[jcl89]

2015 M235i ZF8, CPO with 30.5K miles (got it in January with 28.3K miles). 100% stock, I'm the second owner. Based in CA. Previous car was a 2014 Focus SE.

Did some research and read that apparently this can happen with the M235i and that you should wait a few seconds on cold start to let the revs settle. I wasn't aware of this, so ran into two surprises in the past month:

First instance (40-50 degrees F outside), I cold started, immediately reversed, and revs jumped, engine shut off, car went into park (like this video:

). Restarted car and all was fine.

Second instance (garage today, 50-60 degrees F), I cold started, immediately reversed, revs jumped. Put it back in park, reversed and all was fine.

Two questions:

1. Is this worth bringing into service for inspection?

2. Now I'm aware that I should let the car sit 10secs or so before reversing, but is there any damage done to the engine in not doing that consistently for ~2200 miles?

I drive 42 miles round trip for work each day, and mix in about 100 miles of fun driving on the weekend. Mix of comfort and sport mode.

[Dylan86]

The computer is probably cutting the engine back to not allow any load until it's past the start-up period (20-30 secs?). I don't think you could have damaged anything, however it's always a best practice to wait for your RPMs to drop before driving.. If your concerned, I'd take it in for service and see what they have to say.

[jcl89]

Originally Posted by Dylan86

The computer is probably cutting the engine back to not allow any load until it's past the start-up period (20-30 secs?). I don't think you could have damaged anything, however it's always a best practice to wait for your RPMs to drop before driving.. If your concerned, I'd take it in for service and see what they have to say.

Cool, thanks Dylan. I'm taking it in tomorrow for a quick look.

[sectachrome]

Sounds weird to me. I can't imagine a 2015 BMW needing to wait for some certain period of time before putting it into gear. Every other non car person is doing exactly this, just starting the car and pulling away without a second thought. They're not thinking about if they should wait until the RPMs drop. I doubt you damaged something but it doesn't sound normal for the engine to stall like that.

[moldcad]

And yet it happened to me twice, as well - not so much stalling, but jerky reversing due to rpm fluctuations...

Piotr

[jcl89]

Hey Piotr, saw your thread - did you ever figure out the cause?

Btw, cool to see you're from Poland - visited Gdansk/Gdynia for 2 weeks for work before.

[Spydeputy]

I never take my engine above ideal for the first 30 seconds after a cold start. Just letting the oil get moving all around the engine first.

[moldcad]

Originally Posted by jcl89

Hey Piotr, saw your thread - did you ever figure out the cause?

Btw, cool to see you're from Poland - visited Gdansk/Gdynia for 2 weeks for work before.

Hi!

No, never - it just went away... Like others, I never demand too much from the completely cold engine, but letting the car roll out of the garage without even touching the gas pedal (just releasing the brakes) cannot harm anything, so I still do it even at -25C outside, haha.

How did you like it here in Poland?

Piotr

[jcl89]

Originally Posted by moldcad

Hi!

No, never - it just went away... Like others, I never demand too much from the completely cold engine, but letting the car roll out of the garage without even touching the gas pedal (just releasing the brakes) cannot harm anything, so I still do it even at -25C outside, haha.

How did you like it here in Poland?

Piotr

Ah got it, is your's the ZF8 or manual? And how did it stall?

Poland was great, looking forward to coming back again. Saw a good part of the tri city area.

Took my car in today and service advisor said I should give it 30 seconds to warm up. He didn't seem worried about it since it only happened once on cold start. Since we're in CA, he said it could also be the fuel since it's slightly diluted to meet emissions standards.

They were able to schedule the 10K oil change service early (I'm at about 7.2K). That includes a "scope check", which I think is a diagnostics.

[jcl89]

Originally Posted by sectachrome

Sounds weird to me. I can't imagine a 2015 BMW needing to wait for some certain period of time before putting it into gear. Every other non car person is doing exactly this, just starting the car and pulling away without a second thought. They're not thinking about if they should wait until the RPMs drop. I doubt you damaged something but it doesn't sound normal for the engine to stall like that.

I just remembered that the engine shut off and the car went into park. Is that still considered a stall? I wonder if a true stall would require the car to still be in reverse with engine off.

Actually found a video on Youtube:

[Fabspeed Motorsport]

It's always good to start the car and allow the cold start revs to drop before you start driving. It only takes about 20 seconds for it to happen.

[dtcoff]

The video is mine actually.

The issue is on cold starts the revs jump around from less than 500 to 2,000 before settling down after about 10 secs. If the car is put in gear (ZF8) during this time, it can stall.

I've had this issue since 6 months after new and has been to the dealer many times and BMW have created a PUMA for it. They keep updating the software and putting a fuel cleaner in the tank. Fixes it for about a month and then comes back. Last time they replaced the crankcase sensor too and it's been a lot better, but it still does it to a lower degree and not every cold start, although it's summer in Australia now and it's been a very hot one with most days in January around 100F. I'm waiting to see what happens when it starts to cool down overnight.

[jcl89]

Originally Posted by dtcoff

The video is mine actually.

The issue is on cold starts the revs jump around from less than 500 to 2,000 before settling down after about 10 secs. If the car is put in gear (ZF8) during this time, it can stall.

I've had this issue since 6 months after new and has been to the dealer many times and BMW have created a PUMA for it. They keep updating the software and putting a fuel cleaner in the tank. Fixes it for about a month and then comes back. Last time they replaced the crankcase sensor too and it's been a lot better, but it still does it to a lower degree and not every cold start, although it's summer in Australia now and it's been a very hot one with most days in January around 100F. I'm waiting to see what happens when it starts to cool down overnight.

Ah, got it. So if you cold start, wait a few seconds for revs to settle down (let's say 10), put in reverse, the car still stalls?

[GioM2Comp]

I have a similar thing happen to me. When I cold start the car, the rpm's are normal for the first 1-2 seconds, then drop to about 500 and quickly jump to about 2000 before settling.
This has happened from when the car was brand new. It now has over 20k miles.
It happens random. It might happen a few times a week then nothing for weeks or months and then happens again.
I have a 6mt.

[Sportstick]

Originally Posted by jcl89

1. Is this worth bringing into service for inspection?

Maybe just a change of sequence habit. Start the car first. Then put on your seat belt, adjust radio/sound source for your preference, climate control if necessary. Look around for first glimpse of traffic/pedestrians. By then, you can engage gear and should be able to take off without problem.

[dtcoff]

Originally Posted by jcl89

Ah, got it. So if you cold start, wait a few seconds for revs to settle down (let's say 10), put in reverse, the car still stalls?

No, it doesn't stall if I wait for the revs to settle down, only whilst it's jumping around and goes very low.

[German1967]

Originally Posted by GioM235

I have a similar thing happen to me. When I cold start the car, the rpm's are normal for the first 1-2 seconds, then drop to about 500 and quickly jump to about 2000 before settling.
This has happened from when the car was brand new. It now has over 20k miles.
It happens random. It might happen a few times a week then nothing for weeks or months and then happens again.
I have a 6mt.

Happens to me too. 2015 M235 with ZF8.
It's a bit unsettling when this happens and you reverse out of garage... The car speeds up quickly if not foot on brake. Scared the sh.. out of me first time it happened.