F25 N55 engine problems

[BimmerDave007]

I have a 2013 x3 35i with 170,000 miles. Recently it’s been misfiring at idle and low rpm. It seems worse when it’s warmed up and maybe even worse in hot weather. But it runs fine at highway speeds or really any speed 30mph+. It’s got new plugs and new injectors. It had new ignition coils but it didn’t fix it so we removed them. It’s at the dealer and the next thing they want to try is the DME. They say the DME is sending wrong signals to 3 of the ignition coils. The trouble is I don’t know if I trust their recommendation because they keep getting it wrong. Has anyone else experienced this? The dealer claimed a used DME cannot be used. Is this true? I’m in Indiana anyone know of anyone really good to diagnose this?
Thanks for any help.

[dano1200r]

I don’t know if I trust their recommendation because they keep getting it wrong. Has anyone else experienced this?

Heck yeah. At least buy a reader from Amazon for 39 bucks or get a real diagnosis at an independent shop. You'll lose your ass if you let them change parts unless they are going to refund your money and put your good dme back on their dime. A good tech could figure out a bad dme without you buying a new one to test their hunch.

Sent from my SM-G965U using Tapatalk

[BimmerDave007]

Could the issue be carbon? Could anyone direct me to someone with more knowledge?

[BMW323iDude]

Wow 170k is impressive for a 2013.
If you haven't had a walnut blast to clean out the carbon from the valves, I would suggest that as a good starting point. Plenty of vids on youtube showing the results of direct injection engines as low as 60k miles with tons of buildup preventing airflow.

[BimmerDave007]

Yea, I’m considering doing that. I have seen tons of stuff on walnut blasting n54s, but not n55.

[BimmerDave007]

I’m getting it blasted. If this doesn’t work chances are really high that I trade it in.

[BimmerDave007]

Got blasted. It did nothing. I called BMW NA and I doubt it does any good.