Sooty exhaust

ushafiq · 03-08-2024, 12:29 PM

Trying to re-ignite an old thread here with a hope that I would get some answers which I am after!
I have 435xd (N57Z Engine) - had the car for 7 years now, 62K miles. My usage is 40 miles round trip on a mix of A roads and motorway miles - 2 to 3 time a week, and occasional longer motorway journeys or European trips…..not much has changed in my driving patterns over the last many years.

I have started noting a slight hesitation at low speeds over past few months and attributed to cold weather - if I press the accelaortor, the car still wakes up and in sport mode it still get a good blast but, at lower speed it definitely feels sluggish. I always use premium fuel, and change oil every 5K. Full dealership service history is on top - all up top date. I have also noted that my exhaust is sooty which wasn’t the case before. I have also added fuel treatment / dpf cleaners in fuel tank and as such didn’t feel any difference - No fault codes on the dash and I read the dpf readings via OBD scanner and seems all OK - note that there are no mods or remaps on the car- it is completely stock.
Those with N57Z engines please share their experience…the car drives ok but I want to be at its full potential - happy to explore preventative route before it get worst…..already thinking about i) intake manifold and ports carbon build up clean, ii) ZF8 gearbox service, iii) timing chain replacement as a preventive step …..EGR valve recently changed under recall so that should be fine…
I can always book the car with a specialist or dealer but would be good to hear from others.

Wazman999 · 03-09-2024, 02:51 AM

Just use some autosol and 0000 grade wire wool

TurboWeasel · 03-09-2024, 04:35 AM

Couple of things to check:

1) MAP sensor. They slowly fill up with EGR/oil soot. Can just be cleaned out or replace the sensor for £45ish.

2) PCV breather tube. It comes out of the oil filler neck and into the turbo(s). They are notorious for splitting.

Either of those 2 things can affect the fuel metering to some degree.

03-08-2024, 12:29 PM	#23
ushafiq Private First Class 38 Rep 103 Posts Drives: F36 435d xdrive & G01 X3 Join Date: May 2011 Location: United Kingdom iTrader: (0)	Trying to re-ignite an old thread here with a hope that I would get some answers which I am after! I have 435xd (N57Z Engine) - had the car for 7 years now, 62K miles. My usage is 40 miles round trip on a mix of A roads and motorway miles - 2 to 3 time a week, and occasional longer motorway journeys or European trips…..not much has changed in my driving patterns over the last many years. I have started noting a slight hesitation at low speeds over past few months and attributed to cold weather - if I press the accelaortor, the car still wakes up and in sport mode it still get a good blast but, at lower speed it definitely feels sluggish. I always use premium fuel, and change oil every 5K. Full dealership service history is on top - all up top date. I have also noted that my exhaust is sooty which wasn’t the case before. I have also added fuel treatment / dpf cleaners in fuel tank and as such didn’t feel any difference - No fault codes on the dash and I read the dpf readings via OBD scanner and seems all OK - note that there are no mods or remaps on the car- it is completely stock. Those with N57Z engines please share their experience…the car drives ok but I want to be at its full potential - happy to explore preventative route before it get worst…..already thinking about i) intake manifold and ports carbon build up clean, ii) ZF8 gearbox service, iii) timing chain replacement as a preventive step …..EGR valve recently changed under recall so that should be fine… I can always book the car with a specialist or dealer but would be good to hear from others.
	Appreciate 0 Quote

03-09-2024, 02:51 AM	#24
Wazman999 Enlisted Member 403 Rep 41 Posts Drives: F31 335D xDrive Join Date: Mar 2020 Location: Kent iTrader: (0) Garage List 2016 F31 335d M Sport [10.00] 2016 F31 335D M Sport [0.00]	Just use some autosol and 0000 grade wire wool
	Appreciate 0 Quote

03-09-2024, 04:35 AM	#25
TurboWeasel Major 794 Rep 1,013 Posts Drives: BMW 330D Join Date: Nov 2022 Location: UK iTrader: (0)	Couple of things to check: 1) MAP sensor. They slowly fill up with EGR/oil soot. Can just be cleaned out or replace the sensor for £45ish. 2) PCV breather tube. It comes out of the oil filler neck and into the turbo(s). They are notorious for splitting. Either of those 2 things can affect the fuel metering to some degree.
	Appreciate 0 Quote