535Dante

My 2010 535xi experiences the same thing. I actually went in and got walnut blasted for the carbon build-up, but still experience the vibrations on cold engine start-up. Recently, I've been using Lucas Fuel treatment and noticed the vibrations have gotten better.

I'm going to continue to use this every couple of tanks to see if it gets better.

Lotus99

Update from me: Very little difference after the walnut shell blasting... So I'm booked again for next week, but without codes, wondering what they'll do... Coils I hadn't thought of. I'll mention it to them too.

paul535xi

i feel you...

im going thru the same thing, just did my coils and plugs ( according to the codes shown)
same problem: on a cold start the engine adjusts for about 1 min and then settles.

im told that without any new codes being produced its hard to tell what the problem is... but with an educated guess from my mechanic that specializes in bmw is that all 6 injectors should be changed, and also the " Exhaust valve flap" (pardon me for not remembering...)

with no codes all of this is expensive guessing. Only good news is that apparently bmw has a new design for its injectors for N54 and that the problems that we all seem to share (sooner or later) should be fixed

TTuned

i did the de carb service ($850 dealer) on my 335i smooth for a short time or never went away. it did it today, and other random times.
Its under warranty so ill just deal with it till something breaks.

Lotus99

Final update: I went back in, and complained after the walnut blasting didn't do much for the cold startup, and that left only the injectors and the coils as possible culprits. They replaced all 6 injectors, and for the last few days it's been starting up smooth as before! Yay!

Booyaazaa

Glad they finally figured it out. For the past month my startup and idle have been perfect since mine got replaced. I'm thinking of doing their fuel induction cleaning when they replace my plugs to get the engine really purring.

Lotus99

What's this fuel induction cleaning thing? I thought all those fuel system cleaner deals were just $ making things dealers tried to sell you, but didn't do a thing?

Booyaazaa

Yes the normal ones that you dump in the gas tank don't help DI intake carbon buildup. From what I have read its similar to using sea foam/bg44 but my SA is getting me more details about what they do. Also the people who have done the cleaning have had all positive reviews when I googled it. Figured its easier for me to part with $200/250 then over $600 for a walnut shell blasting.

Lotus99

I'd never heard of that service in reading the forums, and the advisors haven't told me about it in all these years. Interesting.

This looks like it, along with a brochure on it?

BMW Fuel Injector and Induction Cleaning service - BMW M3 Forum (E90 E92)
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Booyaazaa

Yep that's it. As soon as my SA tells me the exact process I will probably do it. I know he works for BMW but he even said it worked great on his 335i.