Warm start misfire

GeorgeThe4th · 02-08-2024, 02:14 PM

Good afternoon all! Just looking for some help here. I’ve been dealing with a warm start misfire for quite some time on my 16’ X3 with the N55 and want to figure it out. When cold it doesn’t misfire but when I start it after sitting 20 minutes to a couple hours it brings the revs up then when it starts to find the idle it will misfire for 10 seconds or so. I’ve gotten a smoke test machine and so far from my testing confirmed no air or vacuum leaks. Wondering if anyone could take a look at some logs I had and help me interpret them and find the culprit through that. If that is possible what parameters would need to be logged? Thank you!

mwat · 02-08-2024, 02:32 PM

As soon as you switch out of park does it stop?

If so I think this is just normal N55 nonsense. Cold start mines fine. Warm sometimes it'll do a funky misfire thing for a few seconds but nothing awful. You switch to Drive and it's over. I hardly even notice it anymore.

Fairly certain it's just a quirk of the N55.

02-08-2024, 02:14 PM	#1
GeorgeThe4th New Member 0 Rep 9 Posts Drives: 2016 BMW X3 xDrive 35i M Sport Join Date: Feb 2022 Location: Maryland iTrader: (0) Garage List 2016 BMW X3 xDrive 35i [0.00]	Warm start misfire Good afternoon all! Just looking for some help here. I’ve been dealing with a warm start misfire for quite some time on my 16’ X3 with the N55 and want to figure it out. When cold it doesn’t misfire but when I start it after sitting 20 minutes to a couple hours it brings the revs up then when it starts to find the idle it will misfire for 10 seconds or so. I’ve gotten a smoke test machine and so far from my testing confirmed no air or vacuum leaks. Wondering if anyone could take a look at some logs I had and help me interpret them and find the culprit through that. If that is possible what parameters would need to be logged? Thank you!
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02-08-2024, 02:32 PM	#2
mwat Second Lieutenant 125 Rep 283 Posts Drives: E46 M3 & LCI X3 35i M Sport Join Date: Jul 2014 Location: South Florida iTrader: (0) Garage List 2016 BMW X3 35i [0.00] 2001 BMW M3 [0.00]	As soon as you switch out of park does it stop? If so I think this is just normal N55 nonsense. Cold start mines fine. Warm sometimes it'll do a funky misfire thing for a few seconds but nothing awful. You switch to Drive and it's over. I hardly even notice it anymore. Fairly certain it's just a quirk of the N55.
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