System Outline
This system utilizes an ECM and maintains overall control of the engine, transaxle and so on. An outline of the engine control system is explained here.
- Input Signals
- Water temp. signal circuit
The E.F.I. engine coolant temperature sensor detects the engine coolant temperature and has a built-in thermistor whose resistance varies according to the engine coolant temperature. Thus the engine coolant temperature is input in the form of a control signal into TERMINAL THW of the ECM.
- Inlet air temp. signal circuit
The inlet air temp. sensor is installed in the intake air flow meter sub-assembly and detects the inlet air temperature, which is input as a control signal into TERMINAL THA of the ECM.
- Oxygen sensor signal circuit
The oxygen density in the exhaust emissions is detected by the oxygen sensors and input as a control signal to TERMINAL OX1B of the ECM.
- RPM signal circuit
The engine RPM is detected by the crank position sensor installed in the cylinder block and the signal is input into TERMINAL NE+ of the ECM as a control signal.
- Throttle signal circuit
The throttle with motor body assembly detects the throttle valve opening angle, which is input as a control signal into TERMINAL VTA1 of the ECM.
- Vehicle speed signal circuit
The speed sensor, detects the vehicle speed and inputs a control signal to TERMINAL SPD of the ECM.
- Battery signal circuit
Voltage is constantly applied to TERMINAL BATT of the ECM. When the ignition or starter switch assembly is turned on, the voltage for ECM start-up power supply is applied to TERMINALS +B and +B2 of the ECM via the EFI NO. 1 fuse. The current flowing through the IGN fuse flows to TERMINAL IGSW of the ECM.
- Started signal circuit
To confirm whether the engine is cranking, the voltage which is being applied to the starter motor during cranking is detected and the signal is input into TERMINAL STA of the ECM as a control signal.
- Water temp. signal circuit
- Control System
* Sequential multiport fuel injection system
The sequential multiport fuel injection system monitors the engine condition through the signals which are received from various sensors by the ECM. The best fuel injection volume is determined based on this data and the program stored in the ECM, and then control signals are output from TERMINALS #10, #20, #30 and #40 of the ECM to operate the fuel injectors (Inject the fuel). The sequential multiport fuel injection system controls the fuel injection operation via the ECM in response to the driving conditions.
* ESA system
The ESA system monitors the engine condition through the signals which are received from various sensors by the ECM. The best ignition timing is determined according to this data and the data stored in the ECM, and then control signals are output to TERMINALS IGT1, IGT2, IGT3 and IGT4. These signals control the ignition coils to provide the best ignition timing for the driving conditions.
* Fuel pump control system
The ECM operation outputs to TERMINAL FC and controls the C/OPN relay, allowing it to control the fuel pump drive speed in response to the conditions.
* Oxygen sensor heater control system
The oxygen sensor heater control system turns the heater on when the intake air volume is low (exhaust emissions temperature is low), and warms up the oxygen sensors to improve the detection performance of the sensors. The ECM evaluates the signals from each sensor, and outputs current to TERMINAL HT1B to control the heater
- Diagnosis System
With the diagnosis system, when there is a malfunction in the ECM signal system, the malfunctioning system is recorded in the memory. The malfunctioning system can be found by reading the display (Code) of the malfunction indicator lamp.
- 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.