Nissan Pulsa Electronic Control Units (ECUs) provide precise control of fuel and ignition. The ECU consists of a miroprocessor, inspection lamps and a diagnostic mode selector for signal input and output, and for power supply. The unit has control of the following functions: injected fuel amount, mixture ratio feedback, ignition timing, idle speed, EGR operation, AIV operation, fuel pump operation, air regulator operation, power valve control, acceleration cut control, and self-diagnostic system. The following schematic illustrates the Nissan Pulsar Electronic Control Unit Wiring Diagram (1989 model) ~ Click image to enlarge.
The ECU calculates the basic injection pulse width by processing signals from the crank angle sensor and air flow meter. Receiving signals from each sensor which detects various engine conditions, the ECU adds various enrichments, which are pre-programmed in the ECU, to the basic injections amount. Thus, the optimum amount of fuel is injected through the injectors.