Cold Start Misfiring

[hugosf]

Hello all

I own a 2009 E92 M3 DKG , with currently 100K kilometers.

For the last 2 weeks, when the car is stopped for 1-2 days , or all night, in the morning when is start it , the idle got very rought , and misfiring a bit.

Then, 30-40 seconds later it starts getting normal again.

If i start the engine other times during the day after driving it, theres no issue.

Only happens after many hours stopped.

No CHECK lights appear , nothing.

Any hint ?


Regarding modifications, i have Akrapovic Evolution exhaust and Macht Schnell intake filter.

Thanks in advance !!

[s85e90]

My e46 did this and recently, once in a while my e90 has started this.

It doesn't worry me, but once in a while and only very cold, if started and the throttle is touched the car's idle oscillates up and down for a few seconds sounding rough afterwards. It's just the idle and not a miss though.

Seconds later its fine. I don't think its' an issue.

[hugosf]

I see your point.

Mine never did this..

First it started oscilating the rpms , and now misfires a bit

[per]

I had a similar problem 1month ago, one of the valvs in the secondary air system was stuck, and had to be changed, It was a lot of job to change it , the dealer charged me for 8 hours of work.

[coloradoe92m3]

This is called normal cold start

[happos2]

Originally Posted by coloradoe92m3

This is called normal cold start

Misfiring is not normal. Even during cold start, the engine should not misfire. Such wrong information you always give Colorado......

[coloradoe92m3]

What are you calling misfiring? No codes? Misfires trigger codes almost always. So how does one know its a misfire in this case

[s85e90]

Originally Posted by coloradoe92m3

What are you calling misfiring? No codes? Misfires trigger codes almost always. So how does one know its a misfire in this case

A mis will not throw codes always

[happos2]

Originally Posted by coloradoe92m3

What are you calling misfiring? No codes? Misfires trigger codes almost always. So how does one know its a misfire in this case

OP said it misfires. That is what I am calling misfire. Judging only on what the OP said, a misfire is not normal during cold start.

Also, cold start is fairly consistent operation unless something abnormal is happening. You shouldn't see too much of a difference from one day to the next. The OP has over 100k kilometers on his car. I think he would know what cold start is and wouldn't ask the question unless something changed. So before you chime in with worthless comments and sound like you know what you are talking about, you should use your brain and think through possible situations.

OP, sorry for going OT, just trying to limit the amount of mis-information you might get, especially from coloradoe92m3....he has a habit of being wrong and trying to be an expert.
Sounds like it could potentially be something with your secondary air system...

[coloradoe92m3]

Well if you haven't realized what. A Kay person thinks is mis fire likely isn't misfire. Especially since its so rich during cold start. If sparks were bad it woulldnt end after cold start is over

[hugosf]

Thanks

Yeah, never had any problem during cold start.

I refer the term misfire , because it really looks and sounds /acts like a misfire , the engine idle struggles to keep stabilized, going up and down and very rough.

If i accelerate a bit the rpms , it stabilizes quicker

[hugosf]

Well ,

After installing new plugs , and at dealer they didnt find anything wrong.

But fact is that it continued doing this erratic cold start, with small misfiring and rpms going up n down.


Yesterday , after 7000k it got into limp/safe mode, with the message of all engine power not available.

Stopped the car, restart its all good unless i reach past 7000 , then will go safe mode again. I cant feel any difference if it doesnt go into safe mode after 7000.

Perhaps all this is because of the ICV ?

[S65V8]

Something similar happened to me recently and what I found is that intake was so dirty it affected that idle and pop up a ICV code. I cleaned it and hasn't happened since. Check the intake.

Originally Posted by hugosf

Well ,

After installing new plugs , and at dealer they didnt find anything wrong.

But fact is that it continued doing this erratic cold start, with small misfiring and rpms going up n down.


Yesterday , after 7000k it got into limp/safe mode, with the message of all engine power not available.

Stopped the car, restart its all good unless i reach past 7000 , then will go safe mode again. I cant feel any difference if it doesnt go into safe mode after 7000.

Perhaps all this is because of the ICV ?

[hugosf]

Hello,

When you refer dirty , is which part of he intake ?

Thanks hugo

[hugosf]

Well, after The messaged for The safe mode i got it conected to The computer to see The problem .

Error : 27E4

It has to do with The brake servo connections etc


Im fact, i ve been hearing a strange buzzing sound from The left side when im stopped...

Hope its a easy fix and turns out a simple defect hose

[hugosf]

Heres the part that was replaced, with the vaccum hoses.

Problem solved, no more engine problem

[happos2]

Thanks for following up with the solution. Surely this will help someone in the future.

Always seems that people post an issue, use our advice, and never post again to determine if the advice was worth it. You did just the opposite and this will prove helpful!

Cheer!