The unit has a memory for the basic injection duration at different engine speeds and manifold pressures. The basic duration, being read from the memory, is then changed by signals sent from various sensors to obtain the final injection duration.
Other features include:
Engine Start Control - The fuel mixture must be changed according to different operating modes. For example, at the moment of starting, the mixture must be enriched. Therefore, the injection duration read from the computer memory is specified by signals about the position of the starter, engine speed, coolant temperature, which ensures the supply of additional fuel at the moment of starting the engine.
Injector Control - The ECU controls the injection duration at different engine speeds and loads.
Electronic Air Control The ECU controls the EACV to provide the idle speed required by the engine and accessories.
Ignition Control - The ECU controls the ignition timing selection based on engine load and speed, vehicle speed and coolant temperature.
Fuel Pump Control - When the engine is not running but the ignition is on, the fuel pump is turned off to prevent fuel injection.
Fuel Cut-off Control - During braking, with the throttle valve almost completely closed, and when the engine speed is about 1300-1500 rpm, the power supply to the injectors is interrupted, which increases the efficiency of the engine. The fuel cut-off function also operates when the engine speed exceeds the maximum safe value (red line).
Fail-safe - If the ECU detects a sensor signal that is lost or out of range, the computer ignores the faulty signal and uses a "fixed value" instead. This value is not necessarily correct for the immediate situation, but it will allow the engine to operate. For example, many ECU decisions are based on coolant temperature. If the coolant temperature sensor (TW sensor) signal is lost immediately after a cold start, the ECU will use a "default" temperature value. This default value is based on normal engine temperature, and therefore the car will operate until it overheats.
Backup System - The ECU also checks itself during operation. If deviations occur within the ECU, the system will switch to backup circuits independent of the processor system. The backup system outputs fixed values for all inputs and controls the injector accordingly. The vehicle's capabilities are reduced to minimum performance.
Self-diagnosis - When something abnormal happens, the ECU turns on the hazard warning lamp and stores the fault code in the erasable (reprogrammable) memory. The ECU LEDs always display the fault code when the ignition is turned on.
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