[StuieUK]

hey guys,
Not a fault thing here, just curiosity...
I got a 2017 335d.
It is mapped to 370, i do have the EGR coded out/blanked.

My daily drive for work is avg 50 miles, which is A roads (upto 60mph until i hit traffic), along with motorway crusing at other times, etc etc ....
Service every 10k miles, etc etc etc, IE: i look after it

For months now, when i plant the foot to the floor, and keep it there, i can see black smoke in the rear view...
Not heavy smoke, but i can see it...
I dont get black stains on the bumper either, and driving normal = no smoke, its only when foot is pressed hard to the floor...

1st thoughts are: Over-fueling ?
Could it be, as its mapped, and i am telling the car to wake up, bangs in extra fuel, hence the bit of smoke ?
IE: nothing for me to be too concerned about (just passed an MOT, service 2k miles ago, etc etc)

[Allworth]

You have a bad fuel to air mixture, it doesn't burn properly, poor timings, and is to do with an engine mapping of course and possibly EGR out. Likely to develop in a bigger issue soon; stuffed engine, worn off components, DPF malfunction, and the list is not exhaustive! Typical scenario when people think they can make a car better than engineers who created a car.

[TurboWeasel]

Is it when holding the revs at say, 3000, in manual mode and then nailing it when you get the space? That sudden and large fuel demand can kick out a bit of smoke but shouldn't be excessive.

Assume you still have the DPF in place?

Has it always done that since the remap and EGR code out, or just for the last few months?

The tuner might have gone too far past the smoke limit and possibly turned off component protection as well, which is a big no no. The BMW map has a very tight grip on smoke control, even the MPPK map. Most remaps don't care about producing excessive soot.

[Ofield_94]

I have a remapped 430d by Unicorn Developments (Done 2 years ago) and the car still behaves as standard with no smoke under any circumstances. My first port of call would be to get it flashed back to standard, secondly try a different mapper if it's kicking out excessive smoke. Maybe also try run v power diesel for a bit.

[Watsey]

My 30d has been remapped for around 80K miles. Zero visible smoke, and the annual MOT emissions test is always an easy pass (last test gave an averaged result of 0.02 against a limit of 0.30 between 678-5331 rpm).

If you're seeing smoke there's something wrong with the remap and/or the DPF.

[StuieUK]

hey guys..
DPF and so on, all in place....
I had the EGR cooler recall done, of which BMW Cotswold reset my map.
My map & gearbox is done by Avon Tuning, very reputable.
The Map was done way before the Recall.

I had the EGR blanked and coded out by the same tuner. Why ? no idea, figured it didnt do much anyway, and if BMW cant design a component correctly, i'll disable it for now.
Emissions are OK MOT wise, as its gets MOT'd by any old garage.

Earlier driving home, i drop the gears so am at 3k rpm, apart from louder, dont see any smoke, and driving at 4k rpm, no smoke (mpg dont look so pretty!).
Booting it from those rev's doesnt give much room as i hit the limit quickly, but cant really see any smoke doing it like this.

Its that initial fast plant of the foot, keeping the foot planted, i see a trail.
To paint a picture of that trail, its not black smoke, its like faint black, as if i blew out some soot, but not dark enough to bother the Ninja bike rider on my tail.....
Or to say it another way: its a light black whisp of smoke i can see (not the same as when i see some diesel cars plant the foot and a thick smoke bursts out, or the exhaust trails a black smoke)

I was wondering if having the EGR delete, which would in theory put the exhaust smoke back into the engine, with it skipping that, would that drop out a smoke ?
I cant get a photo of it either, as it wouldnt be dark enough to see...

As said, its a curiosity thing, i'm still getting 49.4mpg average on motorway cruise, and 1mpg when booting it
To note, i dont boot it that often...
The smoke scenario, i noticed it after the EGR delete 11 months ago, but in terms of that notice, less than 10 notices...

[Watsey]

In that case I wouldn't worry about it, unless it worsens. There's a chance that it could be caused by some oil weeping from the turbo and being immediately burnt off. When the turbo on my 30d was on the way out it started saturating the DPF when the engine was idling, but the smoke was much heavier than you are reporting when accelerating.

As you say, Avon Tuning seems to have a good reputation (I've chatted with them a couple of times and they came across well), and I don't think having the EGR coded out will be the source of a problem.

[StuieUK]

cheers

as said, no issue, car performs great, was just curious on possibilities..
I defo have zero leaks on my drive-way

[TurboWeasel]

EGR is only a tiny portion of the total exhaust volume, and it's turned off when the engine is making power anyway. It's only enabled for light - medium engine loads.

If you can see smoke, it's the remap. The fuel to make the extra power has to go somewhere.

[Eddamoo]

You could have a minor boost leak or a dirty MAF.

6 months ago, I had to renew a boost-hose o-ring (the one just before the EGR gas enters) as i could see the signs of oil weeping out of the pipework. Its not leaked since. Inspect all your boost hose connections and look for any signs of weeping as leaking boost will also make some oil vapour escape.