GENERAL INFORMATION

The Multipoint Fuel Injection System consists of sensors which detect the engine conditions, the engine-ECU <M/T> or engine-A/T-ECU <A/T> which controls the system based on signals from these sensors, and actuators which operate under the control of the engine-ECU <M/T> or engine-A/T-ECU <A/T>. The engine-ECU <M/T> or engine-A/T-ECU <A/T> carries out activities such as fuel injection control, idle speed control and ignition timing control. In addition, the engine-ECU <M/T> or engine-A/T-ECU <A/T> is equipped with several diagnosis modes which simplify troubleshooting when a problem develops.

FUEL INJECTION CONTROL <VEHICLES WITH CATALYTIC CONVERTER>

The injector drive times and injector timing are controlled so that the optimum air/fuel mixture is supplied to the engine to correspond to the continually-changing engine operation conditions.
A single injector is mounted at the intake port of each cylinder. Fuel is sent under pressure from the fuel tank by the fuel pump, with the pressure being regulated by the fuel pressure regulator. The fuel thus regulated is distributed to each of the injectors.
Fuel injection is normally carried out once for each cylinder for every two rotations of the crankshaft. The firing order is 1-2-3-4-5-6. This is called sequential fuel injection. The engine-ECU <M/T> or engine-A/T-ECU <A/T> provides a richer air/fuel mixture by carrying out "open-loop" control when the engine is cold or operating under high load conditions in order to maintain engine performance. In addition, when the engine is warm or operating under normal conditions, the engine-ECU <M/T> or engine-A/T-ECU <A/T> controls the air/fuel mixture by using the oxygen sensor signal to carry out "closed-loop" control in order to obtain the theoretical air/fuel mixture ratio that provides the maximum cleaning performance from the three way catalyst.

FUEL INJECTION CONTROL <VEHICLES WITHOUT CATALYTIC CONVERTER>

The injector drive times and injection timing are controlled so that the optimum air/fuel mixture is supplied to the engine to correspond to the continually-changing engine operation conditions. A single injector is mounted at the intake port of each cylinder. Fuel is sent under pressure from the fuel tank by the fuel pump, with the pressure being regulated by the fuel pressure regulator. The fuel thus regulated is distributed to each of the injectors. Fuel injection is normally carried out once for each cylinder for every two rotations of the crankshaft. The firing order is 1-2-3-4-5-6. This is called sequential fuel injection. The engine-ECU <M/T> or engine-A/T-ECU <A/T> provides a richer air/fuel mixture by carrying out "open-loop" control when the engine is cold or operating under high load conditions in order to maintain engine performance.

THROTTLE VALVE OPENING CONTROL

This system electrically controls the opening of the throttle valve. The engine-ECU <M/T> or engine-A/T-ECU <A/T> detects the amount of travel of the accelerator pedal via the accelerator pedal position sensor, and controls the actuation of the throttle actuator control motor, which is mounted on the throttle body, in order to attain the target throttle valve opening that has been predetermined in accordance with driving conditions.

IGNITION TIMING CONTROL

The power transistor located in the ignition primary circuit turns ON and OFF to control the primary current flow to the ignition coil. This controls the ignition timing in order to provide the optimum ignition timing with respect to the engine operating conditions. The ignition timing is determined by the engine-ECU <M/T> or engine-A/T-ECU <A/T> from the engine speed, intake air volume, engine coolant temperature and atmospheric pressure.

SELF-DIAGNOSIS FUNCTION

When an abnormality is detected in one of the sensors or actuators related to emission control, the engine warning lamp (check engine lamp) illuminates as a warning to the driver.
When an abnormality is detected in one of the sensors or actuators, a diagnosis code corresponding to the abnormality is output.
The RAM data inside the engine-ECU <M/T> or engine-A/T-ECU <A/T> that is related to the sensors and actuators can be read by means of the M.U.T.-III. In addition, the actuators can be force-driven under certain circumstances.

OTHER CONTROL FUNCTIONS

Fuel Pump Control
Turns the fuel pump relay ON so that current is supplied to the fuel pump while the engine is cranking or running.
A/C Relay Control
Turns the compressor clutch of the A/C ON and OFF.
Alternator Output Current Control
Prevents alternator output current from increasing suddenly and idle speed from dropping at times such as when the headlamp is turned on.
Purge Control Solenoid Valve Control <vehicles with catalytic converter>
[Refer to GROUP 17 - Emission Control - Evaporative Emission Control System].
Exhaust Gas Recirculation Control Solenoid Valve Control [Refer to GROUP 17 - Emission Control - Exhaust Gas Recirculation System ].

GENERAL SPECIFICATIONS

Items		Specifications
Throttle body	Throttle bore mm	65
	Throttle position sensor	Variable resistor type
	Throttle valve control servo	DC motor type, having broshes
Engine-ECU <M/T>	Identification No.	E6T49775 <Vehicles for General Export with catalytic converter> E6T49777<Vehicles for General Export without catalytic converter> E6T49776 <Vehicles for GCC>
Engine-A/T-ECU <A/T>	Identification No.	E6T49783 <Vehicles for General Export with catalytic converter> E6T49785<Vehicles for General Export without catalytic converter> E6T49784 <Vehicles for GCC>
Sensors	Air flow sensor	Heat sensitizing
	Barometric pressure sensor	Semiconductor type
	Intake air temperature sensor	Thermistor type
	Engine coolant temperature sensor	Thermistor type
	Oxygen sensor <vehicles with catalytic converter>	Zirconia type
	Vehicle speed sensor	Magnetic resistance element type
	Accelerator pedal position sensor	Hall element type
	Camshaft position sensor	Hall element type
	Crank angle sensor	Hall element type
	Power steering fluid pressure switch	Contact switch type
	Manifold absolute pressure sensor	Semiconductor type
	Mixture adjusting screw (variable resistor) <vehicles without catalytic converter>	Variable resistor type
Actuators	Engine control relay type	Contact switch type
	Fuel pump relay type	Contact switch type
	Injector type and number	Electromagnetic type, 6
	Injector identification mark	JLN240B
	Exhaust gas recirculation valve	Duty cycle type solenoid valve
	Purge control solenoid valve	Duty cycle type solenoid valve
	Throttle valve control servo relay	Contact switch type
Fuel pressure regulator	Regulator pressure kPa	324

MULT-POINT FUEL INJECTION SYSTEM DIAGRAM

<Vehicles without catalytic converter>

<Vehicles with catalytic converter>