System Outline

This system utilizes an Engine Control Module (ECM) (engine ECU for M/T; engine and electronically controlled transmission ECU for A/T) and maintains overall control of the engine, transmission and so on. An outline of the engine control is explained here.

INPUT SIGNALS
1. Engine Coolant Temp. (Water Temp.) Signal System
The engine coolant temp. sensor (EFI Water Temp. Sensor) detects the engine coolant temp. and has a built-in Thermistor with a resistance which varies according to the engine coolant temp. (water temp.) Thus the engine coolant temp. is input in the form of a control signal into TERMINAL THW of the ECM

2. Intake Air Temp. Signal System
The Intake Air Temp. Sensor detects the intake air temp., which is input as a control signal into TERMINAL THA of the ECM

3. Oxygen Sensor Signal System
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINAL OX1 and OX2 of the ECM

4. RPM Signal System
Crankshaft position and engine RPM are detected by the pick-up coil installed inside the distributor. Crankshaft position is input as a control signal into TERMINALS NE, of the ECM, and rpm is input into TERMINAL G+.

5. Throttle Signal System
The Throttle Position Sensor detects the throttle valve opening angle, which is input as a control signal into TERMINAL VTA of the ECM.

6. Vehicle Speed Signal System
The Vehicle Speed Sensor (Speed Sensor), installed inside the transmission, detects the vehicle speed and inputs a control signal into TERMINAL SPD of the ECM

7. Park/Neutral Position SW (Neutral Start SW) Signal System (A/T))
The Park/Neutral Position SW (Neutral Start SW) detects whether the shift position are in neutral, parking or not, and inputs a control signal into TERMINAL NSW of the ECM

8. A/C SW Signal System
The A/C Amplifier inputs the A/C operations into TERMINAL AC1 of the ECM as a control signal.

9. Battery Signal Circuit
Voltage is constantly applied to TERMINAL BATT of the ECM. When the Ignition SW is turned ON, the voltage for ECM start-up power supply is applied to TERMINALS +B of ECM via EFI main relay.

10. Intake Air Volume Signal System
Intake air volume is detected by the manifold absolute pressure sensor (Vacuum Sensor) (for manifold pressure) and is input as a control signal into TERMINAL PIM of the ECM

11. 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 ECM as a control signal.

12. Engine Knock Signal Circuit
Engine knocking is detected by knock sensor and the signal is input into TERMINAL KNK as a control signal.

13. Electrical Load Signal System
The signal when systems such as the Rear Window Defogger, Headlights, etc. which cause a high electrical burden are ON is input to TERMINAL ELS as a control signal.

CONTROL SYSTEM
^ SFI (Sequential Multiport Fuel Injection) System
The SFI (EFI) system monitors the engine condition through the signals, which are input from each Sensor (input signals from 1 to 13, etc.) to the ECM. The best fuel injection volume is decided based on this data and the program memorized by the ECM, and the control signal is output to TERMINALS #10, #20, #30 and #40 of the ECM to operate the Injector. (Inject the fuel). The SFI (EFI) system produces control of fuel injection operation by the ECM in response to the driving conditions.

^ ESA (Electronic Spark Advance) System
The ESA system monitors the engine condition through the signals, which are input to the ECM from each Sensor (input signals from (1, 2, 4 to 12, etc.) the best ignition timing is detected according to this data and the memorized data in the ECM, and the control signal is output to TERMINAL IGT. This signal controls the Igniter to provide the best ignition timing for the driving conditions.

^ IAC (Idle Air Control (ISC)) System
The IAC (ISC) system (rotary solenoid 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, etc. The ECM evaluates the signals from each sensor (input signals 1, 4 to 8, 13, etc.), outputs current to TERMINALS RSO and RSC, and controls the Idle Air Control Valve (ISC Valve).

^ Fuel Pump Control System
The ECM operation outputs to TERMINAL FC and controls the circuit opening relay. Thus controls the fuel pump drive speed in response to conditions.

^ EGR Control System
The EGR cut control system controls the VSV (for EGR) by evaluating the signals from each sensor which are input to the ECM (input signals (1, 5, 6, 9, etc.) and by sending output to TERMINAL EGR of the ECM.

^ A/C Cut Control System
When the vehicle suddenly accelerates from low engine speed, this system cuts off air conditioning operation for a fixed period of time in response to the vehicle speed and throttle valve opening angle in order to maintain acceleration performance.
The ECM receives input signals (5, 6, etc), and outputs signals to TERMINAL ACT

^ Diagnosis System
With the diagnosis system, when there is a malfunctioning in the ECM signal system, the malfunction system is recorded in the memory. The malfunctioning system can then be found by reading the display (code) of the malfunction indicator lamp (check engine warning light).

^ Fail-Safe System
When a malfunction occurs 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 ECM memory or else stops the engine.