Bought vehicle with this problem. I've been told it was the injectors which were causing a problem while running. Vehicle was delivered on a trailer, did run while backing off trailer but was extremely smokey (white smoke) while running. Dropped the oil out of sump & there must have been approx. 5 gallon in oil & diesel out of the sump. topped up with oil & tried to start vehicle but wouldn't start.
yes, these symptoms point most likely to an injector faults - possibly one in sticking open or they are grossly over fueling. If you can peer into the cylinders and see if any pistons look clean that would indicate a problem on that cylinder. Alternatively, a diagnostic on a high end BMW scanner which can read live data and all faults will also be helpful and narrowing down the exact cause.
Sorry if you were hoping for a different answer, please don't shoot the messenger - I can only give the honest answer, which I have. Please remember that a low rating PUNISHES me for my honest and prompt response, and I receive nothing for my time and answer until a positive rating is clicked.Please let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle.