Everything You Ever Wanted to Know About the Start/Stop Feature on your F30 3 series

One of the most interesting, possibly obtrusive and certainly confusing new "EfficientDynamics" features added to the 2012 F30 3 series is the automatic stop start system. Stop/start is standard equipment on all new F30 3 series and is designed to save fuel while the car would otherwise be idling. The stop start functions differently depending on the transmission choice.

Automatic Transmission
Stop/Start will shut off the engine whenever the car is brought to a stop, so long as the transmission remains in D and the brake pedal is pressed to keep the car from moving. The engine is shut off after approximately one second and the tachometer needle will point to the "ready" position. As soon as the brake is released the engine starts and you continue on as normal. The driver can also select P while the engine is off and release the brake pedal, by then selecting D again the car will automatically start.

Manual Transmission
Stop/Start will shut of the engine whenever the car is brought to a stop, the car is in neutral and the clutch pedal is released. The engine is shut off after approximately one second and the tachometer needle will point to the "ready" position. The car is automatically restarted when the clutch pedal is depressed and you continue on as normal.



Interesting Quirks/Features

• The engine can be restarted by the driver in anticipation of driving off by: briefly applying additional pressure to the brake pedal or by releasing the break pedal slightly. Both will cause the engine to start.
• If "Automatic Hold" is activated the car will hold itself once the car has come to a stop and the engine has been switched off freeing the driver from needing to hold the brake pedal. Applying the brakes will cause the engine to start automatically.
• It is possible to prevent engine shut down once stopped in order to be able to drive off quickly. Within one second of stopping apply additional force to the brake pedal and then release the additional pressure and continue holding the brake pedal with "normal" force. Whatever that means.

Why isn't my Stop/Start working?
There are numerous vehicle parameters that are monitored as a part of the stop/start function to ensure the driving experience is not impacted. As many of the factors are not possible to monitor it may appear that the feature is not working. Reasons why the stop/start may not shut down the engine include:

• The car is coasting (manual transmission)
• Brake vacuum reading is too low (manual transmission)
• Insufficient brake pedal pressure is being applied to hold the vehicle stationary (automatic transmission)
• Stopping on a hill/downhill with a 12% or greater gradient
• If the steering angle is more then 6 degrees
• If the steering wheel is still be moved after approximately one second of coming to a stop
• The system has not yet be activated by going over a speed of 5mph for automatics, 3mph for manuals since the last engine switch off
• If the gas pedal is being pressed (engine must be at idle speed only)
• You're coming to a stop from reverse
• The driver gets out of the car
• If Hill Decent Control (HDC) is activated
• If the engine is not up to temperature
• If the carbon canister is being purged
• if the grade of the fuel is too low for the engine
• Transmission adaptation is active (automatic transmission)
• The hydraulic pressure accumulator is not yet up to pressure (automatic transmission)
• Stop-and-go traffic - system is only activated by driving over 5mph for automatics, 3mph for manuals
• Batter charge is low
• Outside temperature is colder then 37.4 F / 3 C
• Outside temperature above 95 F / 35 C and the air conditioning system is on
• Fogging of the windshield is detected by the IHKA system
• Climate control system is on but passenger compartment has not yet reached desired temperature
• ABS system was used when coming to a stop

Alternatively the car may automatically restart outside the standard restart procedure if:

• The driver is moving the steering wheel
• The driver presses the gas pedal
• The transmission was shifted from D to P and subsequently back to D
• The transmission is shifted to N or R
• The battery charge runs low
• Outside temperature rises above 95 F / 35 C and the air conditioning is on
• Fogging of the windshield is detected by the IKHA system
• Low evaporator temperature is detected

Disabling Automatic Stop/Start
The stop/start feature can be manually disable by pressing the button above the engine start button. BMW is now offering the ability for stop start to remember the last mode, meaning if stop/start is shut off and you completely shut down your car, it will remember the last mode and will not automatically re-enable stop/stop start. This can be coded by your dealer, read the service bulletin here -

http://www.bimmerfest.com/forums/sho...d.php?t=636783

Impressions
The Bimmerfest Long Term Review Project 328i is mated with a 6 speed manual. The stop start function impressively does work with the manual transmission, however, I find it odd to sit at a light in neutral with the clutch out. When I was taught to drive manual I was told to always leave the car in gear in case you need to move suddenly. Therefore I tent to sit at lights with the clutch in, in first gear, so the stop start function never acts. When I do remember to use it I think it is the funniest thing to have it shut off the engine. I'll use the feature to entertain passenger and show off the technology of the F30. The rare cases where I'm at long lights it is nice but my daily commute doesn't have enough lights to make the gas savings worth much. It is disappointing that it doesn't work in stop-and-go traffic, that is where I would expect the majority of fuel savings would be seen by F30 3 series owners.

On an automatic where it can function without any change to ones driving habits I think it is a great way to save on gas. If someone with an automatic can comment on how it is that would be great.

I have a manual and find that it is totally annoying in stop and go traffic. I haven't found the situation where it doesn't turn off. It just feels like turning off the engine and then turning it back on a second can't be any good for it.

Great post Tim, especially for me as I have 328i Auto, and for a few days I was sure there was something wrong with the system as it wasn't activating. I believe that was caused by some cold temperatures in the first few days I had the car, as it is now working most of the time.

I find it really interesting in action, and I appreciate the silence and no vibration when the engine is stopped. The vibration as it restarts is a little bit off-putting, but more to passengers than driver I find. In hybrids this system works better because they move off from rest on battery then restart the engine while in motion which is a lot smoother.

Overall I definitely like this feature; just adds to all the other new technology in this car which makes it interesting!

What is: "Transmission adaptation is active (automatic transmission)" ?

I was taught not to sit at a light with the clutch in, due to additional wear on the throwout bearing. Not sure if that's still a concern in modern cars, but seems I wouldn't have to change any habits.

I love this feature at the long and infrequent stop lights, rail road stops (when train is coming)

In a city driving with frequent stops and goes it gets annoying really fast. I think mellow/easy going drivers should not have problem with it.

Agressive drivers will hate it.

Originally Posted by pcbrew

I was taught not to sit at a light with the clutch in, due to additional wear on the throwout bearing. Not sure if that's still a concern in modern cars, but seems I wouldn't have to change any habits.

Absolutely this is still a concern! Clutches haven't changed much.

I still have not driven an F30 but I think S/S would drive me nuts!!!

Thanks Tim. It sounds similar to my wife's Honda Insight hybrid. The stop/start feature is something you get used to after a while. Then it becomes second nature.

During my test drive I found it to produce a lot of vibration at start up - definitely noticeable. I would turn it off all the time. Not worth the 1 mpg it probably saves. It's a $40-$50k car and that start up vibration cheapens the experience.

also pulling a paddle starts the engine

My personal preference is to shut off the Auto Start/Stop. I admit, I may just not be willing to adapt to a new technology that in the long run could save me money at the gas tank....I just can't seem to get comfortable with what I call the "Bimmer shimmy-shake" that my F30 does each time the battery turns off and on....I have to confess, the first time I experienced the Auto Start/Stop at the first stop light we encountered, my wife and I looked at each other in horror thinking that our car stalled. Then when it came back alive, we both breathed a sigh of relief. I admit, during our test drive, we had not experienced the Stop/Start feature, we were just aware of it as a standard feature and I thought to myself, "That's cool."But since we test drove on the highway in Sport mode (yes, sport mode made me fall in love with this Bimmer), we never had stopped at a stop light or anything of the sort! So my usual ritual is to make sure I push the Auto Start/Stop button after selecting the Sport Mode and I'm off into the countryside for a quick drive or set my mode back to Comfort Mode when I'm back in town (and proceed to make sure Auto Start/Stop is off). And then of course, I'm looking forward to a long road trip to try out the Eco Mode....

Maybe in the future, I'll give Auto Start/Stop a chance again....Time will tell if I'm able to evolve or not. We should count ourselves lucky, since we have an option to turn this feature on and off. By the way, do the other hybrids (i.e. Prius, etc) do the 'shimmy-shake' that the Bimmer does?

You may find that you have to change your driving style if you allow auto start / stop to operate. The worst part is when you are turning left across traffic, as you have to allow 2-3 seconds for the car to start back up before you can turn. I usually just turn auto start/stop off.

Originally Posted by tim330i

...however, I find it odd to sit at a light in neutral with the clutch out. When I was taught to drive manual I was told to always leave the car in gear in case you need to move suddenly. Therefore I tent to sit at lights with the clutch in, in first gear, so the stop start function never acts...

Really? [!]

Back in the early 80s, my pop used to yell @ me for doing that in our F150. And the clutch on the F150 did eventually fail from broken fingers on the pressure plate. The guys in the shop backed my father saying it was because I'd leave the clutch depressed for long periods of time. ... these days, I yell at my wife if I catch her doing it even for seconds.

So looks like autostop should be quite natural for me, cause neutral no clutch is the only way I [don't] roll.

OK, so this feature save 1 mpg in city driving. The saving may never be offset by the increased maintenance costs of premature starter wear. Only time will tell how the starters are holding up in this severe use. Also keep in mind that when you restart the car it uses electrical energy from the battery which needs to be recharged when the engine is restarted. On short stops there may be no savings at all.

Originally Posted by silberma

OK, so this feature save 1 mpg in city driving. The saving may never be offset by the increased maintenance costs of premature starter wear. Only time will tell how the starters are holding up in this severe use. Also keep in mind that when you restart the car it uses electrical energy from the battery which needs to be recharged when the engine is restarted. On short stops there may be no savings at all.

I was thinking the same thing on my test drive. It stopped probably four or five times for 10-20 seconds each time. After factoring in a recharge of the battery after each start, I really wonder how much fuel savings there is. I can see some savings in city traffic where you are at red lights often and a minute at a time.

It would be interesting to see some controlled tests of this with it on and off.

silberma, I read somewhere that the auto stop/start uses its own starter.

Originally Posted by stampchez

I have a manual and find that it is totally annoying in stop and go traffic. I haven't found the situation where it doesn't turn off. It just feels like turning off the engine and then turning it back on a second can't be any good for it.

Yikes. I agree. Can this "feature" be disabled once and for all?

Originally Posted by bcl0328

silberma, I read somewhere that the auto stop/start uses its own starter.

There is only one starter in the car. RealOEM

Originally Posted by ljgmdad

Yikes. I agree. Can this "feature" be disabled once and for all?

You can't change the default to be off. I leave it on unless I'm creeping in stop and go traffic. I really don't mind it at all at red lights. With a manual, it won't turn off for quick stops if you leave the clutch in.

After about a week in my 335 Auto I too find it annoying. Will give it more time to make sure I really hate it. If so, its on the list to be coded - it possible.

Originally Posted by stampchez

You can't change the default to be off. I leave it on unless I'm creeping in stop and go traffic. I really don't mind it at all at red lights. With a manual, it won't turn off for quick stops if you leave the clutch in.

If you want to start quickly from a stop, does it come on in time?

Originally Posted by ljgmdad

If you want to start quickly from a stop, does it come on in time?

It's ready to go by the time you get your foot on the clutch and move the shifter into first.

Whether you like it or not is a personal thing, I guess. What I hate is that you can't permanently turn it off. Give us the damn choice! Is that too much to ask?!

I would expect that there could be a fairly easy hardware workaround to disable the auto start stop automatically when the car is started, assuming you're just closing a set of contacts on the disable switch. Might have warranty implications, though.

Originally Posted by stampchez

It's ready to go by the time you get your foot on the clutch and move the shifter into first.

Makes sense. So I guess if you never take your foot off the clutch the engine never stops. What about the AT though?

Someone needs to write a program for:

1. Defaulting to and staying in sports mode
2. Default disabling of auto start/stop

Originally Posted by CE750Jockey

Whether you like it or not is a personal thing, I guess. What I hate is that you can't permanently turn it off. Give us the damn choice! Is that too much to ask?!

Yes it's too much to ask of BMW. The car's CAFE numbers are based on stop/start being part of the normal operation of the car. If BMW allowed it to be defeated it would have to be tested for CAFE in that mode. Don't ever forget that is all about meeting CAFE requirements and will be normal on last cars in the next few years. Get used to it.