Cold Start issue (normal?)

[rmanm4]

I don't remember my car having this issue when I bought it new, car now has 1200 miles (still new) and I've noticed a issue only on cold start. I brought it up with my SA and they found no errors or shadow errors.

The issue:

Please listen for the pause in idle at 45 seconds and 55 seconds.

These dead spots you can feel from inside the car.

Once car warms up it's smooth and gone. I'm wondering if this is a wastegate issue or a Vanos/timing issue or totally normal on a S55.

Thanks for any input.

[RKP]

FINALLY! I thought I was the only one with this issue. I took it to the dealership and they couldn't "reproduce" the issue. Additionally, there were no error codes or anything at all. Some days I will hear many pauses back to back but sometimes it will only be a few. It almost feels like a misfire from inside the car. Any idea? It drives me crazy that this is normal according to the dealership.

[rmanm4]

Originally Posted by RKP

FINALLY! I thought I was the only one with this issue. I took it to the dealership and they couldn't "reproduce" the issue. Additionally, there were no error codes or anything at all. Some days I will hear many pauses back to back but sometimes it will only be a few. It almost feels like a misfire from inside the car. Any idea? It drives me crazy that this is normal according to the dealership.

Good to know I don't need to make a tin foil hat!

Yes, some days it's more and others you feel nothing. It does feel like misfire from side the car!

My SA showed the video to top tech and they said it's not a issue as no error codes or shadow/secondary codes.

It would be nice to have a few other people check for this on a overnight cold start.

[horsepower_and_hounds]

Oh yea...have had that ghost in the past. I never paid much attention to it. Never had any issues and am at 38k now

[Zomboss]

I hear this every now and then. I thought it was a bug in the Active Sound SW and didn’t really pay much attention to it.

[rmanm4]

Ok, so we can classify this as a S55 characteristic?!?! The N55 in my X5 does not do it at all.

[horsepower_and_hounds]

Originally Posted by rmanm4

Ok, so we can classify this as a S55 characteristic?!?! The N55 in my X5 does not do it at all.

That would be a yes.......

[Kilabyte]

Spark plugs. Worked for me.

[coldfish]

Originally Posted by rmanm4

Ok, so we can classify this as a S55 characteristic?!?! The N55 in my X5 does not do it at all.

Originally Posted by rmanm4

Ok, so we can classify this as a S55 characteristic?!?! The N55 in my X5 does not do it at all.

spark plug issue. Mine was much worse last year when it happened and even popped up engine light saying misfires on cylinders. (engine light will only be on when misfire count is over certain limit)

I bought two sets of new OEM spark plugs from dealership to completely solve it. I feel OEM spark plugs have some QC issue. First set of new plugs still gave me same problem, second set solved it.

mine happened at around 4000km. new car as well

[FriedPiston]

Sounds like a normal S55 cold start.

[rmanm4]

Originally Posted by coldfish

spark plug issue. Mine was much worse last year when it happened and even popped up engine light saying misfires on cylinders. (engine light will only be on when misfire count is over certain limit)

I bought two sets of new OEM spark plugs from dealership to completely solve it. I feel OEM spark plugs have some QC issue. First set of new plugs still gave me same problem, second set solved it.

mine happened at around 4000km. new car as well

Originally Posted by Kilabyte

Spark plugs. Worked for me.

Originally Posted by coldfish

spark plug issue. Mine was much worse last year when it happened and even popped up engine light saying misfires on cylinders. (engine light will only be on when misfire count is over certain limit)

I bought two sets of new OEM spark plugs from dealership to completely solve it. I feel OEM spark plugs have some QC issue. First set of new plugs still gave me same problem, second set solved it.

mine happened at around 4000km. new car as well

I would agree on spark plug issue if it rough idled after cold start. My F82 is only a year old with 1200 miles on it. It only has this inconsistent idle on a overnight cold start for the first minute before it drops under 700 RPM.

[coldfish]

Originally Posted by rmanm4

I would agree on spark plug issue if it rough idled after cold start. My F82 is only a year old with 1200 miles on it. It only has this inconsistent idle on a overnight cold start for the first minute before it drops under 700 RPM.

Right. I am pretty sure it actually happens on many F80/F82 cars. Since many ppl just start and go, it is hard to be noticed once the car starts rolling.

OEM spark plugs definitely have some issue. In my two sets of new OEM spark plugs, there are about 3 plugs causing misfires even though they are brand new.

Your dealership probably won't cover the cost if they cannot reproduce it or get any error/code. In my case, I paid out of pocket.

[rmanm4]

Good to know. Will have to look into BMW spark plugs and see if BMW changed part numbers or supplier. I would imagine they know of a spark plug issue!

[CJStevens]

I think it's just a normal thing while it's warming up. I have brand new plugs about 2xxx miles ago and I turned off the cold start on mine and sometimes it will do a little pauses after it's been sitting and I start it up. I attribute it to it being a high horsepower turbo engine and it just trying to get everything evened out while it's cold. Never had any actual issues from it and doesn't seem to throw any codes. Let it warm up then let it rip!

[rmanm4]

It sure seems that way.

On cold start the waste gate opens up to allow cats to farm up faster. There is no secondary pump like on the non turbo engines to warm up cats. This might just be a characteristic of the waste gate flap vibrating when wide open. Once the gates close rpm drops to under 700, the idle is smooth. I don't think it's a spark plug or Vanos issue. For sure a waste gate characteristic! If waste gate is out of spec you get codes right away, so nothing to worry about.

[N1rve]

I think my 2019 always starts up like this. It's like the car skips a beat. I am currently at 20346 miles and it's always done that for me since new. No codes, nothing. I do have my major 3 year service coming up to replace sparkplugs though in a few months.

[rmanm4]

Originally Posted by N1rve

I think my 2019 always starts up like this. It's like the car skips a beat. I am currently at 20346 miles and it's always done that for me since new. No codes, nothing. I do have my major 3 year service coming up to replace sparkplugs though in a few months.

Let us know if it went away after spark plug change. I doubt it as it feels like a waste gate thing but keep us informed!

[DDD31]

Mine does the same thing. When the car was brand new, it threw a check engine light and codes for a misfire. Dealer replaced some spark plugs and check engine light or codes have not returned in almost 3 years but car still does what yours does on a cold start.

[OvergrownTony]

Check spark plug gap.

[NYG]

Reading all these replies is painful.

There's absolutely nothing wrong with your car - welcome to the world of direct injected engines.

You're running RICH AF on cold start and your O2 sensors won't start communicating until they heat up.

[rmanm4]

Originally Posted by NYG

Reading all these replies is painful.

There's absolutely nothing wrong with your car - welcome to the world of direct injected engines.

You're running RICH AF on cold start and your O2 sensors won't start communicating until they heat up.

Totally understand that, but why doesn't it show up on the N55? I've had many years of experience with M54, S54, N52, N55 and now S55 and only have seen this on the S55. Is the timing on cold start that much advanced to run RICH? Also running rich is cooler then running lean, lean would have higher exhaust temps for heating up cats.

[FriedPiston]

Originally Posted by rmanm4

Totally understand that, but why doesn't it show up on the N55? I've had many years of experience with M54, S54, N52, N55 and now S55 and only have seen this on the S55. Is the timing on cold start that much advanced to run RICH? Also running rich is cooler then running lean, lean would have higher exhaust temps for heating up cats.

The N55 have both O2 sensors in the same catlytic converter. This is still a normal cold start condition for the S55, even with with the cold start sequence disabled. Feel free to chase this down as a phantom issue, it surely won't hurt anything.