ENGINE AND EMISSION CONTROL PARTS DESCRIPTION

The E.C.U. consists of a microcomputer, inspection lamp, a diagnostic mode selector, and connectors for signal input and output and for power supply. The unit controls the engine by processing input data received from sensors about the vehicle. From information received about the vehicle's ambient conditions such as speed, coolant temperature, accelerator position etc., the processor determines the optimum running parameters and outputs current pulses to control the operation of the injector solenoids and hence the engine performance. The ECU is located behind the front console and is accessed by removing the LH and RH lower instrument panel covers.

The crank angle sensor is a basic component of the entire E.C.C.S. It monitors engine speed and piston position, and sends signals to the E.C.U. to control fuel injection, ignition timing and other functions. The crank angle sensor has a rotor plate with 5 slits. In the 1 channel time control system, the sensor detects the cylinder No. 1 piston's TDC position for cylinder identification, during the compression stroke. For this a narrow slit is provided on the rotor plate. Four long slits are provided on the rotor plate (one for each cylinder) to detect the crank angle. This is done by detecting the starting point of each slit when passing the optical sensor. The engine speed is determined by measuring the time the slit needs to pass the optical sensor.