I think this is true on many recent petrol cars in varying implementations - it's to light up the catalyst. The colder it is the longer it is required for. Whilst the catalyst isn't up to temperature your car emits way more harmful emissions. Even my previous 2014 mkII Superb with the old EA111 1.4tsi petrol revved up to 1100 rpm for a while when cold.

The evo 2 version of the 1.0 and 1.5 tsi has been used for a couple of years in the Kamiq/ Scala etc - this was first rolled out in the VW T-Roc. "This is an advanced efficiency engine and one of the improvements was a new catalytic converter that reaches its operating temperature more quickly."

Edited 24 March, 20251 yr by bigjohn

Hi bigjohn, if that's true, and I don't doubt it, then it looks like I'll have to pollute the air waiting for the revs to drop in order not to pollute the air.

Thanks for your input-all of you- there's certainly a wealth of knowledge on this forum.

What @Bigjohn says is pretty much spot on. Manufacturers are under pressure to conform to bureaucratic standards with little regard to the real world. So while I like the 50mpg on a run performance from the engine I have to live with little odd quirks like revving to 1400 rpm when cold and not quite understanding that torque demand on a fast A road is going to be very variable and that maybe not deploying ACT so quickly might be helpful to making smooth progress. (I'm still experimenting with this and I might start to use the flappy paddles and sport mode a bit more.)

@Nosheds I am well aware the engine temperature matters and if cold started and run. It cold start in cold weather is t cold started in warner weather. And as for cold starting from freezing and getting the engine oil to 50 degrees C and stopping and 20 minutes later out in freezing weather that can be another cold start. Very different cold start on warm day then stop and later start. I was really just trying to know if the 40 seconds was really cold weather and cold engine. When I was checking cars and tick overs and time taken I filmed and timed and noted ambient temp. Even measured oil temperature. Which when cold is not lower than the ambient temperature.

Hi, yes- a minute from completely cold.

A bit more on this, car (the Skoda) was at 10C in the garage yesterday.

Reversed out to clean it.

On starting the revs were increased to around 1300 rpm for maybe 20 seconds, then they dropped to around 1100 rpm for a further 20 seconds. After that they settled to idle at about 800 rpm.

After cleaning re-started engine, idle revs at 800 rpm almost instantly.

Went for a little dry-out drive and then put the (shiny!) car away.

Hi, thanks for that. It seems that they all have slightly different idle characteristics when cold; mine's always 1400 from a minute down depending on temperature. Maybe the dealer can tweak it down a bit.

On 27/03/2025 at 10:47, Nosheds said:

Hi, thanks for that. It seems that they all have slightly different idle characteristics when cold; mine's always 1400 from a minute down depending on temperature. Maybe the dealer can tweak it down a bit.

The breather on top of the engine is a common fault, possibly causing an air leak effectively altering the air fuel ratio

Thanks, I'll take a look.