the car shakes and there is black smoke covering the back

[h6mid]

Hi guys,

Recently my car went to dealership for drivetrain malfunction since it was shaking really bad. They claimed they fixed it but sometimes I still get some minor shakes while waiting behind red lights. Also everytime I take the car to carwash, the back is covered with these black particles (i think its black smoke) as soon as I get home. Has any of you experianced such a thing? I have a 2012 650i xdrive. I have attached some pics right after carwash. Is it normal to have the back covered in those smokes in winter?

Thanks in advance

[j_d_valle]

Did you eliminate the cats? Cause otherwise i cant figure this being "normal"

[h6mid]

No I haven't done in modifications to engine or the exhaust.. I have gone to dealership for at least 8-9 different issues in the past 9months that I just sometimes want to avoid it )
but I guess I should go there again. I would like to direct them though since they keep changing stuff that are not really the issue there.

[bravo261]

i also had the drivetrain malfunction, but i don't get that grime RIGHT after a carwash, but maybe 200 miles later, i do get a cloud of dust that is annoying. it would be much finer than what you show there as well...and keep in mind i'm in southern california weather

[h6mid]

Originally Posted by bravo261

i also had the drivetrain malfunction, but i don't get that grime RIGHT after a carwash, but maybe 200 miles later, i do get a cloud of dust that is annoying. it would be much finer than what you show there as well...and keep in mind i'm in southern california weather

You mind telling me exactly what did they repair after your drivetrain malfunction? Also do you still get any shakes at all while waiting for the traffic light? I contacted the dealership today and they say it could be from the road, and the shakes need to be confirmed by a roadtest to better direct the repair team. But the problem is that the shakes are so random and I can't really reproduce them... And they also told me that the smoke could be just from the road (specially if you are passing construction zone which I never do).

[h6mid]

this is what SA told me:
So I have shown my workshop foremen the pictures you have sent me and explained your concern on the condition of the rear trunk and bumper. He has advised to me that this would not be caused by the exhaust system and that it would defiantly be caused by dirt from the road. Hope this helps but besides that we will see you on the 17th.

[vaio23]

My car doesn't shake but it has the same black dirt on the rear like yours. Since it is white it is very noticeable, I always assumed it was from exhaust since the rest of the car doesn't have it.

[drmlee]

mine has the black dust on it too after driving a few weeks without wash. I always assumed it was brake dust.

[Chas_97]

the reason for the shaking of the car body & the smoke coming out of the exhaust tailpipes is due to excessive fuel getting dumped by the fuel injectors. Sometimes this can ruin the catalytic converters and foul out the spark plugs.
In my case it blew a hole out of the side of the catalytic converter and a fireball escaped upwards and burnt the foam hood insulator material.
In my case the DME banks failed, which caused the high pressure fuel pump to fail and so on...
It's a big problem with these high pressure (2900PSI) fuel delivery systems and BMW has a major quality & safety issue on their hands.
Of course I'm speaking from my own experience here.