B58 Misfires after stage 2 catless tune

Ahmed1114 · 07-10-2025, 11:58 PM

I have a 2017 540i that I got a catless downpipe for and a muffler delete, I recently tuned it to stage 2 with MHD and I started getting misfires, at first I thought it was the injectors and spark plugs and coils so I changed all of them but that didn’t help, I don’t know if I need to retune it becuase maybe the tune was for catted downpipes but I’m getting white smoke on start up until it’s warmed up, attatched are all the codes I’m getting. (I already got rid of the low oil code) if anyone knows what’s wrong or had the same issue I need some help please.

335xiRyan · Yesterday, 04:56 PM

I thought I read somewhere you can send logs to MHD and they will help diagnose.

07-10-2025, 11:58 PM	#1
Ahmed1114 Registered 0 Rep 1 Posts Drives: 2018 540i Join Date: Jul 2025 Location: Texas iTrader: (0)	B58 Misfires after stage 2 catless tune I have a 2017 540i that I got a catless downpipe for and a muffler delete, I recently tuned it to stage 2 with MHD and I started getting misfires, at first I thought it was the injectors and spark plugs and coils so I changed all of them but that didn’t help, I don’t know if I need to retune it becuase maybe the tune was for catted downpipes but I’m getting white smoke on start up until it’s warmed up, attatched are all the codes I’m getting. (I already got rid of the low oil code) if anyone knows what’s wrong or had the same issue I need some help please. Attached Images
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Yesterday, 04:56 PM	#2
335xiRyan Enlisted Member 14 Rep 45 Posts Drives: 2008 335xi Join Date: Dec 2017 Location: Minneapolis, MN iTrader: (0)	I thought I read somewhere you can send logs to MHD and they will help diagnose.
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