Stop/starting

[Isocrem]

I've been getting a bit peed off with my Stop/Start (I don't think I'm the only one). One of the things that was confusing me about it was it's ability to stop then start immediately, even though conditions seemed to be perfect for a nice little stop period! I think I've worked out one of the reasons why (Petrol Manual, by the way).

 

On coming to a stop at lights(for instance) I'll brake down, with a release of the pressure on the brake pedal before coming to a stop..if I then decide to put the handbrake on I'm in the habit of firming up the brake pressure, applying the handbrake, into neutral then release the clutch and brake pedal. It seems that the firming up of the brake pedal, then release after applying the handbrake kicks the engine back in (I've tried this without using handbrake and the engine kicks back in when the brake is released, which is fair enough). However, I think it's very odd it does this if the car is in neutral and the handbrake is on. Perhaps my deduction is wrong?..

 

 

 

 

[glosrich]

It'll also restart if the interior temp set on the climate isnt achievable with the engine off, or if you move the steering wheel.

[Gabbo]

This is a safety feature for StopStart in case you are holding the vehicle stationary with the brake pedal.

It monitors the brake vacuum pressure & when the reservoir nears empty it restarts the engine so that the vacuum pump can refill the reservoir.

 

This is to prevent a condition where you attempt a fast start from standstill but have to make an immediate emergency stop only to find you have no brake pressure left.

 

 

However, unless you are really pumping or pressing the brake hard when the engine is already stopped, you shouldnt have a with losing brake pressure.

Maybe you have a small leak in the system?

[Isocrem]

This is a safety feature for StopStart in case you are holding the vehicle stationary with the brake pedal.

It monitors the brake vacuum pressure & when the reservoir nears empty it restarts the engine so that the vacuum pump can refill the reservoir.

 

This is to prevent a condition where you attempt a fast start from standstill but have to make an immediate emergency stop only to find you have no brake pressure left.

 

 

However, unless you are really pumping or pressing the brake hard when the engine is already stopped, you shouldnt have a with losing brake pressure.

Maybe you have a small leak in the system?

 

That makes sense in terms of holding the car on a hill; release brake, engine starts, hill hold kicks in for a few seconds, then off..

 

I'm not putting massive pressure on the brakes before applying the handbrake. I was taught to firm up the foot brake before putting the handbrake on to set the brakes further and putting less strain on the handbrake  and it's a habit I've stuck to (for right or wrong). Maybe it's not necessary on vehicles these days? You may be right in that a sensor might be picking up a loss of brake pressure after firming the brake pedal. It's going to the dealers next week to have a door pillar rattle looked at, so I might mention it.

[Isocrem]

This is a safety feature for StopStart in case you are holding the vehicle stationary with the brake pedal.

It monitors the brake vacuum pressure & when the reservoir nears empty it restarts the engine so that the vacuum pump can refill the reservoir.

 

This is to prevent a condition where you attempt a fast start from standstill but have to make an immediate emergency stop only to find you have no brake pressure left.

 

 

However, unless you are really pumping or pressing the brake hard when the engine is already stopped, you shouldnt have a with losing brake pressure.

Maybe you have a small leak in the system?

 

I think you are correct, Gabbo. I just took the car to the shops. Stopped at lights with normal braking, handbrake on, neutral - engine stops. Whilst still sitting at the lights and with handbrake on I pushed down on the brake pedal and as soon as it was released the engine sparked up. A case of adjusting style to suit the technology, I think!

[Neily03]

I was taught to firm up the foot brake before putting the handbrake on to set the brakes further and putting less strain on the handbrake 

 

Eh??  All you're doing is using up the vacuum, nothing more.

[Isocrem]

Eh??  All you're doing is using up the vacuum, nothing more.

 

I'm no expert on car mechanics, but as far as I'm aware the foot brake isn't an on/off switch and the brakes progress as the pedal is pushed in (until they reach maximum pressure) When bringing the car to a stop the footbrake is generally eased off at low speed for a smooth stop, until the car comes to a halt and the foot pedal pressure is light (unless gradient demands otherwise). Surely pushing down the brake pedal a little more after coming to a stop will 'firm' up the brake pressure.

Edited 30 November, 2016 by Isocrem

[Neily03]

I'm no expert on car mechanics, but as far as I'm aware the foot brake isn't an on/off switch and the brakes progress as the pedal is pushed in (until they reach maximum pressure) When bringing the car to a stop the footbrake is generally eased off at low speed for a smooth stop, until the car comes to a halt and the foot pedal pressure is light (unless gradient demands otherwise). Surely pushing down the brake pedal a little more after coming to a stop will 'firm' up the brake pressure.

 

Brakes are only applied while the pedal is pressed, so no matter how many time you press the pedal once you stop as soon as you release the pedal the brakes release.  Other than the handbrake of course which is a separate cable operated system.

[Isocrem]

Brakes are only applied while the pedal is pressed, so no matter how many time you press the pedal once you stop as soon as you release the pedal the brakes release.  Other than the handbrake of course which is a separate cable operated system.

 

Yes, I understand that. Sorry, we must be on crossed purposes, because I'm not sure how that relates to the Post? I'm not sure I mentioned about pressing the brake pedal more times, just the pressure of the application. The perils of internet communication!

[gregoir]

My passenger said my starter motor will be prematurely worn out with the stop/start usage. Surely a special mechanism or design is used ? Any info on that ?

[Isocrem]

My passenger said my starter motor will be prematurely worn out with the stop/start usage. Surely a special mechanism or design is used ? Any info on that ?

 

As I understand it the whole system is made more robust for the many more times the engine will start and stop during it's lifetime. However, how far do you trust information from car manufacturers? One thing I do know is that the last car battery I bought cost £100. If and when I replace the one in this car, it will be double that at least. I think the concept behind start/stop is good, but the application at present (in this car) is a little dubious. I'm sure things will move on technology wise, but I hope not at the financial cost of early stage users.

[Gabbo]

My passenger said my starter motor will be prematurely worn out with the stop/start usage. Surely a special mechanism or design is used ? Any info on that ?

 

I'd imagine the thousands of engineers working in the automotive industry might have thought of that when the feature was introduced...

 

In fact for most people your driving style is no where the worst case.

Even before StopStart concider the delivery driver or postman who would regularly stop and start their van/car on the rounds.

 

Even with StopStart a normal driver (to & from work each day) will probably only use the starter motor 10% of the maximum useage which the system is designed for.

[Flying]

The fact that it defaults to stop/start mode is what I find annoying.  Apparently the only reason one cannot change that default is that stop/start was necessary to meet the EU emissions figures but we know the VAG group found other ways of doing that until they were rumbled.

[gregoir]

I've had several starter motors and associated mechanisms wearing out over my 48 years of driving. The stop starting is incredibly frequent in heavy traffic.I fondly imagined there was something special to mitigate the continuous clashing of metal parts.

[SuperbTWM]

Surely a special mechanism or design is used ? 

 Yes, there is a button that turns the stop/start off.

 

Stop start is a next to pointless invention that came about because a large portion of the EU driving test cycle is with the car stationary so with the invention of stop/start all the manufacturers were able to reduce their emission dramatically. Once they revise this test to a more real world solution stop/start will have less of an effect 

Edited 30 November, 2016 by SuperbTWM

[Isocrem]

VAG will be fitting a Petrol particulate filter from 2017. I don't know if this will replace stop/start. 

[pist0nbr0ke]

Stop/start can be disabled with VCDS. I've done mine.

[Gabbo]

Stop start is a next to pointless invention that came about because a large portion of the EU driving test cycle is with the car stationary so with the invention of stop/start all the manufacturers were able to reduce their emission dramatically. Once they revise this test to a more real world solution stop/start will have less of an effect 

 

Its not completely pointless, it does save you a couple of hundred pounds in road tax each year  even it it has a negligable effect on the environment in the real world.

Edited 30 November, 2016 by Gabbo

[POWYSWALES]

On my mk3 fabia there was a button next to the light switch to disable stop/start, does the octavia not have this? Not that i would mind as i found stop/start worked good on the dsg fabia, unless only dsg cars have the stop/start switch? The reason i ask is i am getting an octavia se sport in the next few weeks.

Edited 30 November, 2016 by POWYSWALES

[Item]

On my mk3 fabia there was a button next to the light switch to disable stop/start, does the octavia not have this? Not that i would mind as i found stop/start worked good on the dsg fabia, unless only dsg cars have the stop/start switch? The reason i ask is i am getting an octavia se sport in the next few weeks.

 

There is a switch, but you have to remember to turn it off everytime you start the car - there is no way of setting it to persist outside of messing around with VCDS.

 

It is just habit for me to turn it off whenever I start the car now - I find it way too aggressive to stop the car (VRS DSG) and it bugs me.

[alexbuck]

I do agree it's pretty aggressive...if I pull up at the end of my road to put it into reverse to get up my drive, it switches off if I'm not super careful ????

A bit daft!

[ednmra]

I hate stop/start and turn it off almost without thinking, every time I fire up the car.

Once or twice early on, when I forgot to turn it off, I found I sometimes almost stalled when doing a prompt pull away from traffic lights.

Anyway, hearing and feeling the engine constantly firing up and conking out when around town (i.e. doing a lot of stopping and starting) also makes me wonder how long some of the starter mechanism components will last.

For the sake of one or two less mpg I'd quite happily throw the mechanism, and its designer,  off the nearest cliff !!!

[SuperbTWM]

Its not completely pointless, it does save you a couple of hundred pounds in road tax each year  even it it has a negligable effect on the environment in the real world.

 

Sorry, I can't believe I missed out the main benefit 

[Gerrycan]

The basic Australian variant of the Mk3 I have was interesting for the specification they chose.

Ordinary air-con (not climate control), 1.4tsi (140bhp) was the smallest engine available, no modes (sport, normal, eco) on manual versions, and NO stop/start.

 

The funny thing is that I often choose to turn the engine off with the keyed ignition when I catch the lights at junctions with long cycle times.

Compared to larger capacity engines the 1.4tsi is particularly frugal when just ticking over, as little as 0.5L/hour so I am not sure that there is enormous benefit stopping the engine for less than say 30 seconds.

 

I used to do this with my old mk2 1.9pd and the thing I liked about that engine and the current 1.4tsi is how the engines start immediately on the first compression rather than the feeling I have had on other cars (diesel and petrol) that it takes a couple (or more) cranks to catch and start.

 

For instance I remember on older cars that if the headlights were on then they went out while the engine cranked over to start, while on both Octavia the headlights barely flicker. It suggests to me that the newer engines are much easier to turn over.

 

I quite like the concept of the stop/start used on Mazda SkyActive petrol engines where no starter motor is used, the engine is stopped just after TDC and to restart they inject and ignite a charge. Paradoxically I have heard of complaints from a Mazda owners who have blamed the premature failure of expensive batteries on the stop/start operation? Might be more related to the Mazda 'I-loop' capacitive recharging system?

[Octy0GG]

Its not completely pointless, it does save you a couple of hundred pounds in road tax each year  even it it has a negligable effect on the environment in the real world.

Will have less of an advantage for new cars in UK after tax change next year though