The BMW 225D underwent replacement of the rocker cover, head, gasket, and DPF, nevertheless it continues to emit significant black smoke and experiences a loss of power.

[keithmerc220]

Greetings, everyone.

I need assistance with my 2014 BMW 225D.

I observed some smoke emanating from my engine bay along with the engine management light illuminated, displaying a fault code indicating excessive mass air flow. I took the vehicle to the garage, where they conducted a smoke test and diagnosed the issue as a leaking rocker cover gasket. After replacing it, upon receiving the car back, I noticed the exhaust was emitting substantial amounts of black smoke, resulting in the rear of my vehicle being coated in black and a significant loss of power.
I returned the vehicle to the garage, where they diagnosed that my DPF was severely cracked and fragmented. Although I have replaced the DPF, the issue persists. We subsequently removed the exhaust to inspect for soot accumulation, which was present, but we also observed that black smoke continued to emanate from the DPF.

I am quite perplexed on the next steps, since I continue to see black smoke emanating from my exhaust and a reduction in power. The subsequent procedures include inspecting the EGR; however, I had a recall in 2022 during which the EGR was replaced at BMW, or alternatively, I may examine my injectors.

Any assistance would be really appreciated, as I am beginning to feel annoyed with it.

[keithmerc220]

The vehicle is unmodified, with no remapping performed, and it operated normally prior to being taken to the mechanic.

[VWDaveBMW]

It seems that there may be a boost pipe malfunction, resulting in the emission of black smoke.

[keithmerc220]

Could you elucidate? I am uncertain how a disconnected boost pipe would result in black smoke; would it not just lead to a loss of power?

[keithmerc220]

The vehicle has undergone a smoke test; if a boost pipe were dislodged, it would be indicated in the results.

[VWDaveBMW]

The adjustment of fuel based on the volume of air entering beyond the MAF results in inadequate combustion if not all the air reaches the cylinders, leading to an improper mixture that cannot burn effectively.

[DSM10000]

I had same issues with my last 330d when the intercooler-manifold angle pipe fractured. Subpar performance, excessive black smoke, and a loud hissing sound from the turbocharger under load. The new pipe resolved the issue.
Which garage have you selected, and have they conducted a diagnostic assessment yet?
They have to verify not only the stored and existing trouble codes but also the live engine operating parameters. Will promptly provide pertinent information on the engine's status. I can do all of that with my little app-based scanner, which cost me £40, so I am perplexed as to why any reputable shop does not first connect the automobile to diagnostics and analyze live data. They undoubtedly ought to be.
Certainly, the DPF will get obstructed if the engine is not functioning well, which it clearly is not. A diagnosis should have been conducted prior to replacing the DPF, since it will inevitably get obstructed again if the engine is emitting excessive soot and exhibiting a deficiency in power. My intuition is that during the alteration of the cam cover, they likely disrupted or damaged a connection, resulting in a boost leak that has caused your issues. However, given the vehicle did not display such symptoms before to their intervention, I would assert that restoring it to its original condition is the minimum they should do.