neilkf

Hi All from a Newbie
Three times now I have noticed my Jan 2010 Cayenne Diesel chuck out a humungous cloud of blue smoke behind me. It lasts for about two mimutes, doesn't affect performance and is gone as quick as it started leaving nothing but a pile-up of blinded drivers in my wake.
Porsch's explaination is this: There is a chamber (I guess somewhere in the exhaust system) which collects unburned fuel impurities to give an acceptable emissions reading at the tailpipe. Every so often this chamber dumps it's collection into the exhaust where it is all burned in one go - hence my smokescreens.
It sounds feisible and certainly fits the symptoms but it doesn't seem very environmentally friendly to slowly collect all your emissions rubbish only to dump it in one fell swoop when you can't hold any more. Kinda-like either flicking your dog-ends out of the window as you go or emptying your ash tray in the kerb when it's full.
Does anyone buy this?
Cheers
Neil Foreman

Van1

My Touareg does the same thing. I believe it is just a cycle that the exhaust goes through to clean off the particulate filters. It is kind of embarassing.

JFScheck

Interesting - I've had my Touareg since February of 2010 (V6 TDI) and with 15,000 miles on her have yet to see "blue smoke"....

I know the particulate filters heat up to burn said material - and I am very observable individual - interesting....

ltc

My guess would be the use of low cetane ULSD fuel ...

Divot

Do you take short trips that don't allow the engine to get up to temperature?

Jamo

I've done 13,000km and am also yet to see any smoke.

Where are you, what's on the odo and do you do long or short trips?

neilkf

Thanks for your replies guys. I'm in Kent, UK so there's no such thing here as a long trip. My total miles is about 6K and I must admit to buying the cheapest fuel - but no different to millions of other motorists here. That said, Porsche must know that premium grade fuel isn't always available everywhere in the world. Your comments confirm that this is a designed-in thing and I can live with that, but I'm dreading the day when it decides to burn it's collected pollutants in a traffic jam in town. I'm neither a petrol-head or an environmentalist and it would surprise me if this is some sort of emissions scam but it sure seems that way. I hope to be advised otherwise.
Cheers
Neil

Jamo

Our fuel's not too good either! But I mix short trips with lots of long ones, so that's prbably why I haven't seen it happen yet.

ltc

The addition of a cetane boost additive is common practice here in the US for most diesel truck owners, given the low cetane rating for most US ULSD.

If left unchecked, low cetane diesel fuel will produce residue, similar to creosote or coking in a wood/coal stove, which will cause problems for emission devices and ultimately lead to a CEL.

Obviously, extended idling should be avoided, as is 'warming up the car' in the morning.

90S2C

Where does one find a diesel Cayenne in the US?

JSF101

good question, if you find out let me know

I want one but they haven't marketed them to US

at least, not yet??

Marc Gelefsky

In a VW dealer