2021 Mark IV Octavia Combi Style TD85/2.0 M6F poor performance in 6th gear when cold

[Mul57]

Hi,

My 2021 Mark IV Octavia Combi Style TD85/2.0 116 BHP 6 Speed Manual struggles in 6th gear when the temperature is below about 4 degrees Celsius, causing an uncomfortable, jerky ride until the engine warms up. Is this common problem?

Thanks,

Mul57

[GreenlineIIEstate]

6th gear is purely a cruising gear I would think so what are you asking the car to do in that gear?

 

If you need to accelerate I feel a change down to a lower gear might help.

[MiniNinjaRob]

At what sort of speed?

[Mul57]

Thanks for the replies guys. I get up to about 90kmph before going into 6th gear and hit cruise control. It's my regular work commute on a pretty flat road and usually I have no issues. It's only when it's cold I have issues. 

[SurreyJohn]

That version has top speed (per brochure) of 133mph (215km/h), so you are cruising in 6th gear at about 40% of top speed.

 

Not sure what the gearing is, but I suspect when the engine is cold you are upsetting the emissions system which is trying to get the DPF upto temperature.  Possibly it is aware that with emissions system too cold to work fully, and avoid breaching tailpipe limits it is cutting fuel causing the jerking.

 

You probably need to change your driving style and not use 6th gear at so low a speed as 90km/h until engine is warmed through and emissions system is upto ideal temperature.

 

[MiniNinjaRob]

3 minutes ago, SurreyJohn said:

That version has top speed (per brochure) of 133mph (215km/h), so you are cruising in 6th gear at about 40% of top speed.

 

Not sure what the gearing is, but I suspect when the engine is cold you are upsetting the emissions system which is trying to get the DPF upto temperature.  Possibly it is aware that with emissions system too cold to work fully, and avoid breaching tailpipe limits it is cutting fuel causing the jerking.

 

You probably need to change your driving style and not use 6th gear at so low a speed as 90km/h until engine is warmed through and emissions system is upto ideal temperature.

 

 

I'd agree, thats only 55mph which is a bit low for 6th which is designed to be a motorway cruising gear really.  I'm guessing that is quite low RPM in a petrol and won't be in any sort of decent power band so it'll be labouring even when warmed up which isn't great for the engine anyhow.

[Mul57]

Thanks for the great explanation guys. Although it's my 4th Octavia it's the 1st I've had with 6 gears. I'll adjust my driving style accordingly.

[SkOmk4]

2 hours ago, Mul57 said:

it's the 1st I've had with 6 gears

Just curious: when you change to 6th gear at about 90kmph, what's the rpm?
If I correctly understand your signature (and you have the 2.0TDI 116bhp) you might expect the engine to be happy at low revs, but when not up to working temp - it's quite normal to under-perform.

[Mul57]

SkOmk4 thanks for the reply. Unfortunately no cold weather here this week to check performance. Just normal conditions. Change to 6th gear at about 90kmph at around 16000 rpm

[MiniNinjaRob]

I assume you mean 1600rpm!

1600 is a bit low to need to change up. 

[J.R.]

Not need but desire.

 

If you are driving economically and the conditions are correct there is no problem with changing up at 1600 rpm or less on a turbo-diesel.

 

I will drive in 6th gear in a camera controlled 50kph zone dependant on the gradient, wind, engine temp etc, around 1200 rpm, I will change down to increase speed. The annoying "change gear" indicator will sometimes want me to drop to 5th, other times not and its not usually agreeing with the feedback I am getting from the vehicle, on the flat with a warm engine & no headwind if it does it then I know a regen is in progress if I havn't already felt or heard the engine note changing.

[MiniNinjaRob]

23 minutes ago, J.R. said:

Not need but desire.

 

If you are driving economically and the conditions are correct there is no problem with changing up at 1600 rpm or less on a turbo-diesel.

 

I will drive in 6th gear in a camera controlled 50kph zone dependant on the gradient, wind, engine temp etc, around 1200 rpm, I will change down to increase speed. The annoying "change gear" indicator will sometimes want me to drop to 5th, other times not and its not usually agreeing with the feedback I am getting from the vehicle, on the flat with a warm engine & no headwind if it does it then I know a regen is in progress if I havn't already felt or heard the engine note changing.

You can “desire” however much you want but if the car doesn’t like it it will complain. Every car is geared differently and you need to drive to how the car is set up. 
For example I had an Astra Ecoflex and it had an eco 6sp gearbox and final drive which were completely different to the non ecoflex manual turbo diesel. The torque was increased and the final drive lengthened so you could cruise at a lower RPM at higher gears.  However this did mean it was much easier to stall when setting off as the torque wasn’t quite enough to overcome the long gearing from a standstill. Took a bit of getting used to compared to my previous diesels. 
 

If the OPs car is struggling at 1600rpm at cold then he needs to change up later until it’s warmed up. No amount of wanting to do differently will make any difference!!

 

Chugging around at low rpm all the time will also gunk up the EGR valves and other eco systems, as well as doing the turbo no good (especially on short journeys).  If you are getting a regen at low speeds/rpm then you need to run the car at some higher speeds more regularly or the engine will suffer. If you can’t do this then get the EGR and intakes cleaned regularly and change the oil a lot more often. 
 

I have never “experience” a regen as I’ve always done motorway or fast A road drives regularly in my turbo diesels. 
 

Thankfully no longer an issue now TDs are thankfully disappearing from the roads and BIK taxing favours petrol hybrids. 

[SkOmk4]

As you can deduce from my signature, I've been driving 2 diesel engines (for quite some time and mileage), older one manual-gearbox and newer one a dual-clutch automatic. Indeed, if you allow the automatic to change in Eco mode or even in Comfort mode it has a tendency to keep the engine at low-revs, unless better response is asked by driver via accelerator. So I've seen it up-shifting and falling to revs even below 1500 rpm, but on that engine it was not a real problem (enough power and great torque at low revs); and if it was needed the kick-down was quite fast...
On the manual gearbox and the lower-power engine it's a different story (in my case), the engine is not happy at all at low revs when cold (behavior/response and sound are different). The phenomenon that you describe @Mul57 is quite normal when the engine is cold, I wouldn't consider it a technical issue. Try to change to 6th gear at slightly higher speed, such that you fall closer to 2.000 rpm or even above - at least when the engine is cold.

[J.R.]

2 hours ago, MiniNinjaRob said:

You can “desire” however much you want but if the car doesn’t like it it will complain. Every car is geared differently and you need to drive to how the car is set up. 

 

I do thank you, without needing your education on the subject.

 

If the OPs car is struggling at 1600rpm at cold then he needs to change up later until it’s warmed up. No amount of wanting to do differently will make any difference!!

 

 If you are getting a regen at low speeds/rpm then you need to run the car at some higher speeds more regularly or the engine will suffer.

 

BS, a regen occurs when the conditions are correct, higher RPM and elevated exhaust temperature, if during a regen you cruise at low RPM in a higher (numeric) gear then the dash display will prompt a downchange when it would not normally.
 

I have never “experience” a regen as I’ve always done motorway or fast A road drives regularly in my turbo diesels. 
 

You will have experienced at least 2 per tankfull of fuel on a VAG EA189 engine with emissions fix, that you think you havn't shows that you are not as in tune with your engine as you are with philosophising about it.

You were (and still are) the person telling people what they need to do, I was simply pointing out that the OP had chosen to drive in 6th gear at 1600 rpm

Edited 20 March, 2022 by J.R.