System Outline

This system utilizes an Engine Control Module and maintains overall control of the engine. transmission and so on. An outline of the engine control is explained here.

1. INPUT SIGNALS
1. Engine Coolant Temp. Signal Circuit
The engine coolant temp. sensor detects the engine coolant temp. and has a built-in thermistor with a resistance which varies according to the engine coolant temp. the engine coolant temp. is input into TERMINAL THW of engine control module as a control signal.
2. Intake Air Temp. Signal Circuit
The intake air temp. sensor is installed in the mass air flow meter and detects the intake air temp., which is input as a control signal to TERMINAL THA of Engine Control Module.
3. Oxygen Sensor Signal Circuit
The oxygen density in the exhaust emission is detected and input as a control signal from the heated oxygen sensor (Bank 1 Sensor 1, Bank 2 Sensor 1, Bank 1 Sensor 2 and Bank 2 Sensor 2) to TERMINALS OXL1, OXR1, OXL2 and OXR2 of the Engine Control Module.
To stabilize detection performance by the heated oxygen sensor, the heated oxygen sensor is warmed. This heater is also controlled by the Engine Control Module (HTL1, HTR1, HTL2 and HTR2).
4. RPM Signal Circuit
Camshaft position is detected by the Camshaft Position Sensor 1 and 2 and its signal is input to TERMINALS G1+, G2+ of Engine Control Module as a control signal. Also, the engine RPM is detected by the Crankshaft Position Sensor installed in the cylinder block and the signal is input into TERMINAL NE of Engine Control Module as a control signal.
5. Throttle Signal Circuit
The Throttle Position Sensor detects the throttle valve opening angle as a control signal, which is input into TERMINAL VTA1 of the Engine Control Module. When the valve is completely closed, the control signal is input into TERMINAL IDL1.
6. Vehicle Speed Circuit
The vehicle speed is detected by Vehicle Speed Sensor installed in the transmission and the signal is input to TERMINAL SPDM of the Engine Control Module via the Comb. Meter.
7. Neutral Start Signal Circuit
The Park/Neutral position SW detects whether the shift position is in neutral or not, and the signal is input into TERMINAL NSW of the Engine Control Module.
8. A/C SW Signal Circuit
The operating voltage of the A/C Magnetic Clutch is detected and the signal is input into TERMINAL AC of Engine Control Module as a control signal.
9. Battery Signal Circuit
Voltage is constantly applied to TERMINAL BATT of the Engine Control Module. With the ignition SW turned ON, the voltage for Engine Control Module start-up power supply is applied to TERMINAL +B of Engine Control Module via EFI relay.
The current flowing through the IGN fuse flows to TERMINAL IGSW of the Engine Control Module.
10. Intake Air Volume Signal Circuit
Intake air volume is detected by the mass air flow meter and the signal is input to TERMINAL VG of the Engine Control Module as a control signal.
11. Stop Light SW Signal Circuit
The stop light SW is used to detect whether or not the vehicle is braking and the signal is input into TERMINAL BK of the Engine Control Module as a control signal.
12. STA Signal Circuit
To confirm whether the engine is cranking. the voltage applied to the starter motor during cranking is detected and the signal is input into TERMINAL STA of the Engine Control Module as a control signal.
13. Engine Knock Signal Circuit
Engine knocking is detected by Knock Sensor 1 and 2 and the signal is input into TERMINALS KNK1 and KNK2 as a control signal.

2. CONTROL SYSTEM
* Sequential Multiport Fuel Injection (Electronic Fuel Injection) System
The Sequential Multiport Fuel Injection (Electronic fuel injection) system monitors the engine condition through the signals input from each sensor (input signals from (1) to (13) etc.) to the Engine Control Module. The best fuel injection timing is decided based on this data and the program memorized by the Engine Control Module, and the control signal is output to TERMINALS #10, #20, #30, #40, #50, #60, #70 and #80 of the Engine Control Module to operate the Injector (inject the fuel). The sequential multiport fuel injection (electronic fuel injection) system produces controls of fuel injection operation by the Engine Control Module in response to the driving conditions.

* ESA Electronic Spark Advance) System
The ESA system monitors the engine condition through the signals input to the Engine Control Module from each sensor (input signals from (1), (2), (4) to (13) etc.). The best ignition timing is decided according to this data and the memorized data in the Engine Control Module, and the control signal is output to TERMINAL IGT1 and IGT2. This signal controls the Igniter to provide the best ignition timing for the driving conditions.

* Fuel Pressure Control System
The fuel pressure control system causes the VSV for fuel pressure control) to come on for high temp. Starting and increases the fuel pressure to improve startability at high temperatures and to provide stable idling. The Engine Control Module evaluates the input signals from each sensor ((1), (2), (4), (9) and (10) etc.), and outputs current to TERMINAL PR of Engine Control Module to control the VSV.

* Heated Oxygen Sensor Heater Control System
The Heated Oxygen Sensor Heater Control System turns the heater ON when the intake air volume is low (temp. of exhaust emissions is low), and warms up the heated oxygen sensor (Bank 1 Sensor 1, Bank 2 Sensor 1, Bank 1 Sensor 2, Bank 2 Sensor 2) to improve detection performance of the sensor.

The Engine Control Module evaluates the signals from each sensor input signals from (1), (2), (4), (9) to (11) etc.), and outputs current to TERMINALS HTL1, HTR1, HTL2 and HTR2 to control the heater.

* Idle Air Control (Idle Speed Control) System
The idle air control system (step motor type) increases the RPM and provides idling stability for fast idle-up when the engine is cold, and when the idle speed has dropped due to electrical load and so on. The Engine Control Module evaluates the signals from each sensor (input signals from (1), (4), (5), (8), (9), (11) etc.), outputs current to TERMINAL ISC1, ISC2, ISC3 and ISC4 to control idle air control valve.

* EGR Control System
The EGR Control System detects the signal from each sensor (input signals from (1), (4), (9), (10) etc.), and outputs current to TERMINAL EGR1, EGR2, EGR3, EGR4 to control the EGR valve.

3. DIAGNOSIS SYSTEM
With the diagnosis system, when there is a malfunction in the Engine Control Module Signal System, the malfunctioning system is recorded in the memory. The malfunctioning system can be found by reading the code displayed by the malfunction indicator lamp.

4. FAIL-SAFE SYSTEM
When a malfunction has occurred in any system, if there is a possibility of engine trouble being caused by continued control based on the signals from that system, the fail-safe system either controls the system by using data (standard values) recorded in the Engine Control Module memory or else stops the engine.