Instead of an air volume flow meter, an air mass flow meter is installed. The air mass meter has the following advantages: Automatic compensation for changes in temperature and altitude, no moving parts and therefore even less wear. Air mass measurement principle: An electrically heated heating coil is cooled by the air flowing through it. To maintain a constant temperature of the coil, the filament current changes in accordance with the density and temperature of the flowing air. By changing the heating current, the Motronic system determines the mass of the intake air and, in accordance with this, changes the amount of fuel injected.
The ignition system has no moving parts and is therefore not subject to wear apart from the spark plugs, see section "Ignition system". In addition, the ignition control system turns off the ignition system if it is defective (e.g. broken wires).
On automatic transmission models, the integration of DME and automatic control further improves transmission tuning and smooths shifting.
Attention: When working on the fuel injection device, it is necessary to observe impeccable cleanliness, see next section.