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Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - trebor1
Followed a very seriously smoky 5 series estate along the main road at 60mph then into oxford. Each time he accelerated ( even gently) it was awful. Mid grey colour I’d say but serous amounts of it. Stunk my car out . What is the likely cause of that on a relatively new car? Not my car so purely interested what is making it pollute our world.
Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - gordonbennet

Could be any of various faults in the fuelling system, but also possible it's been remapped badly for some baseball hatted bod, when you do see really bad smokers under power more often than not there are tell tale signs of bolt on accessory shop tat and dubious stickers giving you some idea of the mentality involved, sometimes those stickers refer to excess Diesel smoke in humourous (facepalm) terms.

Once again, lack of coppers, or rather coppers who can be bothered about such things....and yes i saw a serious smoker only last week which was completely ignored by plod who passed by seemingly without noticing.

Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - dieselnut

It's probably the turbo oil seal gone.

It will be using up engine oil at a great rate, so won't be running much longer.

Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - Brit_in_Germany

Or the EGR is about to incinerate the car.

Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - daveyjp
I followed an Astra Ecotec last week, 15 reg and every time the car pulled away there was a plume of grey smoke and smell of burning oil. Not a good advert.
Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - craig-pd130

If it's greyish smoke, it's an active DPF regeneration taking place. The soot in the DPF is being 'coked' into ash at a temperature of over 500 celsius by injecting extra diesel into the exhaust gases.

It's effectively the same as when the soot in an old chimney starts to burn. If the DPF was fairly full, the regeneration can last 10 to 15 minutes.

A crudely remapped diesel puffs out clouds of black smoke.

Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - edlithgow

Mine smoked a fair bit when I re-actvated it recently. I thought it might be an unsuccessful re-fastening of the exhaust flange, but it stopped after a few k so that seems to be OK so far..

I'd treated the outside of the pipe with aluminium and sunflower oil so that was probably it cooking off. Quite likely a complete waste of time but since I had the pipe off anyway I thought I'd try it.

Also crumpled a beercan inside the downpipe, which I've done before, That doesn't seem to smoke much but I suppose some paint/coating must burn off.

Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - bathtub tom

A colleague was aware exhausts tended to corrode from the inside, so he thought he'd paint the inside of his exhaust by pouring paint down it. I'll leave the results to your imagination.

Bmw 5 series estate 65 reg - Followed a smoke emitting car it was horedous - trebor1
If this smoke is due to ‘regeneration’ how is this in any way environmentally friendly? Are the emission results for road tax purposes including a regeneration? Probably not! Therefore will we be having another VW Diesel type situation in the future once this becomes a noticeable problem in society? I drive a diesel so not being judgmental in any way.. Just a thought.....