Car has black heavy smoke after driving a few miles; very obvious at stops.
Black heavy smoke on 2002 BMW 745i
The N62 engine in your 7 series has a few reasons why that would happen. We would have to look at it to determine what is actually happening to get a solid diagnosis.
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black smoke is very excessive fuel - should not drive as it will take out your catalytic converters - possible causes , stuck injector/coolant temp sensor failure/low compression/maf sensor failure ect... ect...