vRS TDi DSG not engaging back in gear in Eco mode after coasting!

[Rabolt]

Hi i have a two week old vRS TDI DSG and the car would not go into gear after coasting in Eco mode! this happed around a round - a -roundabout and I had to stop and turn off the engine and re start to get it to move!

anyone els had the problem?

I am away on holiday at the moment and I will not get chance to take it back to the garage until another week.

[LewJo]

In the wrong situation that could be very dangerous. If I were you I'd either go to the nearest dealer or call Skoda Recovery.

Lewjo (Joseph)

[phsroberts]

I realise you need to get it fixed, but as an aside, there is very little benefit to putting your car in neutral while moving unless being towed. There is especially no benefit to fuel consumption in most cases.

Edited 31 October, 2013 by phsroberts

[phsroberts]

Oh and VRS...COASTING...ECO MODE???

Go and have a word with yourself, then get it put into sport mode.

[moley]

I have the seven speed DSG in the MkII Octavia so I'm not sure what ECO mode is? I only have D or S for travelling forwards.

[TudorM]

It's from the driving mode selection button. And in ECO, the DSG box has a coasting function. As in, when you take your foot off the accelerator, the box disengages and it just coasts, so you don't get engine braking and can travel further with less fuel (that's the theory anyway!).

[TheWanderer]

It could also be construed as not being in proper control of the vehicle, by the police if you have an accident.

 

I don't like coasting out of gear, it just doesn't feel right and leaves no feeling of control.

[Dodgy]

It could also be construed as not being in proper control of the vehicle, by the police if you have an accident.

 

 

Yes, yes of course it would.

[Orville]

Clearly this is a fault and should be reported to the Dealer, who should then investigate and report findings to SUK. It may just be a one-off glitch, or perhaps a fault with the vehicle in question, but it could also be a potential coding or component liability which requires a recall/fix.

 

There is nothing wrong with using Eco mode on a VRS DSG, but it shouldn't be a danger to use.

[The Plumber]

I tried all the modes while test driving a 150 and 184 DSG. With both cars I found that in eco, trying to accelerate quickly from slowing at a junction/roundabout resulted in the car appearing to get 'bogged down' and initially reluctant to pull away; OK in other modes mind.

 

 

TP

[J8mbo]

From VW website.

'While driving, as the driver’s foot is taken off the accelerator pedal the engine is declutched, allowing the vehicle to coast and roll over a longer distance. The momentum of the vehicle is used to save fuel with a foresighted driving style. When the brake, accelerator pedal or the gear selector lever is operated, the clutch is re-engaged and engine braking / drive takes effect. Coasting Function can be selected or deselected via the multifunction display settings. The gear selector lever is required to be in the D position to be functional. The coasting function is only available with direct shift gearbox (DSG) transmissions in selected models.'

quote name="TheWanderer" post="3485872" timestamp="1383213959"]It could also be construed as not being in proper control of the vehicle, by the police if you have an accident.

That's unlikely as it's a function of the vehicle by design.

[Neily03]

Weird as coasting wastes fuel as it's needs to stop the engine stalling, rolling along in gear uses no fuel at all......

[TudorM]

But you'll come to a stop much quicker. So I'm guessing it's been calculated that it is actually a fuel saving to coast with the clutches disengaged and use fuel to keep the engine running rather than the other way around.

[Thomasscatman]

Exact same thing happened to me 2 weeks ago. Out of a roundabout, had to stop on the sidewalk and start engine.

 

I supposed it could be a "one-off glitch" and thought I should just wait and see if it happened again, before I took it to the dealer.

But if others have experienced this, perhaps it should be followed up...

 

Although I hardly ever use the eco-mode now....

[Neily03]

But you'll come to a stop much quicker. So I'm guessing it's been calculated that it is actually a fuel saving to coast with the clutches disengaged and use fuel to keep the engine running rather than the other way around.

No it'll take longer to come to a stop coasting that it would using engine braking.

[TudorM]

Neily, that's exactly what I said. You stop faster with engine braking rather than coasting. It seems VAG engineers have calculated you still save fuel by coasting rather than in gear and engine braking.

[Sheldon.Cooper]

I've had this once (Only been in eco 3 times so not a great confidence factor).

 

costing to a round about, timed my approach so I could fit into a gap in traffic without braking, pressed the accelerator and naff all happened (box changed gear about 4 times but no drive between gear changes just lots of revs) then it eventually lept forward just as my gap was closing and I was about to do an emergency stop.

 

Haven't been in eco since.

[Anddenton]

Neily, that's exactly what I said. You stop faster with engine braking rather than coasting. It seems VAG engineers have calculated you still save fuel by coasting rather than in gear and engine braking.

 

Maybe on the flat but I would think the hills around my way would soon negate the saving.

[Orville]

Coasting in-gear creates mechanical drag, effectively slowing you down and thus requiring more throttle activation to keep pace with traffic or maintain speed. Depending on the engine map additional fuel may also be injected at higher than idle rpm. Coasting in-gear will always use more fuel.

 

Regarding braking distances they will remain identical for in-gear and out of gear coasts. Breaking distance is ultimately determined by adhesion of the tyres to the road, the speed you are travelling, and mass. Slam on the brakes as hard as possible so that ABS engages and both methods of coasting will result in the same stopping distance because both have identical grip levels. Prior to ABS engine breaking held potential benefs on loose surfaces, but ABS effectively removes any advantage.

 

Some argue that engine breaking prolongs the life of brake pads and disks, but it can equally be argued that it reduces clutch, gearbox and engine life.

 

My opinion is that Eco mode engaging coast on a DSG gearbox is a good idea. It just needs to work properly. The risk is that as these cars get older, what will happen if the car stalls out of gear? Driver will llikely lose servo assisted breaking and power assisted steering, and head straight into an accident.

Edited 31 October, 2013 by Orville

[TudorM]

That's simply not true. It's like stating that engine braking is useless while going downhill and you could just as well be out of gear. Everybody knows you can use engine braking while descending a slope. Try and do that out of gear and let me know how it goes... There is no coasting in-gear. Without accelerator input, that's called engine braking.

 

Also, in modern engines, if you leave the car in gear and take your foot off the accelerator the engine will use 0 fuel. Check your instant fuel usage on your maxi-dot.

[Orville]

That's simply not true. It's like stating that engine braking is useless while going downhill and you could just as well be out of gear. Everybody knows you can use engine braking while descending a slope. Try and do that out of gear and let me know how it goes... There is no coasting in-gear. Without accelerator input, that's called engine braking.

 

Also, in modern engines, if you leave the car in gear and take your foot off the accelerator the engine will use 0 fuel. Check your instant fuel usage on your maxi-dot.

You could simply use the brake pedal instead and save fuel at the same time. The brake will be doing what it is designed for whilst the engine will not. Don't forget that we are talking about DSG gearboxes running in Eco mode whilst coasting out of gear. It is not quite the same as engaging neutral on a manual, which takes time and thought.

 

Your second point is profoundly incorrect. Without fuel the engine will simply stall. Some fuel must ALWAYS be used to keep the DPF/CAT hot and fire the engine. Fuel/injector  pressue can drop to extremely low levels but as far as I am aware not zero.

Edited 31 October, 2013 by Orville

[TudorM]

Why would you use the brake pedal when you can use the engine braking? There are situations where it is highly advised, such going down steep hills. I thought this is common knowledge? It saves you from cooking your brakes... There's even road signs for that.

 

Your second point is profoundly incorrect. Without fuel the engine will simply stall. Some fuel must ALWAYS be used to keep it running.

 

Umm no, like I said, in gear and with no accelerator input a modern engine uses NO fuel. It uses the work generated by the forward motion, turning the wheels and all the way down to the drive-shaft to keep the engine running. Like I said, try it out in your own car and check your instant fuel usage display on maxi-dot.

Edited 31 October, 2013 by TudorM

[TheWanderer]

It is illegal to coast out of gear, I've just checked it.

[andyvee]

Did you come to a complete standstill before accelerating? Perhaps a dab on the brakes would reengage the gearbox?

[Orville]

If out-of-gear coasting is less efficient than in-gear coasting, why do VAG, BMW, Nissan ect use it within their Eco modes?

 

edit: Maybe found the answer here.

 

I think the general idea is that more fuel is used whilst coasting in-gear because mechanical drag slows the car down, thus requiring more energy to bring it back up to speed or to maintain speed, than would otherwise be required whilst coasting out of gear.

 

So technically more fuel is used whilst coasting out-of-gear than when in-gear, but even more fuel is needed to counteract the additional drag created by coasting in-gear, thus making coasting out-of-gear more efficient overall.

 

I also apologise to TudorM. Most modern cars can indeed cut off fuel entirely whilst coasting in-gear. Fuel is still required at low rpm's (~1400rpm or below), but at medium to high revs all fuel can indeed be cut. I am getting too old and my mechanical knowledge pre-dates this century.

Edited 31 October, 2013 by Orville