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E36 Plugin Idle Misfire?


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The engine is an M50 with S52 crankshaft (89.6mm) and 85mm forged pistons 9:1 compression. M3 camshafts as well

I have not verified timing with a light and I understand that is likely the first question for me. 

I am curious if my question can be answered without this info although I understand if not

I have played with idle ignition, fuel, and idle control solenoid to reach target  idle RPM in open loop

With higher ignition timing and less solenoid opening I hit the target somewhat well although I couldn't tell if I was hearing a slight misfire. So my thought process was to lower the idle ignition target back to 10 where it started and this should lower chance of pre ignition. With a higher idle solenoid opening, less ignition advance, and a little more fuel the idle sounded to improve although still cannot tell if there is a slight misfire.

I am wondering if I am potentially hearing unburnt (in cylinder) fuel escaping the cylinder on a very small level, similar to a pops and bangs tune but obviously less RPM. The idle ignition control would drop down to around 8 with the min clamp I had set. Would this be low enough to allow combustion into exhaust very slightly to sound similar to a small misfire?

Please let me know if any conclusions can be drawn from this log. My AFR didn't seem to go high enough to cause misfire, however I am a novice and likely lack understanding all around. Thank you.

idle help.llgx

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I dont see anything of concern in there, get the rest of it tuned first and leave idle tuning until last.  An idle ignition target of 5-15 will work fine on nearly any engine and certainly a min clamp of 8 isn't the cause of your suspected misfire.  I would typically start with a target of 10, min clamp of -5 and max clamp of 30.  Proportional gain of 1.0

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