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


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 1-3-4-2. 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.

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 valve control servo 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.

IDLE SPEED CONTROL


The idle speed is kept at the optimum speed by controlling the amount of air that passes through the throttle valve in accordance with changes in idling conditions and engine load during idling.
The engine-ECU <M/T> or engine-A/T-ECU <A/T> drives the throttle valve control servo to keep the engine running at the pre-set idle target speed in accordance with the engine coolant temperature and A/C and other electrical load. In addition, when the air conditioning switch is turned off and on while the engine is idling, the throttle valve control servo adjusts the throttle valve passes through air amount according to the engine load conditions to avoid fluctuations in the engine speed.

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



OTHER CONTROL FUNCTIONS



  1. 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.
  2. A/C Relay Control
    Turns the compressor clutch of the A/C ON and OFF.
  3. Oil Control Valve Control
    The engine-ECU <M/T> or engine-A/T-ECU <A/T> effects duty cycle control on the engine oil control valve, in accordance with the engine speed. This regulates the supply of engine oil to the intake rocker shaft, which switches the cams.
  4. Fan Motor Control
    The revolutions of the radiator fan and condenser fan are controlled in response to the engine coolant temperature and vehicle speed.
  5. Alternator Output Current Control
    Prevents alternator output current from increasing suddenly and idle speed from dropping at times such as when the headlamp are turned on.
  6. Purge Control Solenoid Valve Control
    (Refer to , GROUP 17 - Engine And Emission Control - Evaporative Emission Control System).
  7. EGR Control Solenoid Valve Control
    [Refer to , GROUP 17 - Engine And Emission Control - Exhaust Gas Recirculation (EGR) System].

GENERAL SPECIFICATIONS


Items
 Specifications
Throttle body
 Throttle bore mm
 60
Throttle position sensor
 Hall element type
Throttle valve control servo
 DC motor type, having brush
Engine-ECU <M/T>
 Identification No.
 E6T41878 <General Export>
E6T41880 <GCC>
Engine-A/T-ECU <A/T>
 Identification No.
 E6T41877 <General Export>
E6T41881 <GCC, Australia and New Zealand>
Sensors
 Air flow sensor
 Heat sensitizing type
Barometric pressure Sensor
 Semiconductor type
Intake air temperature sensor
 Thermistor type
Engine coolant temperature sensor
 Thermistor type
Oxygen sensor
 Zirconia type
Accelerator pedal position sensor
 Hall element type
Vehicle speed sensor <M/T>
 Magnetic resistive element type
Inhibitor switch <A/T>
 Contact switch type
Camshaft position sensor
 Magneto resistance element type
Crank angle sensor
 Magneto resistance element type
Detonation sensor
 Piezoelectric type
Power steering fluid pressure sensor
 Semiconductor type
Actuators
 Engine control relay type
 Contact switch type
Fuel pump relay type
 Contact switch type
Injector type and number
 Electromagnetic type, 4
Injector identification mark
 HDA305E
Throttle valve control relay
 Contact switch type
Oil control valve
 Duty cycle type solenoid valve
EGR valve
 Stepper motor
Purge control solenoid valve
Duty cycle type solenoid valve
Fuel pressure regulator
 Regulator pressure kPa
 328

MULTI-POINT FUEL INJECTION SYSTEM DIAGRAM