BMW Engine Start Stop Feature

[Disco Dave]

Does having the air conditioner switched on deactivate the stop/start function?

 

[Shopkeep]

Ok, let me post a different opinion: first time in my life I drive a start-stop car. It is really OK, especially in town at traffic lights. Why pollute or spend gasoline when stopped anyway?

In a fraction of a second, the motor is running again. And I have driven more than 2000 km now, without pushing that "off" button.

So, I will keep using it.

I agree, not sure why so many have an issue with it. By the time you have taken your foot off the brake and moved to the accelerator the engine is up and running and good to go. These engines were designed with start/stop in mind, it is not a new concept or technology and it saves you money.

If you constantly drive a car like you stole it then by all means turn it off, but not sure the Grenadier is that type of motor.

 

[DenisM]

An issue for stop/start driving for short distances (less than 5km) in congested city environs can be that the starter battery does not receive sufficient charge to recover energy lost in multiple stop/start cycles through the journey. Where we live for example, there are 14 sets of traffic lights to negotiate the 2.5km to the "express way". (Once on the express way we can drive almost 400km south with no further traffic lights!).
Just three weeks after taking delivery of my wife's 2020 Subaru Impreza she was "upset" the remote wouldn't open the door... so having showed her the physical key and opened the single door with a lock... the vehicle was "dead". Multimeter showed 11.2V on the starter battery. A long slow charge set to "recondition" and some seven hrs later it roared into life... Meanwhile I made up a lead with an Anderson plug and a cover and installed it permanently on the battery. Each second Saturday morning, the charger is plugged into the Anderson plug and a couple of hrs later is in 'float' mode. I have also (almost) trained her to press the "A" button as soon as the engine starts to disable the stop/start function....

 

[DaveB]

I agree, not sure why so many have an issue with it. By the time you have taken your foot off the brake and moved to the accelerator the engine is up and running and good to go. These engines were designed with start/stop in mind, it is not a new concept or technology and it saves you money.

If you constantly drive a car like you stole it then by all means turn it off, but not sure the Grenadier is that type of motor.

There is nothing worse than sitting at the light, waiting for it to go green so you can race the guy next to you, only to find the stop start kicked in.
1-2 seconds wasted

 

[Tazzieman]

There is nothing worse than sitting at the light, waiting for it to go green so you can race the guy next to you, only to find the stop start kicked in.
1-2 seconds wasted

Yes , that's why she got the 408hp EV Have not lost at the lights thusfar.

 

[AnD3rew]

I have no experience with engine stop start features. Is this a good feature or a pain in the arse?

I’d say neither. It does save a little fuel and reduces emissions a bit. If you are driving lesiurely around the city it’s not that annoying. If you are trying to drive in a spirited manner it can be annoying and in some specific situations it’s annoying. Some cars do it better than others, with some it’s barely noticeable, with some its clunky and noisy. But it’s easy to just push the button and turn it off.

 

[trobex]

Does a diesel starting and stopping all the time increase the of DPF regen required?

 

[Jean Mercier]

Does having the air conditioner switched on deactivate the stop/start function?

Yes, in some situations it is deactivated automatically, for instance when air conditioning is on. I would expect that it also happens when the battery is below some level.

 

[Arkaig]

I agree, not sure why so many have an issue with it. By the time you have taken your foot off the brake and moved to the accelerator the engine is up and running and good to go. These engines were designed with start/stop in mind, it is not a new concept or technology and it saves you money.

I agree too, I really don't understand what all the fuss is about, the stop-start on the Gren works perfectly well - for those keen to re-engage the ignition simply requires either a twitch of the steering wheel or a marginal lifting of the pressure on the brake pedal.

 

[DCPU]

I agree, not sure why so many have an issue with it. By the time you have taken your foot off the brake and moved to the accelerator the engine is up and running and good to go. These engines were designed with start/stop in mind, it is not a new concept or technology and it saves you money.

I have an issue with all things like this, because they were not designed for the health of the engine or my wallet but external factors.

Whilst I can accept this in the wider context of the world we live in, I also will think of the former. It is just not mechanically sympathetic to keep switching an engine off/on multiple times on a single journey.

I'd also question if it saves me money? First off all the start/stop equipment is far more costly than an engine with normal starter motors, alternators, etc; then there's the wear and tear and service costs associated with this equipment. Over any length of time, 1, 3, 5 or 10 years, I doubt that fuel savings will bring me out ahead.

They are what they are, a necessary evil.

 

[AnD3rew]

Yes, in some situations it is deactivated automatically, for instance when air conditioning is on. I would expect that it also happens when the battery is below some level.

The aircon doesn’t de activate in most cars, don’t know about the Grenadier, but when the temperature starts to rise it will auto restart, so if you have the aircon temp set very cool and it is a hot day, the car either won’t stop or it will stop for short periods and the restart quite quickly.

 

[DCPU]

The one that puzzles me is the bonnet not properly closed? Why?

 

[Shopkeep]

I have an issue with all things like this, because they were not designed for the health of the engine or my wallet but external factors.

Whilst I can accept this in the wider context of the world we live in, I also will think of the former. It is just not mechanically sympathetic to keep switching an engine off/on multiple times on a single journey.

I'd also question if it saves me money? First off all the start/stop equipment is far more costly than an engine with normal starter motors, alternators, etc; then there's the wear and tear and service costs associated with this equipment. Over any length of time, 1, 3, 5 or 10 years, I doubt that fuel savings will bring me out ahead.

They are what they are, a necessary evil.

BMW have been using it since 2008, if it was causing any additional stress or strains on the engines or components this would have manifested by now.

Its a bit like the argument that you should leave the lights constantly on in a room instead of turning them on and off each time you come and go, don't want to wear out those light bulbs.....

 

[DCPU]

BMW have been using it since 2008, if it was causing any additional stress or strains on the engines or components this would have manifested by now.

So, you're absolutely certain it hasn't?

Its a bit like the argument that you should leave the lights constantly on in a room instead of turning them on and off each time you come and go, don't want to wear out those light bulbs.....

If the argument is backed up by hard facts and figures then why wouldn't you?

 

[globalgregors]

View attachment 7812853
The one that puzzles me is the bonnet not properly closed? Why?

Would this be a safety feature, so that an engine idling with the bonnet open doesn’t do an Eco Stop, inviting hands in before Eco Starting a couple of digits off?

 

[DCPU]

Well that now makes sense to me.

 

[trobex]

BMW have been using it since 2008, if it was causing any additional stress or strains on the engines or components this would have manifested by now.

Its a bit like the argument that you should leave the lights constantly on in a room instead of turning them on and off each time you come and go, don't want to wear out those light bulbs.....

BMW had numerous with issues to their Diesel engines leading up to around 2016... "BMTroubleU" and they do still have some issues now if you go to the BMW forums. Cannot say if the stop start/carbon reduction technology changes are the cause but maybe. But plenty of BMW owners have no real issues except massive depreciation and expensive servicing. The B57 though seems to be ok (one of the better Diesels) but even they have issues with DPFs and a few other 'modern tech' components. Is the stop start affecting these - who knows BMW don't give out that level of detail for repairs/fixes if you trawl through enough BMW forum posts (that is the gist of it).

I know for sure, that I will be permanently disabling stop start as soon as it is made possible. It was on the wife CX5 petrol (but isn't anymore).. nearly killed me at a few roundabouts even the .5 seconds is enough to stress one out.

 

[Fab]

View attachment 7812853
The one that puzzles me is the bonnet not properly closed? Why?

Maybe for checking a running engine?

 

[emax]

I don't know (yet) how the start-stop function works in the Grenadier.

But I would like to have it so that it only intervenes when the engine is at operating temperature. I'd consider anything else a massive design flaw.

 

[Shopkeep]

I don't know (yet) how the start-stop function works in the Grenadier.

But I would like to have it so that only intervenes when the engine is at operating temperature. I'd consider anything else a massive design flaw.

Only works when engine has reached safe operating temp.

This article is a good summary:

Stop-start systems: is there a long-term impact on my car’s engine? | Autocar

It's designed to save fuel and reduce emissions, but what effect does the technology have on engine life?

www.autocar.co.uk