[Stin999]

Originally Posted by thejeremyman9

Yes, i am suggesting you unplug it and start the car with it unplugged. If the issue never occurs with the MAF unplugged it at least gives you a lead that the issue may be MAF related. Without the MAF plugged in the car will default to fuel tables instead of using the MAF to determine the amount of fuel needed.

Originally Posted by thejeremyman9

Yes, i am suggesting you unplug it and start the car with it unplugged. If the issue never occurs with the MAF unplugged it at least gives you a lead that the issue may be MAF related. Without the MAF plugged in the car will default to fuel tables instead of using the MAF to determine the amount of fuel needed.

So…

I did exactly this. Walked into my garage on a cold start, unplugged my MAF sensor, and started the car up with it unplugged.

After continually doing that "stall then catch itself" for a week straight it actually started up perfectly fine and idled great!

What does this mean now? I'm going to let the car idle like the other guy said for a little and then turn it off. Once turned off I'll plug the MAF back in.

I guess my new question is…

What's broken? What needs replacing? Maybe nothing and once I start it tomorrow it will be back to normal again?

All I know is that unplugging and MAF and starting the car with it unplugged cured my issue.

[thejeremyman9]

Originally Posted by Stin999

So…

I did exactly this. Walked into my garage on a cold start, unplugged my MAF sensor, and started the car up with it unplugged.

After continually doing that "stall then catch itself" for a week straight it actually started up perfectly fine and idled great!

What does this mean now? I'm going to let the car idle like the other guy said for a little and then turn it off. Once turned off I'll plug the MAF back in.

I guess my new question is…

What's broken? What needs replacing? Maybe nothing and once I start it tomorrow it will be back to normal again?

All I know is that unplugging and MAF and starting the car with it unplugged cured my issue.

You can try what he said first before doing anything, and check/change your filter as needed while you are at it... Try that stuff and report back.

IIRC you said reflashing also made the problem go away temporarily. If the above doesn't work, you can try resetting adaptations without a reflash and see if that makes it go away as well. If you havent already, you can try cleaning the MAF also. I think replacing the MAF would be the last resort.

[Stin999]

Originally Posted by thejeremyman9

You can try what he said first before doing anything, and check/change your filter as needed while you are at it... Try that stuff and report back.

IIRC you said reflashing also made the problem go away temporarily. If the above doesn't work, you can try resetting adaptations without a reflash and see if that makes it go away as well. If you havent already, you can try cleaning the MAF also. I think replacing the MAF would be the last resort.

Originally Posted by thejeremyman9

You can try what he said first before doing anything, and check/change your filter as needed while you are at it... Try that stuff and report back.

IIRC you said reflashing also made the problem go away temporarily. If the above doesn't work, you can try resetting adaptations without a reflash and see if that makes it go away as well. If you havent already, you can try cleaning the MAF also. I think replacing the MAF would be the last resort.

Happy to report that my 2015 335i started up perfectly this morning. No initial bog at a cold start. Zero issues. Even noticeably shifted and drove A LOT smoother which pleasantly surprised me.

Appreciate all the help on solving this issue.

Considering 2 shops + BMW suggested fuel pump work after observing the cold start bog… spending $160 on a new MAF (if the issue actually comes back) is a real win. Lucky enough to live 30 minutes from FCP Euro as well.

Will update in the future if anything else arises.

Thanks again all - Austin

[Nick335iF30]

Just thought I would add to this again as there seems to be varying resloutions to this issue. After running 2 treatments of TECHRON and switching to SHELL V-Power fuel it only did it once after that. I am not sure if it cleaned up the injector or the pump or both but it was 99% gone vs every single morning.

After tuning to BM3 Stage 2 it has not done it a single time in months. I did however turn off the coldstart warm up as it is a little to loud for when i go to work at 4 a.m. I did not want to be that guy. Not sure if that fixes it I will turn it back on here in the future and see if it comes back. I will run it for a week or two like that and try to remeber to post and see if it returns. Glad we have made some headway on this frustriting issue!

[lens]

Originally Posted by Stin999

Happy to report that my 2015 335i started up perfectly this morning. No initial bog at a cold start. Zero issues. Even noticeably shifted and drove A LOT smoother which pleasantly surprised me.

Appreciate all the help on solving this issue.

Considering 2 shops + BMW suggested fuel pump work after observing the cold start bog… spending $160 on a new MAF (if the issue actually comes back) is a real win. Lucky enough to live 30 minutes from FCP Euro as well.

Will update in the future if anything else arises.

Thanks again all - Austin

Just to add, if you're tuned, you can run MAFless, DME will just calculate air density instead, E series doesn't even use MAF, and apparently air density is better for tuning anyways.

[jcordier]

Originally Posted by Blkjag09

Hey everyone...
Thank you for taking the time to read this.
This just started happening when I start the car in the morning after sitting all night. Car has 74k on it and never had this issue before.
Starts up fine (rpm goes to 1600) but after a few seconds rpms dip( goes down to 500-600) and the car feels like it's going to stall, but immediately goes back up and normalizes and doesn't happen again all day.
I have spoken to multiple bmw technicians and they all say "it's normal" I have read multiple ppl saying they had the same experience.
This does not seem normal since it has never happened in the 74k that this car has been driven.
Once again, thank you for your time

This might sound kind of crazy, but I had the same issue as you. Fairly new plugs as well. I couldn't figure it out. Then decided to add https://www.autozone.com/motor-oil-a...8;gclsrc=aw.ds

To my engine and it cold starts perfectly again. If you haven't solved it. I'd give this a try.

[thejeremyman9]

Originally Posted by jcordier

This might sound kind of crazy, but I had the same issue as you. Fairly new plugs as well. I couldn't figure it out. Then decided to add https://www.autozone.com/motor-oil-a...B&gclsrc=aw.ds

To my engine and it cold starts perfectly again. If you haven't solved it. I'd give this a try.

Just a note that based on watching the liqui moly oil video you should not use their additives if you already run their high additive oil (that FCP sells for example).

[jcordier]

Originally Posted by thejeremyman9

Just a note that based on watching the liqui moly oil video you should not use their additives if you already run their high additive oil (that FCP sells for example).

Thank you. That's good info to know.

[Mdilo]

Originally Posted by Stin999

Happy to report that my 2015 335i started up perfectly this morning. No initial bog at a cold start. Zero issues. Even noticeably shifted and drove A LOT smoother which pleasantly surprised me.

Appreciate all the help on solving this issue.

Considering 2 shops + BMW suggested fuel pump work after observing the cold start bog… spending $160 on a new MAF (if the issue actually comes back) is a real win. Lucky enough to live 30 minutes from FCP Euro as well.

Will update in the future if anything else arises.

Thanks again all - Austin

Did the new MAF completely fix the cold start issue?