[EdB]

2010 model BMW 320d E90 N47 engine 250 000 km (155 000 mi)

For the past couple of months I've noticed a distinct rough cold start on our car with a plume of black smoke. This only lasts for a few seconds (or less than a minute), then it smooths out.

Also note:

• no mods, stock standard
• new battery fitted recently
• new OE intake manifold done (was badly caked up and flaps seized)
• no warning lights at all appearing
• EGR recently cleaned as well, although it wasn't very dirty by any standard

I don't suspect a boost leak because a boost leak won't last less than a minute.

Now I know something is off, but I am not sure how to go about it. I certainly don't want to go on a parts replacement spree. The black smoke on start up is fuel right?

If it is indeed an injector leaking, or injectors leaking, can you diagnose it with a code reader?