparsons]

Mine is worse the colder it is outside, and non existent in the summer.

[steve99]

Originally Posted by Tectoniic

Yep that is when the misfires happen. The cylinders that misfire on startup where typically 2 and 3 with 1 or 2 events per cylinder during the whole startup time. Very very occasionally I have had a single misfire on Cylinder 1 during regular driving when the car was fully up to temp but no shuddering when this happened. From the times that I have logged, i have yet to see a cylinder 4 misfire.

From what I can find occasional misfires during startup, especially fully cold starts, are ok if it is not triggering the CEL. I'm just trying to keep an eye on it so I can see if it starts to get worse.

judging by the number if misfires needed to create a CEL the odd one or two counts is insignificant. Not sure what the time period the ecu keeps count though, but its appears the engineers expect more misfire counts at lower rpm

[steve99]

Originally Posted by Gringosteve

Mine is a 2012 and does it all the time

if you have ability to tune set idle to 700 or 750 minium all idle tables also make sure your on A01G or A02G calibration assume your manual or A01I for auto and set pi/di ration as per all three tables cold/warm/hot

[NyC Zn6]

Originally Posted by wparsons

Mine is worse the colder it is outside, and non existent in the summer.

Same here

[504]

not expecting previous thread posters here to respond but perhaps another that will read this,

On E85 my car idles naturally at 20 degrees ignition

on 98 it sits around 16 but dips to 13 sometimes (basically minimum idle timing) and while it holds a strong idle, it makes a faint stumble vibration at such a low timing

what do you guys recommend as a minimum timing for a smooth idle? 20 degrees idles effortlessly but unsure of the risks associated with raising minimum idle to say 16 or 17 even