12-02-2012, 05:51 AM
Location: UK Liverpool
Join Date: Jan 2010
Mein Auto: BMW 645 2005
I know this may be dismissed but this is a 99% certainty here, maybe more, and i'm afraid its not good news at all
On these engines the intermediate levers for the valvetronic system are prone to wearing out
This means that you won't get the full travel of the levers which in turn affects the valve lift and therefore running of the engine. It seems to cause more issues at idle from stone cold than anything else.
Any cars with an issue or starting to have an issue will run very poor from a cold start and more often than not throw a management light. Code reading will show up multiple misfires on each cylinder as has happened with yourself.
Usually with cars that are just starting to exhibit these symptoms, after about 30 seconds or so, the idle will smooth out and the car will run fine for the remainder of the day and at subsequent starts. Cars that are experiencing more severe wear of the levers may very well not get better to the point you don't notice misfires or poor running.
A lot of the time the problem can be masked by simply unplugging one of the vanos solenoids which renders the vanos and valvetronic in a static state. You won't see or feel any of the symptoms and the code thrown will be stored although not flagged up as a management light. However the downside to this, although it is certainly the lesser of 2 evils is you will more than likely notice lack of power through disabled vanos.
The levers were changed by BMW to a different type from about late 2005 or so (build date), and the whole debacle is coverd under service bulletin SI B 11 02 05. In North America they would do something about it but not here in Europe (as per usual).
Its a very big job to correct and you need a special jig for the cylinder heads so its not really a DIY.
Rather than have you spend oodles of cash on the problem replacing myriads of coil packs, plugs, vanos solenoids etc it may be better to go into a dealership forearmed and with a copy of the service bulletin to have them test in the same way it describes for a proper diagnosis.
I have the same issue on my 645i and i first noticed it as a frien and myself saw one of the solenoid plug wires to a vanos solenoid looked broken or even cut. We found out by reading the codes with INPA and decided we had found an issue and would repair the wiring. Upon repair the car ran fine until the next morning whereupon i experienced many of the symptoms you described.
After extensive misdiagnosis by a main dealer much to my repeated explanations to them and chargrin i found the issue myself through investigation on the internet.
It seems my plug was cut on purpose in order to mask the issue prior to my purchase of the car.
If you do want to pursue a repair may i recommend Steve at Mr Vanos over here in the UK. Whilst not the most insignificant amount of money ever spent it is certainly the cheapest option to remedy the car PROPERLY and he is well versed with the valvetronic system, has carried out the procedure before, and has all of the special tools required.
I hope this is of some help.