My car is an automatic and I have noticed of late that the revs have started to spike particularly, but not exclusively, when on a downward gradient.  Typically when going downhill I will remove my foot from the throttle to allow the car to coast but it will suddenly move from ‘D’ to another lower gear, the revs will spike by about 1K - 1.5K for a few seconds before dying down again.  I would expect that as it has moved from ‘D’ to a lower gear then the revs would spike coupled with deceleration as would be the norm in a manual, but in my case there is no deceleration just a spike in the revs.  I can only describe it as akin to keeping my foot on the throttle for a couple of seconds whilst I move the car into neutral. Coupled to this, when starting from cold the car revs quite high for about 10 seconds before dropping down to tick-over revs. Even when the car has been driven and thoroughly warmed then left for an hour or so in relatively warm temperatures it still revs high on the next start up but not quite so high or for so long. I would have thought the electronics would have managed this better.  I have previously owned a VW Golf with the same type of auto gearbox but never suffered these issues with it.  I am currently out of the UK and so the car is not being asked to perform in some of the excessively low temperatures being experienced in the UK at the moment.  On a long run I am only getting about 44 mpg which I expected to be better and wondered if the excessive revving (engine fault?) is in any way responsible or is 44mpg par for the 1.5L petrol engine on a run?

So is it showing D and not D7 on the dash, so shifter in D & actually coasting / 'coasting' enabled. 

Then engaging a lower gear rather than letting the car run away on a decline without the gear engaged?   Doing the job as it was designed / engineered to do.   ? Did the Golf have a 7 speed Wet clutch Dq381, or a DQ200 7 speed twin dry clutch DSG.  What year of Golf was it and what engine,?

Edited 24 January, 20233 yr by toot

1 hour ago, Ballast said:

is 44mpg par for the 1.5L petrol engine on a run?

 

Depends on your driving style and how loaded the car is - but it's probably not far off the mark for 'average real-world driving consumption'.

Thanks Yogi, My car would typically have two adults and a medium dog with no luggage doing a trip of about 60 miles on undulating roads at about a constant 65 mph in very light traffic.  If that’s what I can expect then thats fine with me.

3 hours ago, toot said:

So is it showing D and not D7 on the dash, so shifter in D & actually coasting / 'coasting' enabled. 

Then engaging a lower gear rather than letting the car run away on a decline without the gear engaged?   Doing the job as it was designed / engineered to do.   ? Did the Golf have a 7 speed Wet clutch Dq381, or a DQ200 7 speed twin dry clutch DSG.  What year of Golf was it and what engine,?

Hi Toot,  Thanks for your reply.  I probably did not explain myself correctly.  Yes the car is coasting but when it drops into the lower gear, there is no retardation, the car just continues to coast although the dash shows it has gone from D to a lower gear.  If you didn’t see the rev counter jump and engine note rise you would be unaware that anything had happened, it just continues as before.

I am not technically minded with the gearbox but I do know that the Golf was an 05, 2L diesel and had a twin clutch DSG.  I appreciate this car was much older that my present car and hence my query, as with the modern, smaller turbo charged engines I am unsure how they are supposed to act/react.

So really a very different DSG then and 6 speed and not an engine with Cylinder Deactivation like a 1.5 TSI ACT. 

Small capacity turbo engine that can run on 2 cylinders and has engine and DSG management to give low emissions that should mean good economy.

But then the same engine in a smaller Fabia, Scala, Kamiq is moving a Kodiaq. 

 

 

 

Edited 24 January, 20233 yr by toot

It is what it is.  It’s still more economical than my 3L diesel Jeep so I’m not complaining, just wondered if I should be getting more

57 minutes ago, Ballast said:

Hi Toot,  Thanks for your reply.  I probably did not explain myself correctly.  Yes the car is coasting but when it drops into the lower gear, there is no retardation, the car just continues to coast although the dash shows it has gone from D to a lower gear.  If you didn’t see the rev counter jump and engine note rise you would be unaware that anything had happened, it just continues as before.

I am not technically minded with the gearbox but I do know that the Golf was an 05, 2L diesel and had a twin clutch DSG.  I appreciate this car was much older that my present car and hence my query, as with the modern, smaller turbo charged engines I am unsure how they are supposed to act/react.

Strange it going from coasting to a low gear, mine only does this if you touch the brake pedal and it drops down a gear to provide engine braking.

Only thing it might be is if your battery is low the car is clever enough to engage a gear so the battery charges on the overrun.

Thanks Kenny,

The battery should be ok as it is not usually used for short runs and I am at present in an area where the temperatures are relatively mild so it isn’t working too hard to start up in the mornings.  It is due for service at the end of March so guess I will get them to look at it then.  Thanks again.

10 hours ago, Yogi-Bear said:

 

Depends on your driving style and how loaded the car is - but it's probably not far off the mark for 'average real-world driving consumption'.

 

I can tell you from someone who drives like an old man in a hat, that you're doing very well to get 44mpg at this time of the year out of a 1.5tsi Kodiaq DSG. 

9 hours ago, kodiaqsportline said:

you're doing very well to get 44mpg at this time of the year out of a 1.5tsi Kodiaq DSG

 

Never had a 1.5... but I used to get 40mpg+ out of my 1.4 Kodiaq all year round. I'm currently getting 30+ mpg out of the vRS on motorway trips - it too will do 40+ mpg in the summer. I'm conveniently ignoring the fact that for the last 10 days or so I've been lucky to get near 20mpg on 2-3 mile trips round town!

 

But yes, I drive like an old fart 😎.

 

(p.s. the OP did say 60 mile trips @ 65mph in light traffic and somewhere warmer than the UK...)

 

I own a 12m old 1.5tsi dsg too. 44mpg right now is incredible - that’s what I get in the summer on a good day.

 

re downhill behaviour I don’t expect it to decelerate like a diesel might. Mine does shift to lower gears but doesn’t decelerate dramatically (I see it as a ‘not letting the car run away’ sort of approach they seem to have put in place. I also own a 3cyl small diesel car - the compression on the diesel and just general characteristics make it an entirely different drive. The diesel is manual but unless the gas pedal is pressed 8/10 times you are going to slow down if you drop a gear on a hill.
 

Re distinctly high revs. I just went out to start mine up in the cold. It’s 1°, and the engine hasn’t been run today. Ran at about 1300 revs for 20 seconds, then dropped down to about 1100 before I switched it off. I expect probably another 20 seconds before it dropped back down to the normal idle. Is that what your was doing?

RPM cold or hot start as to be expected with a TSI with a GPF, even pre GPF TSI's.  Higher for 40 seconds or so then a drop.

The issue as the GPF cars get a bit older, do more short cold start trips is the GPF keeps the RPM high for longer.

Not handy on a cold / icy start off from someplace where you might normally just go off ticking over and now you need to be touching the brakes.

(That is for the future, but is already happening with some 2018 on 1.0 TSI Fabia mk3.)

Thanks Toot

2 hours ago, Doombar said:

 

I own a 12m old 1.5tsi dsg too. 44mpg right now is incredible - that’s what I get in the summer on a good day.

 

re downhill behaviour I don’t expect it to decelerate like a diesel might. Mine does shift to lower gears but doesn’t decelerate dramatically (I see it as a ‘not letting the car run away’ sort of approach they seem to have put in place. I also own a 3cyl small diesel car - the compression on the diesel and just general characteristics make it an entirely different drive. The diesel is manual but unless the gas pedal is pressed 8/10 times you are going to slow down if you drop a gear on a hill.
 

Re distinctly high revs. I just went out to start mine up in the cold. It’s 1°, and the engine hasn’t been run today. Ran at about 1300 revs for 20 seconds, then dropped down to about 1100 before I switched it off. I expect probably another 20 seconds before it dropped back down to the normal idle. Is that what your was doing?

 

From the replies I am getting it would appear that the revving/MPG and ACC issues I have highlighted all seem to be quirks of  the modern car (my last one was 6 years old when I let it go).  It has put my mind at rest if nothing else, so thank you all

2 hours ago, Doombar said:

 

I own a 12m old 1.5tsi dsg too. 44mpg right now is incredible - that’s what I get in the summer on a good day.

 

re downhill behaviour I don’t expect it to decelerate like a diesel might. Mine does shift to lower gears but doesn’t decelerate dramatically (I see it as a ‘not letting the car run away’ sort of approach they seem to have put in place. I also own a 3cyl small diesel car - the compression on the diesel and just general characteristics make it an entirely different drive. The diesel is manual but unless the gas pedal is pressed 8/10 times you are going to slow down if you drop a gear on a hill.
 

Re distinctly high revs. I just went out to start mine up in the cold. It’s 1°, and the engine hasn’t been run today. Ran at about 1300 revs for 20 seconds, then dropped down to about 1100 before I switched it off. I expect probably another 20 seconds before it dropped back down to the normal idle. Is that what your was doing?

 

Where I am at the moment, the cold start in the morning is taking place temps of, on average 12/14 degrees, so not a cold cold start but it is revving to about 2k before dropping back.  I our daytime temps are high teens low 20s so I guess my fuel consumption would equate to a reasonable day back in the UK. 

11 hours ago, kodiaqsportline said:

 

I can tell you from someone who drives like an old man in a hat, that you're doing very well to get 44mpg at this time of the year out of a 1.5tsi Kodiaq DSG. 

You could be describing my driving style!!!

@BallastWhen i say 'Cold Start' i do not mean Winter, around freezing.  It is any starting of an engine that has sat and the coolant / oil so the engine is at the ambient temp, then short drives.  In the teens degree Celsius the petrol engines might still start at a higher RPM. There is the Cartalytic converter as well as the GPF now that need getting to an efficient operating temp ASAP. 

 

There are even excuses made for rough running with some engines because that supposedly do not meet what ever the Engine Management requires. 

(These Euro 6 1.2 TSI were discontinue and replaced by 1.0 TSI's and with GPF's, but te same old is sometimes being given as the reason for a rough running new TSI.)

http://briskoda.net/forums/topic/504258-a-tsb-from-skoda-on-cold-start-behaviour-with-12-tsis-something-that-dealership-employees-should-be-able-to-eplain-to-customers

 

1 hour ago, Ballast said:

Where I am at the moment, the cold start in the morning is taking place temps of, on average 12/14 degrees, so not a cold cold start but it is revving to about 2k before dropping back.  I our daytime temps are high teens low 20s so I guess my fuel consumption would equate to a reasonable day back in the UK. 

2k revs sounds really high to me - and must make plenty of noise frankly as 1300 revs is hardly quiet!
 

What does your car need 700rpm more than my car for even on a cold day?! I don’t think I’ve ever owned a car that starts in need of 2000 revs in over 20 years of driving so if mine were behaving like that I would have it checked, especially if it wasn’t doing that before, and it’s a new behaviour.
 

Getting it checked might probably be a bit of a painful process if there is no engine management fault code light on that can easily be reviewed…

 

I imagine there are quite a few things this could be. For example I once had a car where the idle erratically became higher and it was a problem with the sensor in the accelerator pedal. Super quick (and cheap) fix,  but the nature of the fault was such that the car thought it was my foot on the pedal so no engine fault code. I had another car where the previous owner had undersized the battery when replacing it - that caused all sorts of weird things to occur…). Not suggesting these are your problems here though).

 

If you do end up taking it to a mechanic, please report back what they say, I’d be very interested.

On 25/01/2023 at 12:09, toot said:

@BallastWhen i say 'Cold Start' i do not mean Winter, around freezing.  It is any starting of an engine that has sat and the coolant / oil so the engine is at the ambient temp, then short drives.  In the teens degree Celsius the petrol engines might still start at a higher RPM. There is the Cartalytic converter as well as the GPF now that need getting to an efficient operating temp ASAP. 

 

There are even excuses made for rough running with some engines because that supposedly do not meet what ever the Engine Management requires. 

(These Euro 6 1.2 TSI were discontinue and replaced by 1.0 TSI's and with GPF's, but te same old is sometimes being given as the reason for a rough running new TSI.)

http://briskoda.net/forums/topic/504258-a-tsb-from-skoda-on-cold-start-behaviour-with-12-tsis-something-that-dealership-employees-should-be-able-to-eplain-to-customers

 

 

Thank you.  That explains a couple of other matters I was wondering about

On 25/01/2023 at 12:55, Doombar said:

2k revs sounds really high to me - and must make plenty of noise frankly as 1300 revs is hardly quiet!
 

What does your car need 700rpm more than my car for even on a cold day?! I don’t think I’ve ever owned a car that starts in need of 2000 revs in over 20 years of driving so if mine were behaving like that I would have it checked, especially if it wasn’t doing that before, and it’s a new behaviour.
 

Getting it checked might probably be a bit of a painful process if there is no engine management fault code light on that can easily be reviewed…

 

I imagine there are quite a few things this could be. For example I once had a car where the idle erratically became higher and it was a problem with the sensor in the accelerator pedal. Super quick (and cheap) fix,  but the nature of the fault was such that the car thought it was my foot on the pedal so no engine fault code. I had another car where the previous owner had undersized the battery when replacing it - that caused all sorts of weird things to occur…). Not suggesting these are your problems here though).

 

If you do end up taking it to a mechanic, please report back what they say, I’d be very interested.

 

Thank you.  I will get it checked out when I return to the UK.  I have driven many different new cars cars over the years (firms cars/hire cars - not mine) and always found the engine management system seems to keep a pretty good check on keeping the engine revs at a fairly constant rate no matter what, but it doesn’t seem the case here but I do have limited knowledge of the modern small turbo charged engine and their quirks, hence my queries.  For peace of mind I will take it to the main deal as it is under 12 months old with just over 11K on the clock so hopefully if there is an issue it should come under the warranty.