exhaust smoke when the petrol engine starts.

[Ali Collins]

Hi All I was sitting stationary at the traffic lights and my indications were that only the electric motor was running. I felt the petrol engine cut in and I noticed plumes of smoke coming from my car, this disappeared when we started moving so the next time I was held stationary with only the electric motor running I paid special attention to the exhaust output when the petrol one cut in and sure as eggs are eggs the billowing clouds of smoke appeared. So is this normal or should I be worried. Has anyone else got this problem or had it in the past? I would be grateful for any input. Regards Peter.

[colin79666]

What colour was the smoke and was the engine cold?

[Paul Brooksbank]

At this time of year it's more likely to be steam rather than smoke. As the Lexus engine doesn't run much above 1500 rpm, the exhaust system takes a long time to heat up. If you need a glaring example, take a look at a condensing boiler flue on start up, you get clouds of steam on a cold day, then later it isn't as noticeable. 

[stormchaser]

More information needed and a video if possible?
It’s probably just fuel vapour with a cold engine. These engines aren’t prone to smoking.


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[scudney]

Or just steam from condensation 

[Britprius]

When sitting on a cold day with the engine off in electric mode the exhaust system will loose it's heat. When the engine starts as you pull away the exhaust gasses condense in the cold exhaust to form steam.
It is the steam you can see. For every gallon of petrol you use 8 gallons of water are produced out of the exhaust.

John.

[Peter Collins]

The engine was cold so I assume that it is as your members inform me and is steam. Thanks everyone for your input it is most appreciates. Regards Peter.