Diesel - why clouds of black smoke?

atrixblue.-MFR-.

GolfBravo wrote: »

Diesel Particulate Filter.

not always. DPF does usually dump when the system isnt heated for a burn and they didnt fit those octavia's with DPF's untill the 2.0TDI engine came out later on.

most common is the exhaust system has persihed inside one of the center boxes or rear muffler the wirewool stuff then gets blasted on accelleration when its loose and tend to release the soot that its clogged up with.

WTFH

There's been a few times when I wish there was a dump switch for the DPF, but mostly that's when my vindictive side comes out.

Weird_Nev

andygb wrote: »

as I watched the missus leave for work this morning, I realised that there was something missing - clouds of black smoke - even a hint of smoke.

GolfBravo wrote: »

Diesel Particulate Filter.

Andy: I'd bet that a decent number of cars belching black smoke have had bad remaps done, or else had those cheap ebay "tuning" boxes fitted to them. They just trick the ECU into overfuelling to boost engine power, with the side effect that combustion is not complete and soot pours out.

My dad used to have a Range rover with an Isuzu diesel engine swap. Proper smoke screen maker on full throttle.

GolfBravo

motorguy wrote: »

Unlikely that a 7 year old 1.9TDI has a DPF.

From memory it first went on the 2.0TDI

A 7 year old Skoda = 2006 build = Euro IV = some VAG 1.9 TDIs had DPF fitted from 2006 because of Euro IV (engine code BLS). PD VAG engines definitely don't have DPF (the fuel injection system is incompatible with DPF), but I doubt PD injected engines were still available in 2006.

Not sure which models though, VAG like to change their engine specs on a regular basis.

Surely a VAG car would have the DPF option code listed (if fitted) on the first page of the service book, just need to find what the DPF option code is.

GlynD

Reasons why a diesel engine would produce black smoke:

• Incorrect timing
• Dirty or worn injectors
• Over-fuelling
• Faulty turbocharger (ie not enough air to match the fuel)
• Incorrect valve clearanceIncorrect air/fuel ratio
• Low cylinder compression (eg sticking piston rings or worn components)
• Dirty air cleaner
• Restricted induction system (eg system too small or kinked inlet piping)
• Other engine tune factors
• Poor quality fuel
• Excessive carbon build up in combustion and exhaust spaces
• Cool operating temperatures

If yours isn't Andy then it's well maintained and functioning as the manufacturer intended.

londonTiger

People saying the it cars don't smoke, if they did you wouldn't know. It will not show up in your rear view it wold dissapitate before you could get far enough to see. You will usually get that at the start of drives when the engines are not hot enough so fuel burns rich. Usually thick black smoke is diesel, petrol cars will have bluish gases with some black smoke

Ultrasonic

GolfBravo wrote: »

A 7 year old Skoda = 2006 build = Euro IV = some VAG 1.9 TDIs had DPF fitted from 2006 because of Euro IV (engine code BLS). PD VAG engines definitely don't have DPF (the fuel injection system is incompatible with DPF), but I doubt PD injected engines were still available in 2006.

According to wikipedia, all MkII Octavia 1.9 TDi engines were PD, and they were sold as late as 2010 (see here).

GolfBravo

Source: VAG

Skoda have gone through quite a few 1.9 TDI versions!

GolfBravo

Ultrasonic wrote: »

According to wikipedia, all MkII Octavia 1.9 TDi engines were PD, and they were sold as late as 2010 (see here).

Well in that case the reason for lack of black exhaust smoke is [strike]Diesel Particulate Filter[/strike] a very efficient fuel injection system.

The other cars? With black smoke? Most likely the drivers really giving it some berries (trying to rev it like a petrol engine).

gilbert_and_sullivan

Usually but not always excess or unburnt fuel.

Excess in some cases because thats how they get the headline grabbing max BHP figures, whilst miraculously being so clean as to make free or super low VED.

Factor in attempts to raise the performance by some means, and the only way to do that is to put more fuel through, leading to black smoke at some point.

You might think you're own non DPF Diesel is as clean as a Prius, but stick your foot down hard when its dark and you have cars following, whilst you may not see the black smoke in daylight you'll see all you need to in the headlights from behind.