DME System: Description
The Porsche 944 is equipped with the Bosch DME digital electronic engine control system. The DME system uses various data sensors that monitor intake air volume, speed, crankshaft position, coolant temperature, intake air temperature, and throttle position.
Signals from these sensors, as well as a start signal and oxygen sensor signal, are sent to the electronic control unit.
The electronic control unit (ECU) is a microcomputer, and is the "brain" of the DME system. Using information obtained from data sensors, the ECU determines the correct amount of fuel and optimum ignition timing.
The DME control unit switches from open loop to closed loop operation when the coolant temperature is above 113°F (45°C), and when the oxygen sensor temperature is above 480°F (250°C).