Fuel injection system — description

1.8 models are equipped with Bosch L3 Jetronic fuel injection system, 2.0 models are equipped with Bosch Motronic ML4 engine management system. Both systems function in much the same way, although the Motronic system also includes such elements as an idle speed control unit, a control unit that is completely integrated into the ignition system, and the diagnostic system itself. The latter system reports any damage through coded signals displayed when activated.

The main components of the system:

• a) A control unit that determines the duration of injection according to information received from various sensors on the engine.
• b) Fuel injectors, for supplying the cylinders with an appropriate portion of fuel.
• c) Air flow sensor, to measure the volume of air entering the engine.
• d) Electrically controlled fuel pump.
• e) The fuel pump control relay, which includes double contacts, one of which is controlled by an ignition pulse. This ensures that the fuel pump is turned off if the engine is not running.

In addition, the essential elements of the system are the fuel filter, throttle switch, fuel pressure regulator, coolant temperature sensor, auxiliary pneumatic valve (L3 system only), idle speed controller (only Motronic system) and intake air temperature sensor (only Motronic system).