[sh1513]

What you say about the Miller (or Atkinson) cycle is accurate, but Volkswagen are using a variation of this which they call the Budack cycle; here the intake valve closes early on the intake stroke instead of remaining open on the combustion stroke. Here's an explanation of both cycles:

If this is true then it doesn't explain the Kangaroo problem after all, I'm afraid.

Interesting video, glad I didn't go for a Tiguan with 27 mpg !!!

As for the kangaroo problem, the whole theory of it being to do with the Miller/Atkinson/Budack or whatever you want to call it cycle, is nobody has explained why it seems to disappear when the engine is up to normal operating temperature. If it is an issue with timing of the valves opening/closing, anti-stall and the turbo spinning, why does temperature have an effect :?: :?: :?: :?:

 

[ianchelt]

What you say about the Miller (or Atkinson) cycle is accurate, but Volkswagen are using a variation of this which they call the Budack cycle; here the intake valve closes early on the intake stroke instead of remaining open on the combustion stroke. Here's an explanation of both cycles:

If this is true then it doesn't explain the Kangaroo problem after all, I'm afraid.

Interesting video, glad I didn't go for a Tiguan with 27 mpg !!!

As for the kangaroo problem, the whole theory of it being to do with the Miller/Atkinson/Budack or whatever you want to call it cycle, is nobody has explained why it seems to disappear when the engine is up to normal operating temperature. If it is an issue with timing of the valves opening/closing, anti-stall and the turbo spinning, why does temperature have an effect :?: :?: :?: :?:

And... when I turn my stop/start option off just after starting the car, my Kangaroo issue disappears!.... I have tried this the last 3 mornings in a row using different methods.

For example, it was 5 degs C this morning. I started as normal... kangarooed down the road for 100 yards. Stopped. Switched off the engine. Restarted and immediately deactivated the stop/start option and continued my journey without a kangaroo in sight! I have done this 3 days in a row now and it has worked. Yesterday I deactivated the stop/start immediately after the first cold start in the morning, and again I didn't get any kangarooing.

I'm not saying I have found a solution here and I am sure others have tried this and it has not made any difference to their T-Rocs but so far it has worked for my T-Roc that's for sure. - Note: I have DSG. So not sure how this fits with the Miller cycle theory either. But hey I guess we are all entitled our theories.

T-Roc 1.5Tsi SE DSG

 

[Barnaclebob]

sh1513 Wrote "glad I didn't go for the Tiguan with 27 mpg".
The video is from a well known American YouTube channel and therein lies the problem. The American gallon is smaller than the Imperial gallon (approx 0.83) therefore 27 mpg (American) equates to 32.4 mpg here in the UK.
So really, not so bad for a big heavy car?

 

[niche]

What you say about the Miller (or Atkinson) cycle is accurate, but Volkswagen are using a variation of this which they call the Budack cycle; here the intake valve closes early on the intake stroke instead of remaining open on the combustion stroke. Here's an explanation of both cycles:

If this is true then it doesn't explain the Kangaroo problem after all, I'm afraid.

Interesting video, glad I didn't go for a Tiguan with 27 mpg !!!

As for the kangaroo problem, the whole theory of it being to do with the Miller/Atkinson/Budack or whatever you want to call it cycle, is nobody has explained why it seems to disappear when the engine is up to normal operating temperature. If it is an issue with timing of the valves opening/closing, anti-stall and the turbo spinning, why does temperature have an effect :?: :?: :?: :?:

And... when I turn my stop/start option off just after starting the car, my Kangaroo issue disappears!.... I have tried this the last 3 mornings in a row using different methods.

For example, it was 5 degs C this morning. I started as normal... kangarooed down the road for 100 yards. Stopped. Switched off the engine. Restarted and immediately deactivated the stop/start option and continued my journey without a kangaroo in sight! I have done this 3 days in a row now and it has worked. Yesterday I deactivated the stop/start immediately after the first cold start in the morning, and again I didn't get any kangarooing.

I'm not saying I have found a solution here and I am sure others have tried this and it has not made any difference to their T-Rocs but so far it has worked for my T-Roc that's for sure. - Note: I have DSG. So not sure how this fits with the Miller cycle theory either. But hey I guess we are all entitled our theories.

T-Roc 1.5Tsi SE DSG

It continues to surprise me just how many variations there are on this problem and how the "severity" is so variable too.

My Kangaroo was what I consider now to be "exrtreme" in that even once warmed up it was still very present at junctions / roundabouts etc - ie always present. The Stop/Start and fuel variants discussed here and also peppered throughout this mammoth post also made no difference.

Mine also was very very flat between 1 and 2,000 RPM -so much so it really struggled in 2nd up hills locally - but 1st was a bit too low - usually causing hiccups in even my adjusted driving.

It seems your variant is much less severe - I used to be jealous but then I Rejected it as a solution for mine didn't seem that close back in January - maybe now with the Skoda users experiencing some success that corner is about to be turned!

 

[sh1513]

sh1513 Wrote "glad I didn't go for the Tiguan with 27 mpg".
The video is from a well known American YouTube channel and therein lies the problem. The American gallon is smaller than the Imperial gallon (approx 0.83) therefore 27 mpg (American) equates to 32.4 mpg here in the UK.
So really, not so bad for a big heavy car?

It may be a heavy car, but I'd say that is still pretty rubbish mpg. Some of the latest Discovery Sport models can supposedly do 40+.

 

[Barnaclebob]

sh1513 Wrote that the latest Discovery Sport models can supposedly do 40+ but a check of their range indicates that Land Rover only fit the diesel engine in this range in the UK. Maybe I should have written "for a big heavy petrol engined car"?
Over in the USA very few people buy diesel cars - or ever did. VAG tried to counter this with their small efficient diesel engines and I'm sure they'd have been more successful if they'd been honest and upfront in the first place... We all know what happened - and they've paid the price for their deception!

 

[AV82]

As a previous owner of a Land Rover Discovery Sport with 2.0 litre diesel ingenium engine, it never came close to the mpg I get with my T Roc. Because manufacturers were allowed to print misleading fuel consumption figures based on laboratory tests, the figures for the DS were 40 town, 50 urban and 60 extra urban. I was lucky to get low forties with a very light right foot on extra urban runs. It took longer to warm up and the only redeeming feature was the 4WD capability, heated front screen (heritage from its Ford days) and flexibility with seven seats. The engine was flawed due to oil dilution in the sump by over fueling the diesel engine to try and ignite the DPF filter to burn the soot collected. This is a major problem for all DS diesel owners and the main reason I got rid of mine whilst still under warranty. The ingenium range of engines which are built at its Wolverhampton engine plant produce both petrol and diesel for the DS and have done for quite some time. The petrol modular engine is designed to allow a three cylinder, four cylinder or six cylinder block to be produced to fir a number of other JLR vehicles The engine plant is also producing electric motor drives for the move over to hybrid/electric vehicles as well as the change to more eco packages are required. I am happy with my T Roc but can see others are in a similar dilemma that I had when the car was not fit for purpose. Rejection is the answer for those that are suffering at no financial loss. The jury is still out on the actual cause of the "rooing". I have not had the misfortune to experience it but I believe it is related to when the first gear and second gear transition happens. With DSG this is covered by software on the manual model its not and because there are a high number of variables there it is difficult to produce a common fault or mode of operation. This should have been seen earlier and VW are lax in not solving this during testing in the field. Car buyers are not guinea pigs for the car manufacturers.

 

[Kietje]

The Miller cycle isn't used in the 110 kW in the T-Roc. Only the 96 kW 1.5 TSi comes with the Miller cycle, but you can't get that engine in a T-Roc.
My T-Roc has no kangaroo because I changed the responsiveness of the accelerator pedal.
There's a delay between putting the pedal down and the reaction from the throttle with caused the hik-ups. In my car i tweaked the delay with a vcds and/or an obdeleven device and no kangaroo. It's also usefull for other tweaks like taillights on with drl. And disable the start/stop system

 

[Newtroconthebloc]

The Miller cycle isn't used in the 110 kW in the T-Roc. Only the 96 kW 1.5 TSi comes with the Miller cycle, but you can't get that engine in a T-Roc.
My T-Roc has no kangaroo because I changed the responsiveness of the accelerator pedal.
There's a delay between putting the pedal down and the reaction from the throttle with caused the hik-ups. In my car i tweaked the delay with a vcds and/or an obdeleven device and no kangaroo. It's also usefull for other tweaks like taillights on with drl. And disable the start/stop system

Ummm
That's put the cat amongst the pigeons !

 

[Impala]

I think that delay between pedal and throttle response is one of the fuel economy measures designed to filter out small but unnecessary pedal movements. It does make the car seem unresponsive at times, unless you press the pedal down further/harder.

I think Sport driving mode reduces that delay to provide a sportier, more responsive drive, but many with the kangaroo have tried Sport mode and reported that it didn't help stop the Roo. It seems that different people are reporting different actions that help in their own situation, which might suggest the problem is due to a combination of several factors.

 

[sh1513]

My T-Roc has no kangaroo because I changed the responsiveness of the accelerator pedal.
There's a delay between putting the pedal down and the reaction from the throttle with caused the hik-ups. In my car i tweaked the delay with a vcds and/or an obdeleven device and no kangaroo. It's also usefull for other tweaks like taillights on with drl. And disable the start/stop system

Do you think you could pass this on to the VW techs? Because they don't seem to have a clue what they are doing!

 

[Musicegbdf]

I know some people say they cannot feel much difference . This can be due to the fact modern cars sense the difference . In the S3 if you put 95 Ron in the car it will work ok as it de tunes itself . In a classic car the differences are more obvious . Mine was originally designed for 5 star leaded .

Sorry going slightly off topic here .

 

[ianchelt]

Interestingly... (or not). Mine doesn't Kangaroo whilst I am reversing down the road! Now there's a thought for you engineering boffins! ...

Oh! and my friendly contact in the VW UK Executive Office told me today that a software release is "imminent". Yea right!!! But we can hope!

Keep the faith folks :roll:

 

[Musicegbdf]

Haha , did the contact also say brexit will be sorted before 22nd May .
Maybe that is the VAG game plan , wait till brexit and then refuse to help non Europeans ...

 

[T Roo]

I know some people say they cannot feel much difference . This can be due to the fact modern cars sense the difference . In the S3 if you put 95 Ron in the car it will work ok as it de tunes itself . In a classic car the differences are more obvious . Mine was originally designed for 5 star leaded .

Sorry going slightly off topic here .

Is it possible that those WITHOUT the dreaded roo are filling up with RON 95 premium unleaded and those using super unleaded RON 98/99, ARE rooing because the higher octane requires greater compression to ignite?

When pulling away and the inlet valve opens to increase capacity, is compression lost momentarily because the higher octane fuel needs more pressure to ignite and the T-Roc does not have that kind of high performance engine?

Oh, if only it is this simple

 

[Musicegbdf]

Off with daughter for her test drive of 1.5 TRoc tomorrow .
I will ask about lead time a Roo and see what they say . Am sure there will be a cow poo answer !

 

[Musicegbdf]

Ok daughter likes , but wants manual.
Apparently 31 week wait !!! Crazy , but maybe they will sort the Roo .
One dealer said they had heard about it , but never had one back . Another dealer said it is only on DSG cars ( as we wanted a manual ) . Yeah right in both cases .
Dealer trying to source one for us from another dealers stock .

 

[Manxman]

Ok daughter likes , but wants manual.
Apparently 31 week wait !!! Crazy , but maybe they will sort the Roo .
One dealer said they had heard about it , but never had one back . Another dealer said it is only on DSG cars ( as we wanted a manual ) . Yeah right in both cases .
Dealer trying to source one for us from another dealers stock .

Don't have any first hand experience yet Musicegbdf but the impression I had gained on this forum is that the roo almost (but not exclusively) always visits the manual transmission cars, not the DSG? I'm sure someone more experienced on the phenomenon will put us both right though!

 

[T Roo]

The roo predominantly affects the manual 1.5 tsi evo, but not all of them. The roo is less apparent in the DSG although it has been suggested the DSG might be masking it.

No-one, not even VW, knows why only some cars are affected and no-one knows why it is occurring at all. There is talk of a fix but no timescale for its release. Some T-Rocs have been tiggering for over a year. If you buy a new one, there is no assurance whether it will, or will not, pogo.

Skoda, another marque in the V.A.G. Group, are talking about an imminent fix but VW, Audi and SEAT are keeping mum.

Aside from the roo, the T-Roc is a good car and it's infuriating that its reputation is being spoiled. It's a £20-40k gamble. Good luck.

 

[Musicegbdf]

My point was I know from this very forum , (which has been fantastic by the way) and should not be surprised that the sales people try to play down the issue.