Rough idle on evening startup...

[gfisher99]

Just curious if anyone else has the same symptom as me.

When I start my car from an overnight stay in the garage, everything is normal, cold start procedure goes for about a minute - no worries.

When I go to start my car after sitting for 9 hours at work, the cold start routine goes for about the same amount of time, but about 10 seconds before it's about to end, the idle jumps up and down by about 150-300RPM and feels like it's going to stall sometimes - runs really rough. Once the cold start routine is over, its fine again.

I have read about the fuel tank breather valve causing somewhat similar issues, but mine only does it after a previous start that was 6-10 hours previous and it has never actually stalled.

No codes at all.

Anyone know what could cause this? I can't really remember if it's done this for the whole 2 years I've owned it mainly because I worked from home every day until recently and rarely started my car twice in one day staggered by many hours.

2011 w/48K miles.

[SYT_Shadow]

Idle control valve?

[EJT86]

ICV should throw codes and a fuel breather is $80 May as well just replace it because most of the time it’s the fuel breather

[gfisher99]

Originally Posted by EJT86

ICV should throw codes and a fuel breather is $80 May as well just replace it because most of the time it’s the fuel breather

May just do that. Have seen people replace this when they have issues after filling up, which I never have, but I guess it's worth a shot.

[EJT86]

Originally Posted by gfisher99

May just do that. Have seen people replace this when they have issues after filling up, which I never have, but I guess it's worth a shot.

its not always after filling up. i got it "randomly" if its failing it'll happen anytime the car is scheduled to purge the vapor can which isnt only after filling up

[marcster]

Originally Posted by gfisher99

Just curious if anyone else has the same symptom as me.

When I start my car from an overnight stay in the garage, everything is normal, cold start procedure goes for about a minute - no worries.

When I go to start my car after sitting for 9 hours at work, the cold start routine goes for about the same amount of time, but about 10 seconds before it's about to end, the idle jumps up and down by about 150-300RPM and feels like it's going to stall sometimes - runs really rough. Once the cold start routine is over, its fine again.

I have read about the fuel tank breather valve causing somewhat similar issues, but mine only does it after a previous start that was 6-10 hours previous and it has never actually stalled.

No codes at all.

Anyone know what could cause this? I can't really remember if it's done this for the whole 2 years I've owned it mainly because I worked from home every day until recently and rarely started my car twice in one day staggered by many hours.

2011 w/48K miles.

Hi there,

I have the same situation as yours - can you provide an update if you resolved your issue?

Thanks.

[gfisher99]

Originally Posted by marcster

Hi there,

I have the same situation as yours - can you provide an update if you resolved your issue?

Thanks.

Still have not figured it out, still happens every day. So hot out now that I turn the AC on right away and that pretty much eliminates it for now. Once it cools off, it will be back at it.

[EJT86]

Originally Posted by EJT86

ICV should throw codes and a fuel breather is $80 May as well just replace it because most of the time it’s the fuel breather

Already presented the solution

[M3Comet]

I've just purchased a 2013 and noticing a similar issue. My friends 2009 does the same thing though, from what I've gathered it's a trait of the engine. I am used to it happening at random times/temperatures, so embracing that it is an imperfect beast with a personality that is sometimes cranky when it wakes up!

[Solo_M_Tech]

I've seen cars with worn and failing spark plugs create idle and start up issues but the car runs perfectly fine at part and wide open throttle (after the car is warmed up a bit). Which sometimes will throw codes, and sometimes not. It may be time for a tune up.

[M3Comet]

Originally Posted by gfisher99

Still have not figured it out, still happens every day. So hot out now that I turn the AC on right away and that pretty much eliminates it for now. Once it cools off, it will be back at it.

Did you replace the fuel breather like you mentioned you may do? If so has it helped?

[gfisher99]

Originally Posted by M3Comet

Did you replace the fuel breather like you mentioned you may do? If so has it helped?

Not yet - I've had the part for ages but haven't had the time to get in there to do it. Trying to hunt down an M2 at the moment for my wife so I can take her F30 328i to use for my daily. That will give me the time to have some downtime on my car and I can get it done at a slower pace with less risk. I will update this post once I've completed it.

[M3Comet]

Hi everyone, I drive my 2013 once or twice per fortnight, I tried the battery charger option with no results.
I then tried the ignition only (not the engine) technique for one minute prior to starting the engine. If it's been a few days, no issues, I started it yesterday for the first time in 14 days, a little burble or two, but stabilised almost straight away. Not a perfect fix, but enough for me.
Maybe a capacitor/battery within the ignition/computer module?