The Curious Incident of the Stop/Start at the Roundabout

[Amarillo]

Occasionally I roll to a standstill with my foot gently on the brake, and just before I come to a standstill the Stop/Start kicks in and the engine cuts out, perhaps at 1 or 2 mph, perhaps slower. It is not a problem.

Yesterday I was coming up to a roundabout at low speed, slightly uphill. Just before coming to a stop the engine cut out. At exactly that same time I realised that a car which I thought was continuing around the roundabout was coming off, and I moved my foot from brake to accelerator. Whether or not the engine restarted as I released the brake I cannot recall with any degree of certainty, but what I am absolutely certain about is the van began to roll backwards before I could touch the accelerator. Instinctively I moved my foot back to the brake, stopped properly, with or without the engine running, before moving off.

What the driver immediately behind me thought of all this was probably lost in a stream of expletives directed at me.

 

[Perfectos]

Occasionally I roll to a standstill with my foot gently on the brake, and just before I come to a standstill the Stop/Start kicks in and the engine cuts out, perhaps at 1 or 2 mph, perhaps slower. It is not a problem.

Yesterday I was coming up to a roundabout at low speed, slightly uphill. Just before coming to a stop the engine cut out. At exactly that same time I realised that a car which I thought was continuing around the roundabout was coming off, and I moved my foot from brake to accelerator. Whether or not the engine restarted as I released the brake I cannot recall with any degree of certainty, but what I am absolutely certain about is the van began to roll backwards before I could touch the accelerator. Instinctively I moved my foot back to the brake, stopped properly, with or without the engine running, before moving off.

What the driver immediately behind me thought of all this was probably lost in a stream of expletives directed at me.

Hi Amarillo,

The very same thing has happened to me.

Slight incline approaching a T junction ( joining main road)
I was Slightly breaking to reduce speed to pull up behind a car waiting to pull out of the T junction, as I approached the car in front, engine cut out, then the Cali rolled back. I immediately Stamped on the brakes, before rolling into the car behind, who had pulled up behind me, (my work colleague). When at full stop I applied the hand break, lifted my foot off the brakes and the Cali started, I then approach the give way and drove away normally (car infront had obviously departed)

It was one of those momentary things where instinctively you take over to prevent an accident.

It was enough to make me swear, I was a little puzzled, as I dint think this could happen?

Next day at work I asked if my work colleague had seen me rolling back, he had as I nearly hit him !

Still do not know how this happened ?

 

[WelshGas]

Occasionally I roll to a standstill with my foot gently on the brake, and just before I come to a standstill the Stop/Start kicks in and the engine cuts out, perhaps at 1 or 2 mph, perhaps slower. It is not a problem.

Yesterday I was coming up to a roundabout at low speed, slightly uphill. Just before coming to a stop the engine cut out. At exactly that same time I realised that a car which I thought was continuing around the roundabout was coming off, and I moved my foot from brake to accelerator. Whether or not the engine restarted as I released the brake I cannot recall with any degree of certainty, but what I am absolutely certain about is the van began to roll backwards before I could touch the accelerator. Instinctively I moved my foot back to the brake, stopped properly, with or without the engine running, before moving off.

What the driver immediately behind me thought of all this was probably lost in a stream of expletives directed at me.

Hi Amarillo,

The very same thing has happened to me.

Slight incline approaching a T junction ( joining main road)
I was Slightly breaking to reduce speed to pull up behind a car waiting to pull out of the T junction, as I approached the car in front, engine cut out, then the Cali rolled back. I immediately Stamped on the brakes, before rolling into the car behind, who had pulled up behind me, (my work colleague). When at full stop I applied the hand break, lifted my foot off the brakes and the Cali started, I then approach the give way and drove away normally (car infront had obviously departed)

It was one of those momentary things where instinctively you take over to prevent an accident.

It was enough to make me swear, I was a little puzzled, as I dint think this could happen?

Next day at work I asked if my work colleague had seen me rolling back, he had as I nearly hit him !

Still do not know how this happened ?

When starting off on an incline Hill Hold Assist is engaged to prevent the vehicle rolling back whilst the drive is engaged.
The degree of Hill Hold Assist is dependant on two factors, the degree of Incline and the degree of braking force used when coming to a rest.

In both your cases you mentioned a “ slight incline “ and the fact that that you were using “ minimal braking “. I think therefore that the Hill Hold Assist was not activated.

What I find more worrying is that you both mentioned that the Stop/Start switched Off the Engine BEFORE you had come to a rest.
I have never had that on my T5.1. I can come to a Stop with minimal braking and control the Engine Stop by increasing the brake pressure, or not.
Personally, Stop/Start activating before the vehicle has physically stopped would mean a trip to the Dealer.
VW mention that Engine Stop only occurs at Standstill.

https://www.volkswagen.co.uk/technology/stop-start

 

[GrannyJen]

He was too busy studying his spreadsheet on how many stop-starts that night / average over a year / effect on fuel consumption to notice

 

[Bramco]

VW mention that Engine Stop only occurs at Standstill

That depends on how the sensors and software define standstill. We've certainly had occasions when the engine has stopped before the van has come to a complete standstill.

Also if you are not a binary driver (full on the accelerator or full on the brakes) then you will have noticed that gently approaching a junction where you may need to use hill hold means you need to press quite hard on the brake pedal as you come to a stop otherwise it won't have engaged and you'll roll back (unless your clutch control is as it was when you passed you test of course).

 

[2into1]

Yep, this is how it works in real life and a reminder of how stupid the system is on the auto (I give it 10 mins before the neigh sayers arrive to the contrary).
- Mine routinely stops whilst still moving slightly
- I’m often feathering the brake to try (usually failing) to prevent the auto stop engage, so the hill hold hasn’t engaged.
- I’m driving an auto, it’s in drive, so I expect based on 40 years driving experience it to hold me on its own on a modest incline (without any auto brakes).

I fail to understand why anyone could defend the auto start stop engaging in the situation Amarillo describes above. It is so far removed from how it works with a manual gearbox.

The only way to make it safe (if stupid) would be to share a sensor between the decision to stop the engine AND the decision to apply the hill hold, rather than rely on two sensors that have different parameters.

I’ve got the adapter gizmo ready to fit and I had been questioning whether it was the right thing to do, but this confirms it is exactly the right thing to do.

 

[JohnnyP]

When starting off on an incline Hill Hold Assist is engaged to prevent the vehicle rolling back whilst the drive is engaged.
The degree of Hill Hold Assist is dependant on two factors, the degree of Incline and the degree of braking force used when coming to a rest.

In both your cases you mentioned a “ slight incline “ and the fact that that you were using “ minimal braking “. I think therefore that the Hill Hold Assist was not activated.

What I find more worrying is that you both mentioned that the Stop/Start switched Off the Engine BEFORE you had come to a rest.
I have never had that on my T5.1. I can come to a Stop with minimal braking and control the Engine Stop by increasing the brake pressure, or not.
Personally, Stop/Start activating before the vehicle has physically stopped would mean a trip to the Dealer.
VW mention that Engine Stop only occurs at Standstill.

https://www.volkswagen.co.uk/technology/stop-start

When I first drove my T6 DSG back from the dealership after collecting I noticed the stop / start kicking in when the vehicle was still moving (2 maybe 3mph). This was distinctly different to my Euro 5 passat DSG which only cuts out when the vehicle is at a standstill.

I contacted the dealer immediately as I thought the van had a stop / start fault, the dealer new exactly what I was describing and confirmed that this was not a fault and was by design and new to the T6 DSG system. I suspect this is one of the ways to improve emissions / fuel efficiency figures for Euro 6 engines.

 

[soulstyledevon]

When I first drove my T6 DSG back from the dealership after collecting I noticed the stop / start kicking in when the vehicle was still moving (2 maybe 3mph). This was distinctly different to my Euro 5 passat DSG which only cuts out when the vehicle is at a standstill.

I contacted the dealer immediately as I thought the van had a stop / start fault, the dealer new exactly what I was describing and confirmed that this was not a fault and was by design and new to the T6 DSG system. I suspect this is one of the ways to improve emissions / fuel efficiency figures for Euro 6 engines.

Very worrying.
As stated previously I’ve had this happen numerous times now.
To be honest, i find it extremely dangerous.

 

[NZCol]

I don't like it at all which is why after test driving DSG i've ordered a manual

 

[Amarillo]

To be honest, i find it extremely dangerous.

"Extremely dangerous" might be overstating it, especially when compared to jumping out of an aircraft at 30,000 feet without a parachute. And I'm not sure mine cuts out at speeds above 1 mph. But, when combined with no Hill Hold Assistance on a slight incline, it is "extremely worrying".

 

[El Greco]

I have not had this issue. I am pretty sure mine cuts out when stationary. If you are moving without the engine running, I would assume the power steering has gone too

 

[kp64zl]

Hi @Amarillo -- you might be interested in this clinical trial of parachutes published in the British Medical Journal last Christmas

https://www.bmj.com/content/363/bmj.k5094

 

[hirsty]

Mine has never cut-out unless fully stopped .

As I normally have passengers I drive it quite steadily - rather than the binary style described above which I think makes it cut-out more readily.

YMMV.

 

[2into1]

I drive it quite steadily - rather than the binary style described above which I think makes it cut-out more readily.

Not helpful I’m afraid. The situation I described was as far from binary as a slipper wearing fairy straight from a relaxation course could manage.

 

[Borris]

I don't know about the technicalities here but if I remember, the first thing I do when driving either of our vehicles is to deactivate the silly stop/start thing. I find it so annoying. As far as I can see the only time it will save fuel is when the traffic is completely stationary in which case you can simply turn off the ignition. On all other occasions it will almost certainly cut out just as the vehicle in front is moving off.

 

[andyinluton]

- I’m driving an auto, it’s in drive, so I expect based on 40 years driving experience it to hold me on its own on a modest incline (without any auto brakes).

I bet most of those 40 years have been with a traditional slush box automatic with a fluid coupling.
Holding a DSG equipped van stationary on a hill by leaving it in drive rather than using the brakes is the quickest way of wrecking the clutch plates.

 

[s2bear]

Try reversing up an incline into a tight spot (not a euphemism), DSG lets go altogether and you just roll forwards with the engine still ON and your foot still planted on the gas.
Panic inducing when it first happens and pretty dangerous - pedestrians can walk across the front as they think THEY know where you’re going and YOU think YOU know where you’re going. I now keep the left foot ready for the brake.

This is also slightly irritating as, to the casual observer, you either park like Hyacinth Bucket (née Walton) or 17 1/2 year old Wayne from Romford, there’s no style in between. Apologies if anyone on here is actually all 3 of the latter at once.

Anyway, same same but different so slightly off topic, sorry.

My DSG S/S also cuts in JUST before stopping and will roll back before restarting.


Sent from my iPad using Tapatalk

 

[soulstyledevon]

Does look like a genuine problem.
I don’t think stop/start should activate until the vehicle has been stationary for at least 5 seconds.

As someone has posted already. Get the relay to disable it altogether

 

[2into1]

I bet most of those 40 years have been with a traditional slush box automatic with a fluid coupling.
Holding a DSG equipped van stationary on a hill by leaving it in drive rather than using the brakes is the quickest way of wrecking the clutch plates.

Why are you assuming I'm doing that? Folk on here are so quick to criticise other's driving. We are clearly talking about the moment between taking my foot off the brake and applying the accelerator.

 

[B J G]

I bet most of those 40 years have been with a traditional slush box automatic with a fluid coupling.
Holding a DSG equipped van stationary on a hill by leaving it in drive rather than using the brakes is the quickest way of wrecking the clutch plates.

When I raised this reversing stop/start motion with my Dealer's Technician he assured me that no clutch slipping action is made just computer controlled gear engagement.
Bit of a black art it seems. Doesn't inspire confidence. Former Eos with DSG behaved perfectly normally in reverse with no stop/start motions. I just put it down to the DSG being programmed for an empty van and not a laden Cali.

 

[Pips Dad]

I don't know about the technicalities here but if I remember, the first thing I do when driving either of our vehicles is to deactivate the silly stop/start thing. I find it so annoying. As far as I can see the only time it will save fuel is when the traffic is completely stationary in which case you can simply turn off the ignition. On all other occasions it will almost certainly cut out just as the vehicle in front is moving off.

Yes I totally agree with you Boris. I switch the damn thing off as soon as I get in the vehicle as the engine always cuts out just as you wish to set off making the fuel saving negligible. I would switch off if I thought I would be standing still for an unusually long time so can’t really see the point of it doing it for me.

 

[Erbster]

Yes I totally agree with you Boris. I switch the damn thing off as soon as I get in the vehicle as the engine always cuts out just as you wish to set off making the fuel saving negligible. I would switch off if I thought I would be standing still for an unusually long time so can’t really see the point of it doing it for me.

It’s purpose is not fuel saving, but to reduce emissions. It’s not intended to benefit us, but pedestrians (and pollution regulations).


https://caliventures364847572.wordpress.com/

 

[Keith Smith]

If this was such a world saving emissions reducing device they wouldn't give you a switch to turn it off! Perhaps when they are forced to do real world emissions tests it will get phased out.

 

[Pips Dad]

If this was such a world saving emissions reducing device they wouldn't give you a switch to turn it off! Perhaps when they are forced to do real world emissions tests it will get phased out.

Exactly!
Also the knock on effect of the thing constantly switching on and off in a busy town surely creates other long term problems with additional ware and tare creating more parts needing manufacture and more pollution.
One of the main problems is HGV’s and buses where the drivers sit in the cabs with the engines running whilst they have breaks etc. We’ve all seen this on a daily basis. It’s not the average motorist driving up to a road island and the engine cutting out just as you decide to move off! I don’t think this would save people being choked by fumes from already pretty clean modern diesels.

 

[Amarillo]

Exactly!
Also the knock on effect of the thing constantly switching on and off in a busy town surely creates other long term problems with additional ware and tare creating more parts needing manufacture and more pollution.
One of the main problems is HGV’s and buses where the drivers sit in the cabs with the engines running whilst they have breaks etc. We’ve all seen this on a daily basis. It’s not the average motorist driving up to a road island and the engine cutting out just as you decide to move off! I don’t think this would save people being choked by fumes from already pretty clean modern diesels.

What percentage of time is a car stationary on a typical London commute? 5%? 10%? 15%?

Whichever it is, stop/start has the potential to reduce pollution by up to that percentage.

I do not generally find it a problem, and adapt accordingly. But living in London I suppose it has become more routine for me than if I lived somewhere where the traffic flows faster and with fewer stops and starts.