[RASHID007]

As the title says (sorry couldn't resist wording it that way) I just traded in my F30 335i RWD for a 2014 535d X-Drive. Needed something bigger, quieter and more comfortable.

I LOVE everything about the 535d EXCEPT the Auto Start Stop. On my 335i the engine stop and start worked flawlessly and was very predictable. Without exaggeration it would work on 95% or more of the stops I would make provided car was up to temperature and outside temperature wasn't freezing.

Now with the 535d even with engine up to temperature and outside temperature being nice it only comes on less than 50% of the stops.

Any theories on why? One of my favorite features in these modern BMW cars is the stop start and I am very disappointed the 535d turned off less than 50% of the time vs the 335 which shut off at every stop.

Thanks.

[AP]

As you know the manual lists around 10 reasons why ass may not kick in. Perhaps the battery is the most likely?

Not sure how to do it myself but the hidden menu on the dashboard might list what the battery charge might be?

Try turning ass off for a few journeys to give the battery a chance to get fully charged up and see if that makes a difference- thats my suggestion

[Stifler]

I had the same issue... When I bought my F10 the temperature outside was around 10-12 C degree, besides my car spent like 2 months just standing and the battery was pretty low (I had it on my display). After some time when the battery has been charged and the outside temperature increased, the Start Stop turns on most of the time, what really p….. me off. So this will be the first thing to code... (I want it to stay in the last position used - which is off )
By the way... I've been always taught that turbo needs to be cooled down after a ride and the engine MUST NOT be turned off, just after the car is stopped. It needs to run at idle for a while. So how about the Start Stop function? I had a friend who fried his turbo after running for 400 km at the highway at 150 kmh at summer. After he stopped at the gas station he immiediately turned his engine off... The turbo literally just melted... (This was a VW Passat but anyway...)

[Fox530]

It's a diesel engine, they are more thermally efficient than petrol engines and as a result take longer to warm up - meaning it'll be longer before start-stop kicks in.

What do you think of your 535d against the 335i? How is the engine noise in the cabin when in traffic etc?

[CmdllbF11]

Originally Posted by RASHID007

As the title says (sorry couldn't resist wording it that way) I just traded in my F30 335i RWD for a 2014 535d X-Drive. Needed something bigger, quieter and more comfortable.

I LOVE everything about the 535d EXCEPT the Auto Start Stop. On my 335i the engine stop and start worked flawlessly and was very predictable. Without exaggeration it would work on 95% or more of the stops I would make provided car was up to temperature and outside temperature wasn't freezing.

Now with the 535d even with engine up to temperature and outside temperature being nice it only comes on less than 50% of the stops.

Any theories on why? One of my favorite features in these modern BMW cars is the stop start and I am very disappointed the 535d turned off less than 50% of the time vs the 335 which shut off at every stop.

Thanks.

The ASS will not kick in if the ambient temperature is not at peak e.g. If A/C set to lowest (16oC) the engine will continue to run to maintain ambient. Try messing around with ambient temperature and see if that makes a difference.

[ErnestHouse]

Originally Posted by RASHID007

Traded F30 335i for F10 535d and ASS is killing me.

Isn't this what the active front seats are for?

[Sjoerd]

I have a (EU) 535d but my 'ASS' works well. Probably 98% working rate.

[AVIMAX]

I have the exact same experience with my 535xd. I cannot figure out the logic. Some days it kicks in after 2 mins of driving, the next day with the exact same weather it doesn't kick in at all. It can be working perfectly for 30 mins of driving, but then I'll stop, turn off the car, get back in and start driving again 5 mins later and it won't kick in anymore for the rest of the drive. In the winter it rarely works, but there were days that were -20C and out of the blue at a stop light the engine would turn off, so the minimum outside temperature seems to be very low. I find around 5C-10C is when it works most consistently. Any warmer or cooler and it is sporadic. In comparison, any petrol loaner I've had always worked very consistently and predictably, not at all like my car. I mentioned it to the dealer, they gave me the usual answer, it's supposed to work like that. They did code it to remember the last setting however.

[Bimmer5]

I am looking forward to my first service so I can get it coded to last setting (off) as well.

[silberma]

I routinely turn off the ASS. I rather burn a few cents of gas more than be stuck later with a expensive worn out starter replacement. However, if I has a leased car I would leave it on all the time.

[RASHID007]

Originally Posted by AP

As you know the manual lists around 10 reasons why ass may not kick in. Perhaps the battery is the most likely?

Not sure how to do it myself but the hidden menu on the dashboard might list what the battery charge might be?

Try turning ass off for a few journeys to give the battery a chance to get fully charged up and see if that makes a difference- thats my suggestion

Thanks for the tip. I have disabled the ASS and will leave it that way for a week to see if it helps fully charge battery.

Didn't know there was a menu where I could see battery charge level. Anyone know where to find it?

Thanks.

[RASHID007]

Originally Posted by Stifler

I had the same issue... When I bought my F10 the temperature outside was around 10-12 C degree, besides my car spent like 2 months just standing and the battery was pretty low (I had it on my display). After some time when the battery has been charged and the outside temperature increased, the Start Stop turns on most of the time, what really p.. me off. So this will be the first thing to code... (I want it to stay in the last position used - which is off )
By the way... I've been always taught that turbo needs to be cooled down after a ride and the engine MUST NOT be turned off, just after the car is stopped. It needs to run at idle for a while. So how about the Start Stop function? I had a friend who fried his turbo after running for 400 km at the highway at 150 kmh at summer. After he stopped at the gas station he immiediately turned his engine off... The turbo literally just melted... (This was a VW Passat but anyway...)

How did you get the battery charge level on your display?

Thanks.

[RASHID007]

Originally Posted by Fox530

It's a diesel engine, they are more thermally efficient than petrol engines and as a result take longer to warm up - meaning it'll be longer before start-stop kicks in.

What do you think of your 535d against the 335i? How is the engine noise in the cabin when in traffic etc?

I notice that it does take longer to warm up. But even after warm up it doesn't shut off at stop on more than 50% of occasions.

The diesel is very refined and if I hadn't spent time with the gasoline inline 6 I wouldn't have noticed the difference. It does NOT sound sporty at all vs the engine in the 335. But to be fair the 335 exhaust and other factors played a role. That car sound phenomenal all the time and especially in sport mode at WOT it makes a boom/fart noise between shifts.

The 335 was way faster, sounded way better and handled way better. But other than those 3 things the 535d blows it away. Amazingly comfortable and quiet. Better looking and bigger and more classy and better features and the diesel is amazing. I am averaging 30+ mpg so far.

First time I filled it up the dash range said 1009km to empty!

Love it. If I inly the ASS would work I would get even better mileage.

[RASHID007]

Originally Posted by CmdllbF11

The ASS will not kick in if the ambient temperature is not at peak e.g. If A/C set to lowest (16oC) the engine will continue to run to maintain ambient. Try messing around with ambient temperature and see if that makes a difference.

I normally keep temp at 21 or 24 Celsius depending on weather.

I will try and shut it off and see of that makes a difference.

Thanks.

[RASHID007]

Originally Posted by AVIMAX

I have the exact same experience with my 535xd. I cannot figure out the logic. Some days it kicks in after 2 mins of driving, the next day with the exact same weather it doesn't kick in at all. It can be working perfectly for 30 mins of driving, but then I'll stop, turn off the car, get back in and start driving again 5 mins later and it won't kick in anymore for the rest of the drive. In the winter it rarely works, but there were days that were -20C and out of the blue at a stop light the engine would turn off, so the minimum outside temperature seems to be very low. I find around 5C-10C is when it works most consistently. Any warmer or cooler and it is sporadic. In comparison, any petrol loaner I've had always worked very consistently and predictably, not at all like my car. I mentioned it to the dealer, they gave me the usual answer, it's supposed to work like that. They did code it to remember the last setting however.

Thanks for the feedback.

So are we to assume that diesel is different and won't turn off as often. I see a 98% turn off rate above.

Anyone else with diesel that can provide feedback on their ASS function?

Thanks.

[RASHID007]

When I asked dealer they said 2 things:

1. Let battery charge as it sat on lot for a while.

2. 2014 has different algorithm than my 2012 335i. In 2012 it wasn't checking battery charge as a factor. Now it does as this is the better way for BMW to do it.

Thoughts on #2?

Thanks.

[RASHID007]

I wonder if there is a way to code the factors that it considers to be more aggressive in shutting off rather than staying on so often.

[raleedy]

Nice to see that someone wants it to work more -- so many owners just shut it off because they "don't like it".

[Grover432]

Originally Posted by RASHID007

Thanks for the tip. I have disabled the ASS and will leave it that way for a week to see if it helps fully charge battery.

Didn't know there was a menu where I could see battery charge level. Anyone know where to find it?

Thanks.

Rather than wait a week, why don't you trickle charge the battery overnight an then take the car for a test drive? That will eliminate battery "state of charge" from the equation.

[AP]

For the record, I've dug out my manual for my car (2012 diesel model) and these are the circumstances when ASS will NOT kick in

Ambient temperature below +3c / 37F

high outside temperature and operation of air conditioning

interior not heated or cooled to the desired temperature

engine is not at operating temperature

Sharp steering angle or steering operation

after reversing

Condensation when the automatic air conditioning is switched on

Vehicle battery in a low state of charge

Bonnet is unlocked

HDC is activated

parking assistant is activated

stop /go traffic

Gear selector in n: or S/M position

[Stifler]

Originally Posted by RASHID007

How did you get the battery charge level on your display?

Thanks.

I had a warning notice: "Battery low. Charge the battery" or something similar...

[ezmaass]

Call me a skeptic, but I'm not convinced the Auto Stop/Start feature is at all an economical function of the car. Does it really save any considerable amount of gas to warrant the strain it places on the motor and starter?

I have to believe that the cost of wear-and-tear is far greater than the amount of fuel saved. It reminds me of a study I saw many years ago that analyzed the cost of a kilowatt hour against that of the additional strain (and hence premature failure) on a lightbulb from flicking it on/off for a short period where you left the room. The result was a certain "threshold" of time where if under, it made sense to leave the bulb on, and if over made sense to shut it off. It makes me believe there must be a similar threshold in play here, too... but instead of a $0.60 lightbulb, we're talking about a very expensive piece of complex machinery.

Beyond the question of the ROI and whether it makes economic sense or not, I just don't like the feeling. The car shakes ever so slightly each time the engine needs to come alive... and it's not a confidence-inspiring feeling to have your car shaking back to life just when you're getting ready to press the accelerator down to move-off from a stop. I can't say I like the sensation.

For the above reasons, I leave my ASS turned OFF. If someone could convince me there's a positive ROI, I *may* find my way to overlook the latter pet peeve regarding the awkward shaking sensation.