Fuel Injectors

Each group of fuel injectors (No. 1 and 3, No. 2 and 4) is activated by DME/Motronic control unit final stage (current amplifier), making it possible to divide injection cycle into groups of cylinders. This allows limited engine operation even when one group fails. Injectors operate under parallel or semi-sequential fuel injection modes.

With parallel injection, simultaneous activation of ALL fuel injectors occurs for each crankshaft revolution, and takes place only when the camshaft sensor has not sent output signals since starting the engine. If camshaft sensor signal is sent out later, the system switches over to semi-sequential fuel injection as soon as an engine speed of 2500 RPM is exceeded.

Under semi-sequential fuel injection, only one group of cylinders operates once every 720 crankshaft degrees from an engine speed of 600 RPM. Semi-sequential fuel injection timing can function only when the DME/Motronic control unit receives a signal from the camshaft sensor.