Cold Start, RPM Moves Up and Down Violently

[steve9733]

Any bros have this issue below ? Pls help as there is no fault code detected
in the diagnostics.. Driving 2012 BMW 520i...

In the morning when cold start, the RPM will move up and down quite violently
until it settles down after 1 plus minutes.. It will be normal after the engine is
warm up and running.. This does not happen last time before.. The RPM will
just move high, then settles down after 15 seconds and tat is it..

I had changed sparks plugs, ignition coil, new battery, thermostat..

Is there anything I had missed changing to rectify this problem ?

Thanks in advance for all helping to contribute... Thanks..

 

[Ah yang]

Re: Cold Start, RPM Moves Up and Down Violently

Try reset ur engine adaption. Happen to my f30 320 also. Mine even engine also stall. Fren intro me to a ws at ubi. Solve it juz by resetting.

 

[steve9733]

Re: Cold Start, RPM Moves Up and Down Violently

Thanks Ah Yang, will try..

 

[steve9733]

Re: Cold Start, RPM Moves Up and Down Violently

For info changed pressure converter, which is having some weird readings..

Hopefully this is the main causes.. Really thanks to Codewerx for your professionalism
and solving the problem.. I only trust them so far.. Thanks..

 

[horrible]

Re: Cold Start, RPM Moves Up and Down Violently

What's a pressure converter?

 

[steve9733]

Re: Cold Start, RPM Moves Up and Down Violently

My problem really solved now, thanks to codewerx.. The pressure converter is a rectangular
item situated near the ignition coil, when you open up the engine cover..