[Maestro]

Had our X3 for 3 months now, first car we owned with the auto stop/start feature to save gas. I had rental cars with this feature and always disable it since it seem more annoying than it help.

First, I do understand the purpose of the feature that is not my question. I am trying to understand how BMW may have intended it to work and the use cases for the feature.

I know when you come to complete stop and the feature is enable the engine turns off and when you lift your foot from the brake it start the engine. It couldn't be any simpler but did BMW have bigger ideas for will all the sensors on the car.

Here are my observations which in all cases I can not explain why it reacts the way it does.

Sometime when coming to a stop behind another vehicle the engine does not stop and I see the stop/start indicator will all of a sudden is crossed out as if it has been disable. The manual says if you momentarily take pressure off the brake the engines turns on, and you can reengage it by lifting off the brake and press down harder. This does not always work and I can not explain why sometime it will not shut off when the brake is reapplied.

Other times it does shut off and stays off monetary then without me doing anything including not lifting the brake it just turns on and the stop/start is disable. Other times it does not show disable and I can partially release the brake and press again and it stuff off again and stay off until I release the brake.

I also noticed if the engine eventually turns off and stays off and the car in front of me pulls away the engine will start. I kind of like this feature, but again I am not sure it is doing this on purpose or it is related to the above situation. I also swear that it turns on when I am first car at a red light and engine will restart as soon as the light turns from red to green. Again I am not 100% sure this is actually happen or it just another weird issue. I tried observing if the red light position makes a difference.

Lastly, when you stop in a parking space, it has intermittently just turn off the engine. If I place the car in park before it turns on, the engine will stay in standby. Then if you open the door everything turns off as you would expect. I have enable the feature where it turns off the engine when the doors are open, but this only works if when you park and the engine also stops. If the engine is running after you place the car in park with or w/o the stop/state indictor showing disable and you open the door the engine continues to run. If you walk away it continues to run and never shuts off. I did this once thinking it should just shut off since I enable the auto shutoff when doors are open. That was mistake coming back to the car finding it still running.

Has anyone else observed these behavior, if so do you know why it is doing these things. Or should I take it in for service and say the car has come new car gremlins.

So those are all the weird states I have encounter with Stop/Start feature

[et_aruba]

I am by no means an expert, but let me give this a go...

The newer vehicles have a super-smart auto start/stop function (in my opinion) and much better than previous year vehicles equipped with this feature. Previous generations just sense when the car is stopped and turns the vehicle off. Newer vehicles, not sure which year this was introduced, incorporate other systems into this functionality. For example, the KAFAS cameras, misc. cameras if applicable and other sensors will know when there is a car in front of you and/or if the car in front of you is driving away. I believe the distance and elemental variables are taken into account in terms of how well the system works. If I am stopped behind a car and my BMW turns off (auto-stop) and the car in front of me pulls away, my BMW automatically starts before I can take my foot off the brake. If I am at an intersection with my blinkers on, my BMW will not shut off, because it knows I am about to make a turn.

I'll see if I can put the short version on here next...

[et_aruba]

Technical Training Product Information G01 Powertrain, page 24 of 38:

5.3.MSA Connected 1.0

The official name for MSA Connected 1.0 is “Intelligent automatic start-stop function”.

The MSA Connected 1.0 enables information from the navigation system and/or the camera-and radar-based assistance systems to be used to predict how long a stop might last. The automatic engine start-stop function responds differently depending on the length of the stop:
•Short vehicle stop
Example: Crossing where the driver needs to “give way to the right” The effort required to start the engine is larger than the fuel economy improvement from stopping the engine → Prevent the engine from the stopping → Engine idling.

Coming from a 2017 X3 with this function, I can tell you first-hand, the newer system is much more efficient and effective.

[et_aruba]

See link below, you want to pull up document 02, G01 Powertrain.pdf

https://x3.xbimmers.com/forums/showthread.php?t=1563521

Hope this helps...

[freshxdough]

Everything you have explained is correct operation of MSA for G01 vehicle. There are several factors that decide whether or not the engine will turn off at a stop. If it shows the icon displaying a cross through the start/stop icon, don't be alarmed. It could be due to interior vehicle temperature, engine temperature, cooling demands, battery charge level etc.

When the engine is off it will continue monitoring these things. For example if the battery voltage drops below the threshold level, the engine will start by itself. Or if you're running the AC and the interior temp starts to rise again the engine will turn on to continue with keeping the cabin temperature adequate.

When the engine does turn off and the car in front of you pulls away, your engine will turn on as it anticipates you obviously continuing forward. This is used by the radar sensor in the lower grille(I believe only if you have active cruise control option).

[freshxdough]

Oh, and not to mention the MSA takes into account the location you're at. So for example it can prevent the engine turning off if you're waiting at a light to turn left on a yield for example. It's not always perfect, but it is intelligent. It seems like most of the time I knows when it should or should not shut off.

If you're the type of person who comes to a stop and continues creeping up and up, you're never going to like the MSA system as you would think it's always interfering.

[Maestro]

Okay, thanks for confirm it is doing most of this on purpose and BMW trying to make it smart, but it felt more random than logical. I could not seem to find a reason for why it did or did not stop in a specific instance. I knew about the turn signal feature, I did read that. I know it did not turn off due to air-condition since it has been cool out, no AC has been on so i do not believe it was trying to maintain comfort controls

I think the system is still in a learning mode though. I was driving last night and pull up behind stop traffic on a road with many lights and half the time it turn off the engine and stayed off until the car in front move or I let off the brake (but it did not always turn back on when the car in front moved), the other half it either did the stop start immediately and disable the feature or it never stop even though traffic conditions were the same and the time at lights were long like more than a minute.

I wonder how the MSA determines the "Efficient time" I notice is also use the navigation system so I wonder if it know average wait times are certain intersections. As an engineer, this kind of things drives me craze when it can not figure the logic of an system and what it is doing and why.

The last one to figure out is why sometime it does no go into standby when parking and why when the doors are open the engine does not stop since the I have that feature enable.

[rob175]

For all of the reasons mentioned in previous threads and more are the reasons I ALWAYS turn it off when I start the car and I'm about to code it off permanently using Bimmercode software.

I'm NOT convinced repeated engine starts will be "good" for the starter and battery. I typically keep a car for 7 to 10 years. The last time I replaced a stater and solenoid was in 1977 on a 1973 Chevy Camero (lol...my last domestic car!). It just makes common sense that a starter used thousands of times MORE than to simply start the car a few times a day, will not last as long.....and the cost to replace one starter is much more money than the few drops of fuel saved. (Does anyone really know how many gallons of gas are saved per year using the stop/start?)

The system was "forced" upon the manufacturers by the EPA. They didn't implement it by choice.

[LogicalApex]

Originally Posted by rob175

For all of the reasons mentioned in previous threads and more are the reasons I ALWAYS turn it off when I start the car and I'm about to code it off permanently using Bimmercode software.

I'm NOT convinced repeated engine starts will be "good" for the starter and battery. I typically keep a car for 7 to 10 years. The last time I replaced a stater and solenoid was in 1977 on a 1973 Chevy Camero (lol...my last domestic car!). It just makes common sense that a starter used thousands of times MORE than to simply start the car a few times a day, will not last as long.....and the cost to replace one starter is much more money than the few drops of fuel saved. (Does anyone really know how many gallons of gas are saved per year using the stop/start?)

The system was "forced" upon the manufacturers by the EPA. They didn't implement it by choice.

I hear you, but do you have any data on a spike in starter replacements? The starters were designed for this and the system isn't being started in the same manner as a classic vehicle start to minimize the demand on the system to turn the engine over.

My last car I left Auto Start-Stop on and never turned it off. The starter was fine when I sold the car after 5Y and it had 90K miles on it when I sold it (I added over 80K miles on it). Lots of city driving where I'd have a start stop engagement every 300 feet.

I always hear people cite increased failure risk as a thing with auto start stop, but no one ever has any data of cars with this technology having abnormal starter failures. Consumer reports also doesn't show it. This technology isn't new and has been on cars for over a decade now.

I'd imagine it is even more reliable on the cars with MHT such that the starter is essentially replaced with a 48V starter that's essentially a generator.

[MALOW_]

Originally Posted by LogicalApex

I hear you, but do you have any data on a spike in starter replacements? The starters were designed for this and the system isn't being started in the same manner as a classic vehicle start to minimize the demand on the system to turn the engine over.

My last car I left Auto Start-Stop on and never turned it off. The starter was fine when I sold the car after 5Y and it had 90K miles on it when I sold it (I added over 80K miles on it). Lots of city driving where I'd have a start stop engagement every 300 feet.

I always hear people cite increased failure risk as a thing with auto start stop, but no one ever has any data of cars with this technology having abnormal starter failures. Consumer reports also doesn't show it. This technology isn't new and has been on cars for over a decade now.

I'd imagine it is even more reliable on the cars with MHT such that the starter is essentially replaced with a 48V starter that's essentially a generator.

In my x4 with MHT is not posible to disable ASS. Only by coding. As you said, I don't think necessary to do it.
If I don't want ASS I simply put sport mode.

[rob175]

Perhaps you are correct......so I'll suffice it to say personally....the ONLY time I want my engine to shut off is when I turn the key or press the button to turn it off. I guess I'm just "old fashioned". My system seems pretty fool proof and doesn't require a computer, sensors, technologically advanced starters or engine designs.....do I use perhaps 2% to 3% more fuel in stop and go traffic, perhaps, does the car move forward the split second I press the gas peddle, always.

Not that I'm made of money but the slight savings in fuel means nada to me....besides as more and more electrics hit the road refineries might sell cheaper gas....less demand could mean lower fuel prices....who knows?

[wdeerfield]

Took all of 1 min to enable memory in bimmercode and now I don't have to deal with it anymore. Definitely find it more of an annoyance than helpful

[freshxdough]

Originally Posted by Maestro

Okay, thanks for confirm it is doing most of this on purpose and BMW trying to make it smart, but it felt more random than logical. I could not seem to find a reason for why it did or did not stop in a specific instance. I knew about the turn signal feature, I did read that. I know it did not turn off due to air-condition since it has been cool out, no AC has been on so i do not believe it was trying to maintain comfort controls

I think the system is still in a learning mode though. I was driving last night and pull up behind stop traffic on a road with many lights and half the time it turn off the engine and stayed off until the car in front move or I let off the brake (but it did not always turn back on when the car in front moved), the other half it either did the stop start immediately and disable the feature or it never stop even though traffic conditions were the same and the time at lights were long like more than a minute.

I wonder how the MSA determines the "Efficient time" I notice is also use the navigation system so I wonder if it know average wait times are certain intersections. As an engineer, this kind of things drives me craze when it can not figure the logic of an system and what it is doing and why.

The last one to figure out is why sometime it does no go into standby when parking and why when the doors are open the engine does not stop since the I have that feature enable.

The engine will not shut off with the feature you are describing. You must turn off the engine. And then open the door and the ignition will turn off.

[gugin]

Originally Posted by rob175

besides as more and more electrics hit the road refineries might sell cheaper gas....less demand could mean lower fuel prices....who knows?

Or as more as more electrics hit the market and become more affordable, the government will tax the heck out of gasoline to incentivize people to switch.

[MunkyUK]

I can’t believe what tech BMW put in now. Coming from an old Citroen C4 Picasso its blowing my mind!

[rob175]

Sure, I can understand the governments' desire to encourage more electric vehicles. But consider the tens of millions who have NO ABILITY to easily plug their vehicles for recharging. Those will never consider electric to be practical.

Many people in urban areas park on the street, don't have garages or the ability to run extension cords from their homes/apartments to a car parked on the street overnight. Charging stations are built to make a profit so those costs will climb (and probably will) eventually becoming as costly as buying gasoline.

Personally, I believe that as more electric cars are built, demand for fossil fuels might actually drop...as demand drops so do prices. We saw that happen during the pandemic......capacity and supply outpaced demand and prices fell.

[zukmeister]

I'm going to code mine off as well. The most annoying thing for me is that when you're slowing down sometimes it will turn off before you're completely stopped.

[JBNH]

I'm not sure about BMW, but I know a lot of manufacturers have changed the whole starter motor setup to handle a lifetime of these events. I believe the method involves different gearing for lower starter motor RPMs, along with stopping the engine with a particular cylinder at top dead center (or just past), allowing the restart to happen quicker vs waiting for a full crank rotation (again reducing the total revolutions of the starter).

Long story short, it's a lot more in depth than just "my starter is wearing out because the engine is starting more."

[fdpxfunix]

Just adding my 2 pence worth...

Having now owned my 2018 G01 (30d) for just over 3 weeks, the start/stop is working just like I expected and I do like the feature of when a car moves off in front the engine starts. I leave mine enabled most of the time, but if I know I’m in a queueing situation to get out at a junction (for example) and the traffic is still moving very slowly… I disable it as I feel much more in control with the engine running and not constantly going off/on/off/on all the time. There’s nothing worse than the car stopping, engine goes off, then you have to move off straightaway especially if you’re at the head of the queue and it’s your turn to get onto a main road. Yes the engine fires up quickly & you can move off relatively quickly too, but I just like being in control. My start/stop also follows the rules of engine up to temperature before it kicks in, but I haven’t noticed it not stopping due to outside temperatures yet. It’s too warm in the UK right now… although we could hardly call it warm at the moment.

Now… someone mentioned starter motors and the load put on them with start/stop a few posts back. So, I owned my 2010 E84 (18d) X1 from July 2011 to April 2021. It had 7100 miles on the clock at purchase and I traded it for the X3 at 163300 miles. In the 156200 miles I drove it, I never had to change the starter motor or battery. All those components that start/stop might affect seemed fine. In fact the only engine bay related items I had to change were a water pump, engine sump gasket, rocker head oil breather pipe, drive belt and some pullies. (Also never changed any part of the exhaust. It was still the factory exhaust)

I know BMW probably don’t ‘make them like they used to’, but I have no worries about the starter motor on the X3 going bang anytime soon.

A slightly ironic/funny thing though...... At the time I traded my X1 in, the start/stop system itself had stopped working, but the starter motor was still going strong.

[jrodri7]

Originally Posted by rob175

For all of the reasons mentioned in previous threads and more are the reasons I ALWAYS turn it off when I start the car and I'm about to code it off permanently using Bimmercode software.

I'm NOT convinced repeated engine starts will be "good" for the starter and battery. I typically keep a car for 7 to 10 years. The last time I replaced a stater and solenoid was in 1977 on a 1973 Chevy Camero (lol...my last domestic car!). It just makes common sense that a starter used thousands of times MORE than to simply start the car a few times a day, will not last as long.....and the cost to replace one starter is much more money than the few drops of fuel saved. (Does anyone really know how many gallons of gas are saved per year using the stop/start?)

The system was "forced" upon the manufacturers by the EPA. They didn't implement it by choice.

These components were beefed up as a result of their use in hybrids over a decade ago, so they have been tested for millions of miles throughout car fleets. For example, I believe the switch to the AGM batteries and the quick starting heavy duty starters were all derived from them.

But regardless, the start-stop system was only ever designed to at most get you a 5% efficiency, I think it was more about the GG emissions over a manufacturer's entire fleet that was the basis for rolling out efficient dynamics to every vehicle.

And anyone who thinks the EPA has more onerous guidelines on vehicle emissions and efficiency is clearly deluded.

[Maestro]

Originally Posted by freshxdough

The engine will not shut off with the feature you are describing. You must turn off the engine. And then open the door and the ignition will turn off.

Actually, the X3 has from time to time shut off when the doors are open, it does not happen all the time can not figure out why.

The other related issue and this too is intermittent, when I pull up, park and the engine Auto Stop and you open the door some time the car turns off complete ie the dash shut down and other time the everything stays on even the radio continues playing and a few time I came out of the house to find the marker lights on because it was dark.

[freshxdough]

Originally Posted by Maestro

Actually, the X3 has from time to time shut off when the doors are open, it does not happen all the time can not figure out why.

The other related issue and this too is intermittent, when I pull up, park and the engine Auto Stop and you open the door some time the car turns off complete ie the dash shut down and other time the everything stays on even the radio continues playing and a few time I came out of the house to find the marker lights on because it was dark.

It may be because the engine has shut off with MSA. It can do it if you put it in park too. This feature is not designed to shut off the engine. It is only designed to turn off the ignition once the journey has ended and the start stop button has already been pressed to turn off the engine.