Terminology

Engine Temperature Sensor	The engine temperature sensor, located on the top of water inlet housing, detects engine coolant temperature and transmits a Signal to the E.C.U. The temperature sensing unit employs a thermistor which is sensitive to the change in temperature. Electrical resistance of the thermistor decreases in response to the temperature rise.
Throttle Sensor & Soft/Hard Idle Switch	The throttle sensor responds to accelerator pedal movement. This sensor is a kind of potentiometer which transforms the throttle valve position into output voltage, and emits the voltage signal to the E.C.U. In addition, the sensor detects the opening and closing speed of the throttle valve and feeds the voltage Signal to the E.C.U. Idle position of the throttle valve is determined by the E.C.U. receiving the signal from the throttle sensor. This system is called ''soft idle switch''. It controls engine operation such as fuel cut. On the other hand, ''hard idle switch'', which is built in the throttle sensor unit, is used for engine control) when soft idle switch is malfunctioning.
E.C.C.S. Control Unit (E.C.U.)	The E.C.U. consists of a microcomputer, an inspection lamp, a diagnostic mode selector, and connectors for signal input and output and for power supply. The unit controls the engine.
Crank Angle Sensor	The crank angle sensor is a basic component of the 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 and a wave-forming circuit. The rotor plate has 360 slits for 1⁰ signal and 6 slits for 120⁰signal. Light Emitting Diodes (L.E.D.) and photo diodes are built in the wave-forming circuit. When the rotor plate passes between the L.E.D. and the photo diode, the slits in the rotor plate continually cut the light being transmitted to the photo diode from the L.E.D. This generates rough-shaped pulses which are converted into on-off pulses by the wave-forming circuit, which are sent to the E.C.U.
Air Flow Meter	The air flow meter measures the intake air flow rate by measuring a part of the entire flow. Measurements are made in such a way that the E.C.U. receives electrical output signals varied by the amount of heat emitting from the hot film placed in the stream of the intake air. When intake air flows into the intake manifold through a route around the hot film, the heat generated from the hot film is taken away by the air. The amount of heat reduction depends on the air flow. The temperature of the hot film is automatically controlled to a certain number of degrees. Therefore, it is necessary to supply the hot film with more electric current (n order to maintain the temperature of the hot film. The E.C.U. detects the air flow by means of this current change.
Pressure Regulator	The pressure regulator maintains the fuel pressure at 299.1 k (2.991 bar, 3.05 kg/cm³, 43.4 psi). Since the injected fuel amount depends on injection pulse duration, it is necessary to maintain he pressure at the above value.
Fuel lnjector	The fuel injector is a small, elaborate solenoid valve. As the E.C.U. sends injection signals to the injector, the coil in the injector pulls the needle valve back and fuel is released into the intake manifold through the nozzle. The injected fuel is controlled by the E.C.U. in terms of injection pulse duration.
Exhaust Gas Sensor (Lambda or O₂ Sensor)	The exhaust gas sensor, which is placed into the exhaust outlet, monitors the amount of oxygen in the exhaust gas. The sensor has a closed-end tube made of ceramic zirconia. The outer surface of the tube is exposed to exhaust gas, and the inner surface to atmosphere. The zirconia of the tube compares the oxygen density of exhaust gas with that of atmosphere, and generates electricity. In order to improve generating power of the zirconia, its tube is coated with platinum. The voltage is approximately 1V in a richer condition of the mixture ratio than the ideal air-fuel ratio, while approximately 0V in leaner conditions. The radical change from 1V to 0V occurs at around the ideal mixture ratio. In this way, the exhaust gas sensor detects the amount of oxygen in the exhaust gas and sends the signal of approximately 1V or 0V to the E.C.U. A heater is used to activate the sensor.
Fuel Pump	The fuel pump is an in tank type with a fuel damper. Both the pump and damper are located in the fuel tank.
Fuel Damper	The fuel damper, which consists of a diagram, reduces fuel pressure pulsation in the fuel feed in between the fuel filter and injectors.
Power Transistor Unit & Ignition Coil	The ignition signal from the E.C.U. is amplified by the power transistor, which turns the ignition coil primary circuit on and off, inducing the proper high voltage in the secondary circuit. The ignition coil is a small, moulded type.
Air Regulator	The air regulator provides an air bypass when the engine is cold for a fast idle during warm-up. A bimetal, heater and rotary shutter are built into the air regulator. When the bi-metal temperature is Low, the air bypass port opens. As the engine starts and electric current flows through a heater, the bimetal begins to turn the shutter to close the bypass port. The air passage remains closed until the engine stops and the bi-metal temperature drops.
Idle Air Adjusting (I.A.A.) Unit	The I.A.A. unit is made up of the A.A.C. valve, F.l.C.D. solenoid valve and idle adjust screw. It receives the signal from the E.C.U. and controls the idle speed at the preset value. The F.I.C.D. solenoid valve compensates for changes in idle speed caused by the operation of the air compressor.
Auxiliary Air Control (A.A.C.) Valve	The E.C.U. actuates the A.A.C. valve by an ON/OFF pulse. The longer that ON duty is left on, the larger the amount of air that will flow through the A.A.C. valve.
Power Steering Oil Pressure Switch	The power steering oil pressure switch is attached to the power steering high-pressure tube and detects the power steering load, sending the load signal to the E.C.U. The E.C.U. then sends the idIe-up signal to the A.A.C. valve.
Vehicle Speed Sensor	The vehicle speed sensor provides a vehicle speed signal to the E.C.U. The speed sensor consists of a reed switch, which is installed in the speedometer unit and transforms vehicle speed into a pulse Signal.
Detonation Sensor	The detonation sensor is attached to the cylinder block and senses engine knocking conditions. A knocking vibration from the cylinder block is applied as pressure to the piezoelectric element. This vibration is then converted into a voltage signal which is sent to the E.C.U.
E.G.R. Control Valve	The E.G.R. control valve controls the quantity of exhaust gas to be diverted to the intake manifold through vertical movement of a taper valve connected to the diaphragm. Vacuum is applied to the diaphragm in response to the opening of the throttle valve.
E.G.R. Control Solenoid Valve	The solenoid valve responds to the ON/OFF signal from the E.C.U. When it is off, a vacuum signal from the throttle chamber is fed into the E.G.R. control valve. When the control unit sends an ON signal, the coil pulls the plunger downward and cuts the vacuum signal.
Pressure Regulator Vacuum Relief (P.R.V.R.) Control Solenoid Valve	The solenoid valve responds to the ON/OFF signal from the E.C.U. When it is ON, a vacuum signal from the intake manifold is fed into the pressure regulator. When the control unit sends an ON signal, the coil pulls the plunger downward and cuts the vacuum signal.
A.I.V. Control Solenoid Valve	The solenoid valve responds to the ON/OFF signal from the E.C.U. When it is ON, a vacuum signal from the intake manifold is fed into the A.I.V. control valve. When the control unit sends an OFF signal, the coil pulls the plunger downward and cuts the vacuum signal.
Waste gate Valve Control Solenoid Valve	The solenoid valve responds to the ON/OFF signal from the E.C.U. When it is ON, a vacuum signal from the suction pipe or compressor outlet is fed into the waste gate valve actuator. The actuator is hard to open at this time. When the control unit sends an OFF signal, the coil pulls the plunger upward and cuts the route to the suction pipe.
Fuel Filter	The specially designed fuel filter has a metal case in order to withstand high fuel pressure.
Diagnostic Connector for CONSULT	The diagnostic connector for CONSULT is located above the hood release handle.
Air lnduction Valve (A.I.V.)	The air induction valve sends secondary air to the exhaust manifold, using a vacuum created by exhaust pulsation in the exhaust manifold. When the exhaust pressure is below atmospheric pressure (negative pressure), secondary air is sent to the exhaust manifold. When the exhaust pressure is above atmospheric pressure, the reed valves prevent secondary air from being sent back to the sub-air cleaner.
Valve Timing Control (V.T.C.) Solenoid Valve	The valve timing control solenoids are installed at the rear end of the intake camshafts, and control oil pressure which regulates the position of the intake camshafts.
Carbon Canister	The carbon canister is filled with active charcoal to absorb evaporative gases produced in the fuel tank. These absorbed gases are then delivered to the intake manifold by manifold vacuum for combustion purposes.
Fuel Temperature Sensor	The fuel temperature sensor, built into the fuel tube, senses fuel temperature. When the fuel temperature is higher than specified, the E.C.C.S. control unit turns the P.R.V.H. control solenoid valve ON and raises fuel pressure.