[sorin1987]

I've had my 2020 G31 for about 4 months now. Previously I had the 3.0L E90, which didn't have the SS function. I find this function useless and even annoying especially since I do a lot of city traffic driving and sometime the engine would stop just to start after one second because I just stoped at a Give Way sign or I stopped behind a car and that car decides to move for 2m forward (I think the car has a sensor that detects if the car in front moves and it starts the engine again thinking you will move but you are still in a line and I wouldn't move). So I disable it, when I start the engine I press both the Start and the Disable SS buttons at the same time.

My questions are:
Can this function actually harm the engine and components if I it starts and stops so many times, even within seconds? I know my driving instructor (from 18 years ago) kept saying that starting and stopping the engine is harmful and if you can you should avoid short car journeys. Also would it damage the battery life by keeping the engine off but the AC and infotainment on?

Would it save any petrol? I assume that is the primary reason for this to exist. But I am not sure if when it starts the engine it will pull more petrol (like the old cars used to do) and therefore negate the saving it did while stopped.

Thanks

[AP]

I guess it worth looking at the f10 forums, ASS was introduced to the 5 series shortly after it was introduced. ( had it on my 2012 model)
I have personally not read if any issues people have had there as regards starter motors. These guys would have the age and mileage under their belts now so would be best placed to highlight that. As I say I’ve not seen anything on that personally not to say that there isn’t .

Not sure about the engine itself. I’m sure mechanics here can help out

I’m sure it save fuel if it’s used where you stop for x seconds or more. The value of x I don’t know
This video may be worth a watch
https://youtu.be/dFImHhNwbJo?si=3oJHRwLKikq5jVZh


Personally I disable it as I dislike the lack of refinement about it on my m550. The hybrids I suspect would be smoother

[Joe-BMW33]

In terms of wear and tear, when ASS was first introduced, all of the car guys went nuts about it causing the starter to wear out quickly. Fast forward 13 years or so, I think that theory has been debunked.

It was annoying 13 years ago and is still as equally annoying today for me and others. So it's about being annoying for me. I have an M550, I could give two shits about mileage gains from it. Having the engine kill on every stop and starting and stopping constantly in bumper traffic just isn't normal. I haven't coded it out on my X5 (and I am not sure I can) because my GF thinks the car is "so quiet". It's a "feature" made for broads who don't notice it.

[Neusser]

Originally Posted by sorin1987

I've had my 2020 G31 for about 4 months now. Previously I had the 3.0L E90, which didn't have the SS function. I find this function useless and even annoying especially since I do a lot of city traffic driving and sometime the engine would stop just to start after one second because I just stoped at a Give Way sign or I stopped behind a car and that car decides to move for 2m forward (I think the car has a sensor that detects if the car in front moves and it starts the engine again thinking you will move but you are still in a line and I wouldn't move). So I disable it, when I start the engine I press both the Start and the Disable SS buttons at the same time.

My questions are:
Can this function actually harm the engine and components if I it starts and stops so many times, even within seconds? I know my driving instructor (from 18 years ago) kept saying that starting and stopping the engine is harmful and if you can you should avoid short car journeys. Also would it damage the battery life by keeping the engine off but the AC and infotainment on?

Would it save any petrol? I assume that is the primary reason for this to exist. But I am not sure if when it starts the engine it will pull more petrol (like the old cars used to do) and therefore negate the saving it did while stopped.

Thanks

I turn it off in stop-and-go traffic, but use it otherwise (in normal driving).

Definitely saves gas, which most people would consider rather useful.

We can't all be powerfully built directors and CEOs.

[Joe-BMW33]

Originally Posted by Neusser

I turn it off in stop-and-go traffic, but use it otherwise (in normal driving).

Definitely saves gas, which most people would consider rather useful.

We can't all be powerfully built directors and CEOs.

Look at you, knowing and staying in your lane. Kudos.

[eric_gm]

I happily paid for Bimmercode and a Bluetooth OBD adapter to disable ASS (apt name).

Never had a car with the feature so I went in with an open mind but hated it almost immediately. Even in my driveway when parking the engine would stop. Also, living in a hot & humid hellhole having AC blow warm-ish air is annoying.

The fuel gains can be up to 8% in heavy traffic. Of course if you don't drive a lot or it's mostly highway driving, it can be much, much less.

Regardless of how older cars with ASS have fared, nobody can convince me a starter and battery are not under a lot more stress.

Here's the study: https://www.sae.org/publications/tec.../2023-01-0346/

[G30M]

they had to add bearing coating reinforcement to *prevent premature wear - * for me it means reduce

that means yes it puts more wear

that means if you turn it off your bearing sleeve should last longer

[G30M]

from a N55 technical training manual a few years ago ...

[HerkHealer]

I'd bet BMW Engineers figured out the starters will fail shortly after warranty expires.
I despise ASS. Thank god I was able to code mine off.

[MauiSteve]

The very first thing I did after buying Bimmercode was to disable ASS. It not so much a disable function but a remember last setting function so that when the vehicle starts up in comfort mode if you had ASS off when you turned off the car then ASS will still be off at starting the car- so you don't have to push the button. If I put the car in ECO mode ASS seems to enable itself just while in ECO.

[Neusser]

Originally Posted by Joe-BMW33

Look at you, knowing and staying in your lane. Kudos.

Hook, line, and sinker.

[ppointer]

I hate ASS and coded it out, like others in this thread have mentioned. Note that if you are in Sport mode, start-stop should be disabled.

[Gautam]

There’s a long thread in the f30 section surveying owners on issues versus usage of ASS. It’s anecdata, but there are loose correlations. Best not to chance it imho, even aside from the annoyance factor. Two things are factual, it puts more wear on the car while it also reduces emissions. Highly debatable what the actual impact is in each of those areas.

[sorin1987]

Originally Posted by ppointer

I hate ASS and coded it out, like others in this thread have mentioned. Note that if you are in Sport mode, start-stop should be disabled.

Noob question but why are people coding it out? Just so that you don't have to press the button to disable it when you start the car anymore? I just press both the START and Disable ASS at the same time. Are there other benefits of completely disabling it?

[Joe-BMW33]

Originally Posted by Neusser

Hook, line, and sinker.

Yup, you took it. Keep counting those pennies.

[Joe-BMW33]

Originally Posted by sorin1987

Noob question but why are people coding it out? Just so that you don't have to press the button to disable it when you start the car anymore? I just press both the START and Disable ASS at the same time. Are there other benefits of completely disabling it?

Yes, so we don't have to go through those motions and a lot of the newer cars don't have the on/off button, so you are stuck with it if you don't code it.

Most of us code "remember last setting" if you have the button. If it's off when you shut down the car, it will be off when you start up. If it's on, it will be on when you start the car.

For cars that can't be coded to either disable it or remember last setting, most people code the car to start in sport individual.

Yes, if you are programmed to disable it on every start, all the power to you. I have just coded it out for 15 years or so, so that's the route I take. I coded it out in the dealer parking lot on delivery.

[sguida]

I turn it on when driving to work. Sitting at lights, my engine is off at least 1 hour in between fill-ups.

This has to be putting $$$ in my pocket.

[AP]

If you like it leave it on , it’s your personal choice of course

[adhrp]

Funny thing is back when I had my F30 and wasn't knowledgeable about coding and stuff, I just asked my dealer to code it to stay at last setting and they did it during a routine oil change service. I suppose nowadays dealers would not do that.

[tjbuggy2b]

It would be nice if you could code it to stop only if at rest for more than 5 seconds, or something.

[AP]

I think I read in the us you could do that before regulations kicked in preventing them doing that

You wait until next year in the EU , the top items I predict will be on coders list will be disabling lane departure warning off and mandatory speed limiters
Assuming this come in of course

The mandatory speed limiters have been in the cards for a few years now. The technology has been in the cars for quite a while

[Joe-BMW33]

Originally Posted by adhrp

Funny thing is back when I had my F30 and wasn't knowledgeable about coding and stuff, I just asked my dealer to code it to stay at last setting and they did it during a routine oil change service. I suppose nowadays dealers would not do that.

They used to do this when it was new on the F chassis cars. Most of the time they would charge you $150. They won't do it anymore.