2016 X50i chugging/hesitation idle with cold motor

[navyflyer]

Hello all,
I have a 2016 X5, about 80k on motor. My issue is that I start up, I get minor backfiring, and the motor chugs, hesitates, runs rough, misfires at idle and during acceleration up to 40-45, until engine is warm. I can floor it, no hesitation at all. Runs great at high speeds. Definitely better when engine is warmed up. But initially, it’s bad.

Maintenace done so far, 3 trips to shop.
Changed breather hose
4x O2 sensors
Both mass air ducts
Bank 2 turbo valve
Bad #2 fuel injector
All coils and plugs

It did clear up for a bit after the coils and plugs, and the hose/O2 sensors swap, but it’s back now.

What’s left? The rest of the injectors…?

[andrewwynn]

If it more or less runs right when warm but crappy when cold I'm thinking intake carbon.

The official process to Walnut blast n63 starts with 1. Remove engine from the car.

There is intake/turbo cleaner that can be sprayed into the intake past the MAF to clean the carbon. I dont know if there is a way to get a fiber optic inspection camera into the intake to confirm. Some can peek in though the plug hole and have a mirror to look back though the valves.

[andrewwynn]

I just noticed you have 2nd generation of n63; means Valvetronic. The symptom e your describe also match VT colds start issue.

I think it's possible to start with the VT motors unplugged and the car will use the backup throttle plate to control RPM. It will probably limp mode but run without backfire.

I had a buddy with 04 n62 that ran like hell when cold and he would just unplug VT until warmed up then plug back in and it ran perfectly fine when warm.

What scanning solution are you using?

I think foxwell will show the requested and actual VT value real-time.

[navyflyer]

Thanks for the reply. I haven’t been doing the maintenance myself…had two different shops work on it…er…throw parts at it. One a BMW specialist, I gave up on him after 4k and took it to the …gulp…dealer. For another 2k. So, I’m not using any scan tools, gave this one to the pros as I just don’t have time now.

Would gas be an issue? Requires 89+ octane, so we use plus (which is 89), should I run a tank of super?

Is there a fuel injector cleaner I can try?
Thanks.

[andrewwynn]

A scanner will tell you if the octane wag high enough. I would definitely run some Lucas injector cleaner and a couple tanks of premium. I never trusted mid grade in our n63 even though I noticed it's the only engine I've ever seen that has 89 vs. 91 as the minimum. You can also buy a couple bottles of octane boost to bump up the gas in the tank.

Injectors are very pricy on that engine you're lucky to have new enough engine they could replace one. On our 2012 it's an all or nothing.

I started a thread to determine if anybody got away with mid grade in the n63 and never found anybody that confirmed it was ok.

Rough cold start points to plugs/carbon. I'm surprised dealer didn't bring up walnut blasting.

[navyflyer]

Ok, full tank of supreme, and injector cleaner added. Let’s see.

[ard]

^ Would be shocked it that fixes it.


Why not find a shop that has a scanner, KNOWS how to use it and SHARES results and strategy with you?

[navyflyer]

Both had scanners, both were upfront with me and showed me their data. And what they wanted to repair. Each time I’d drive away and it was fine for a week or so, then symptoms came back. Just trying to get some ideas from the group here before I take it back...probably to BMW. Maybe it’s something simple I can fix…

[navyflyer]

I ran a code check. No codes. (except BMW didn’t clear the bank 8 misfire, so I cleared that.) Ran again, all clear.

[navyflyer]

Well, I found my answer. Drove it today, engine light, limp mode. Ran scanner, P0308 Cylinder 8 Misfire Detected…. Back to dealer it goes tomorrow, as they already got that fault and I paid for that to be repaired.