BMW E65 N62 misfires on cold start
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E65 runs poorly when cold and gives misfire codes - what is the most common cause?
On the N62 engine, a typical cause is worn Valvetronic intermediate levers and eccentric shaft. Cylinder filling then becomes uneven, and the symptom shows especially on a cold start. There is also a service bulletin on the subject.
What does a worn Valvetronic need to be repaired?
The intake manifold is taken apart, and the shafts and intermediate levers need to be replaced. Because the wear affects all of them, it is worth renewing the intermediate levers and shafts on both sides. Replacing the spark plugs or vacuum diaphragms alone did not fix the fault.
What else can be behind the E65 stuttering when cold?
A leaking valve cover gasket can cause a misfire message, and repairing it is worth doing first. A stuck VANOS solenoid can also cause misfires in several cylinders; the fault has been fixed by replacing the solenoid.
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