Cold Start Idle Problem

[B.Hahn]

Looking for some help on my 2017 M4 ZCP. When Cold starting on low temp days the vehicles rpm fluctuates, it only happens on cold starts when outside temp is below 60 or so. The RPM fluctuates like it wants to stall for about 30 seconds and returns to normal. It never actually stalls, and if I put it straight to Drive everything is normal, after full warm up it idles fines. Any help would be greatly appreciated. Thanks in Advance. Below is the link to the video, and also an attached photo since I haven't shared my vehicle on here yet.

https://youtu.be/GY6nJG5WJ-s

[jpy1980]

Do you have an intake? Or maybe your maf is dirty? When’s the last time you changed your spark plugs?

[B.Hahn]

Dinan Cold Air Intake, just over 11k miles on it so super low still, so I wasn't thinking spark plugs. I was leaning towards Vanos being the issue, but wanted input.

[SoupPlug]

This used to happen with my rktunes intakes. Chokes out for a bit and then is fine within half a minute. I cleaned my MAF sensors and made sure they were extra snug when I plugged them back in. It fixed the issue 95% of the time

[B.Hahn]

I disconnected, cleaned, and reconnected the MAF sensors. Same issue on start up this morning. Temp is 42 outside today.

[Tommy L Garage]

This is related to your cold start delete in your tune.

[B.Hahn]

Tommy, the vehicle doesn't have cold start delete on the tune or I would totally agree. I just edited the video to make it shorter to show the issue, ill upload a full cold start, the RPM fluctuations start around the 1 minute mark after the vehicle settle from the cold start. Complete list of mods are:

Dinan Stage 3 ECU
Dinan Carbon Fiber Intake
Dinan Heat Exchanger
Dinan X Pipe
Dinan Coil Overs

https://youtu.be/rYvrIjtXGmQ

[B.Hahn]

Also this does not happen when it is warm outside, lets say anything over 70 degrees, and it is more pronounced the colder it gets, the rpm fluctuations are around 300-500 when below 30 degrees. Also we moved and I am at a higher altitude now, from sea lever to around 5k feet.

[rborane]

I have the Dinan intake as well and my car idles perfectly with BM3 stage 1. Sounds like it could be a plug issue

[behindthen0thing]

Mine does the same. I'd venture to almost say it's normal

[B.Hahn]

I keep the tune in Bypass mode 99% of the time with the ECU.

Crank Hub and Charge Pipe Upgrade is scheduled for August it was schedule to be done this month but due to Military restricted movement for 60 days it had to be changed, trying to correct this issue before that work takes place.

[Tommy L Garage]

Are you sure the cold start delete is not there?
Cold start RPM should be above 1k. Unless I’m missing something.

[behindthen0thing]

I've got a tune, and eventuri intakes. When it's cold outside my car runs like an old 60's muscle car for about 15-20 seconds.

I had the plugs changed as scheduled and it helped it slightly, but nothing huge.
I read somewhere that the aftermarket intakes cause this pretty commonly but I'm not entirely sure.

[B.Hahn]

Tommy, unless the Dinan Stage 3 ECU tune deletes it, which I don't believe it does, but I could be wrong. But besides the mods listed above and cosmetic upgrades, nothing else has been done. The second video I linked should shows the cold start from this morning, granted the vehicle is always in the garage which is slightly warmer than outside but the rpms are above 1k for a short period.

[B.Hahn]

The wife 2017 440 had a similar issue shortly after we moved from California to New Mexico. The 4 series was parked outside and during the winter when we first moved here on the initial start up with would fluctuate RPMs like wanting to stall but it would eventually stall after 30 seconds. BMW replaced the Vanos and it cleared up.

[kumkeet]

I have an eventuri. Same thing happened after I changed the intake. I wouldn't worry about it. Just don't let it idle for too long and drive off soon after start up.

It 'chokes' but doesn't stall.