[woodga16]

I kept getting misfires during WOT in cyl. 1 on any map. I switched out a brand new coil two days ago in cyl. 1 because a friend had an extra brand new on laying around and right away I got another misfire, cyl. 1. Today, I had to pass a car quickly and didn't get a misfire. I went ahead and did a WOT run two more times and everything ran perfect. My question: Does a new coil take time to adapt to the DME like a tune or modifications or is this an environmental problem, i.e. today was cold and rainy vs two days ago when it was just cold and dry.

[vasillalov]

Mods?

[woodga16]

FBO+tune

[JamesM3M5]

No, there should be no adaptation time on a coil. The ECU will fire it up to 5 times at idle and with varying dwell time based on load/RPM when driving normally. If there is a problem, the ECU monitors the flyback voltage (there's a third terminal on the coil that's pulled to ground with a 240 Ohm resistor) and checks for proper flyback voltage indicating the coil has fired the spark properly. Basically, it can monitor the coil operation instantly on the fly, no adaptations needed for dwell.

Programming on the N54 (and probably N55) ECUs has drastically raised the misfire threshold - misfire parameters on NA cars are much more sensitive - probably to prevent lots of diagnostics on these finicky turbo DI engines. If you continue to see misfires on cylinder 1 in the codes, there is a definite problem. I'd check for carbon buildup, oil contamination, and possible fuel injector replacement if it continues with good plugs and new coils.

[woodga16]

Wouldn't carbon buildup be constant though? I haven't replaced spark plugs yet, but I would think a spark plug would be also continuous misfire. My car idles fine, every time. Never missed...Thanks James!