[Jayrhee7]

So I've been posting and tackling this for quite some time, and my mechanic is saying he's not too sure either.

I have 2016 M2 with the following mods:
• AA Catted DP
• CSF FMIC
• FTP Charge Pipe
• TurboSmart Diverter Valve
• BM3 OTS Stage 2 93oct

So this all started when I changed out the spark plugs and ignition coils. The car was stalling right after starting up or it would shake and struggle at idle, feeling like it's on the verge of stalling. (All of this happens when the cars already warmed up, and you start the car)

I took it to my mechanic, and he sort of resolved it by switched the plugs out for new NGK's, and so far it only stalled twice, but it's always shaking and struggling for about 5-8 seconds, especially if the car starts when the A/C fan is off, and then it seems fine.
Sometimes, when I start the car, the RPM's will also spike up out of nowhere, and then settle back down. Very quickly. No codes at all.

Here are a couple videos of the start ups. It may be hard to hear but it really does start up and then settle down almost as if it's on the verge of stalling.

Anyone have any idea what's going on? I may put the old ignition coils back on to see if that was the issue. Other than that, I'm thinking about MAF sensor, MAP sensor, O2 sensor, DP, HPFP, Fuel Injectors, or possibly even Valve Cover Gasket.

https://youtube.com/shorts/iR21Gjqjir4?feature=share

https://youtube.com/shorts/mSUmLUGGLX8?feature=share

https://youtube.com/shorts/YDgRwD4YRmI?feature=share

https://youtube.com/shorts/B6QMPuaOKYo?feature=share

[nioh_lbbm2]

Is cold start off? Try keeping it on. One of the most common things suggested in the BM3 fb group for people having similar startup issues as you

[Jayrhee7]

Originally Posted by nioh_lbbm2

Is cold start off? Try keeping it on. One of the most common things suggested in the BM3 fb group for people having similar startup issues as you

I have not messed with that option in configurations menu. I only have:
"Exhaust Burble Type" toggled Custom
"GTS Startup Roar" toggled on
"Catalytic Monitors (CEL)" toggled off.

[nioh_lbbm2]

Originally Posted by Jayrhee7

I have not messed with that option in configurations menu. I only have:
"Exhaust Burble Type" toggled Custom
"GTS Startup Roar" toggled on
"Catalytic Monitors (CEL)" toggled off.

If you're stage 2 then by default cold start is disabled on the map. I would go and set it to enabled and re-flash and see how it runs.

[ZM2]

Try resetting adaptations.

[VisualEcho]

Originally Posted by nioh_lbbm2

Is cold start off? Try keeping it on. One of the most common things suggested in the BM3 fb group for people having similar startup issues as you

How is it that I've had my car 2 years and have been straining at the bit every day of those 2 years until my warranty is up (December) so I can get BM3, and I'm just hearing of this now?? Disabling cold-start is one of the biggest reasons I want BM3. MHD is looking better and better.

[ZM2]

Originally Posted by VisualEcho

How is it that I've had my car 2 years and have been straining at the bit every day of those 2 years until my warranty is up (December) so I can get BM3, and I'm just hearing of this now?? Disabling cold-start is one of the biggest reasons I want BM3. MHD is looking better and better.

This is actually an issue exhibited by untuned & tuned N55’s across all platforms, and likely isn’t BM3 or MHD related. Just check out the F30 forums and all the stuff they’ve tried.

Turning cold start back on doesn’t solve the problem, it just helps mask it by running the revs up so the car doesn’t instantly die.

The best luck I’ve had addressing this problem is by reseting adaptations, and then I can leave cold start off without any issues.

[VisualEcho]

Originally Posted by ZM2

This is actually an issue exhibited by untuned & tuned N55’s across all platforms.

The best luck I’ve had addressing this problem is by reseting adaptations, and then I can leave cold start off without any issues.

Thanks for that, never heard of it until now.

[Wolfman’s Brother]

Sorry to hear this. Please keep this thread updates if you get it resolved.

[nioh_lbbm2]

Originally Posted by ZM2

This is actually an issue exhibited by untuned & tuned N55's across all platforms, and likely isn't BM3 or MHD related. Just check out the F30 forums and all the stuff they've tried.

Turning cold start back on doesn't solve the problem, it just helps mask it by running the revs up so the car doesn't instantly die.

The best luck I've had addressing this problem is by reseting adaptations, and then I can leave cold start off without any issues.

ZM2 is right. It's a strange phenomenon and I don't think even PTF has been able to address this directly. From what I've seen by lurking on the forums/groups it might be related to different climates and the local gas quality. I think I've seen it mostly happen it colder regions but again nothing official from PTF. My car doesn't exhibit this behavior for what it's worth. Located in Cali

[Jayrhee7]

Originally Posted by ZM2

Try resetting adaptations.

Are you referring to this? (Photo)
If so, i tried this a couple times with no difference.

I read somewhere there's another way (I forgot the process) but it's like holding gas pedal down for a certain amount of time and what not.

[Jayrhee7]

Originally Posted by nioh_lbbm2

If you're stage 2 then by default cold start is disabled on the map. I would go and set it to enabled and re-flash and see how it runs.

Did not know this, I'll give it a try. Thank you!

[ZM2]

Originally Posted by Jayrhee7

Are you referring to this? (Photo)
If so, i tried this a couple times with no difference.

I read somewhere there's another way (I forgot the process) but it's like holding gas pedal down for a certain amount of time and what not.

Yup. Try resetting it a couple times on your next drive and then see how the next day’s cold start goes.

[carchrism5]

My car has done this a few times. I noticed it after changing plugs and filter too. I looked on the 2 series page and found a number of people with this issue, under warranty dealers were throwing fuel pumps at them but didn't solve it. Mine seemed to also be correlated to gas quality, every now and then you can get bad gas, I noticed a local Shell V Power station did it to my car and stopped taking that car there for months. Then didn't stall for months, just this week I had my car stall twice on cold start which ironically happened just after filling up at another station.

Also there are people talking about MAF sensors, unplugging and running the car for a bit (more in the 2 series forums) which oddly fixed it for many people. Lastly cleaning MAF sensor.

It is kind of a weird issued and not a fun one to have but hopefully this gives you a little more info and things to check.

[Jayrhee7]

Originally Posted by carchrism5

My car has done this a few times. I noticed it after changing plugs and filter too. I looked on the 2 series page and found a number of people with this issue, under warranty dealers were throwing fuel pumps at them but didn't solve it. Mine seemed to also be correlated to gas quality, every now and then you can get bad gas, I noticed a local Shell V Power station did it to my car and stopped taking that car there for months. Then didn't stall for months, just this week I had my car stall twice on cold start which ironically happened just after filling up at another station.

Also there are people talking about MAF sensors, unplugging and running the car for a bit (more in the 2 series forums) which oddly fixed it for many people. Lastly cleaning MAF sensor.

It is kind of a weird issued and not a fun one to have but hopefully this gives you a little more info and things to check.

Yeah I think I stumbled on some of those threads while searching the forums.
I usually pump gas at Wawa, Kangaroo, and Shell. It may be the MAF sensor because I did get these codes:
• 10B101 Ambient Temp Sensor: Short Circuit to Positive

• 108001 Intake air Temperature Sensor, electrical: Short Circuit to B+

• 108010 Intake-air temperature sensor, electrical:signal not plausible.

They have since disappeared but something has to be wrong if they popped up.

[ZM2]

Sounds like replacing the MAF fixes this for sure, but haven’t tried it. Apparently they don’t last forever.

Anyone have success with that?

[Jayrhee7]

Originally Posted by ZM2

Sounds like replacing the MAF fixes this for sure, but haven't tried it. Apparently they don't last forever.

Anyone have success with that?

I'm hoping it works!! Unfortunately, I didn't start the car recently for about 4 days, and when I got back, it almost stalled on start up but is running fine now. Hoping that was just a minor glitch but hopefully the MAF is all I need!! I've had the MAF unplugged the last few weeks and start ups are a lot better than when it was plugged in

[ZM2]

Originally Posted by Jayrhee7

I'm hoping it works!! Unfortunately, I didn't start the car recently for about 4 days, and when I got back, it almost stalled on start up but is running fine now. Hoping that was just a minor glitch but hopefully the MAF is all I need!! I've had the MAF unplugged the last few weeks and start ups are a lot better than when it was plugged in

https://www.fcpeuro.com/products/bmw...sor-0280218279

I think they just degrade or get dirty over time. If I’m making the effort to clean it, I’m just going to replace it with new.

[Jayrhee7]

Originally Posted by ZM2

https://www.fcpeuro.com/products/bmw...sor-0280218279

I think they just degrade or get dirty over time. If I'm making the effort to clean it, I'm just going to replace it with new.

Yeah I tried cleaning mine but didn't work. At least it's not too serious to replace 🥴 thanks for the link!!

[VCpowered]

Hello, I start to have this problem after change filter and plugs on bmw, so my question, can't this be the plug gap that is not correct? Normally the plugs go from box to motor and no one check that.

[Jayrhee7]

Originally Posted by VCpowered

Hello, I start to have this problem after change filter and plugs on bmw, so my question, can't this be the plug gap that is not correct? Normally the plugs go from box to motor and no one check that.

It could be an issue, but for me, I checked the gaps before installing them. Also, when my mechanic decided to switch out the plugs again, he gapped them as well.

[ZM2]

I’m changing my MAF couple weeks. Will let you all know if that helps.