Digital Motor Electronics

Functional Diagram of DME M1.7 for M42:

The M42 is equipped with the latest digital motor electronics engine management system. Designated DME M1.7, the new system features optimized component technology, weight saving design and expanded adaptive self-learning functions.






The M1.7 DME system controls a new multi-coil, "motionless" ignition system. Each cylinder has a separate ignition coil which is controlled by individual DME control unit final stages. The ignition coils are of a new design using a new ground connection and are rated to 30KV.



A new spark plug developed by BMW is used to complete the new M1.7 engine management system. The new spark plug features a 14 mm thread, a three-arm "platform" electrode and requires no adjustment. The platform electrode provides a large conductive area which maintains a constant air gap and a uniform flame front during the spark plug's service life.


The new "motionless" BMW ignition system operates without moving parts thus secondary contact wear and tear is eliminated. Other advantages include a wider ignition timing adjustment range, elimination of secondary arcing and stray RFI with improved ignition coil performance during peak loads.



The crankshaft torsional vibration damper and the pulse wheel are combined. As with previous DME systems, the increment teeth signal engine RPM while the tooth gap represents the TDC reference point.