System Outline
The engine control system utilizes a microcomputer and maintains overall control of the engine, etc. An outline of the system is given here.
- Input Signals
- Engine coolant temp. signal system
The engine coolant temp. sensor detects the engine coolant temperature and has a built-in thermistor whose resistance varies according to the engine coolant temp. Thus the engine coolant temperature is sent as a control signal to TERMINAL THW of the engine control module.
- Intake air temp. signal system
The intake air temp. sensor is installed in the mass air flow meter and detects the intake air temperature, which is sent as a control signal to TERMINAL THA of the engine control module.
- Power steering oil pressure signal system
The power steering oil pressure is detected by the power steering oil pressure SW and is sent as a control signal to TERMINAL PSW of the engine control module.
- RPM signal system
The camshaft and crankshaft position are detected by the camshaft position sensor and crankshaft position sensor respectively. The camshaft position is sent as a control signal to TERMINAL G2+ of the engine control module, and the engine RPM is sent into TERMINAL NE+.
- Throttle signal system
The throttle position sensor detects the throttle valve opening angle, which is sent as a control signal to TERMINALS VTA1 and VTA2 of the engine control module.
- Vehicle speed signal system
The vehicle speed is detected by the ABS speed sensor and the signal is sent to TERMINAL SPD of the engine control module via the combination meter and the skid control ECU with actuator. (w/ ABS)
The vehicle speed is detected by the vehicle speed sensor installed in the transaxle and the signal is sent to TERMINAL SPD of the engine control module via the combination meter. (w/o ABS)
- NSW signal system (A/T)
The Park/Neutral position SW detects whether the shift position is in neutral or not, and sends a control signal to TERMINAL NSW of the engine control module.
- A/C SW signal system
The operating voltage of the A/C SW is detected and is input as a control signal to TERMINAL A/CS of the engine control module.
- Battery signal system
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned on, some of the cottage used for the engine control module operation is applied via the EFI relay to TERMINAL +B of the engine control module.
- Intake air volume signal system
Intake air volume is detected by the mass air flow meter, and is sent as a control signal to TERMINAL VG of the engine control module.
- STA signal system
To confirm that the engine is cranking, the voltage that is being applied to the starter motor during cranking is detected and is sent as a control signal to TERMINAL STA of the engine control module.
- Oxygen sensor signal system
The oxygen density in the exhaust gases is detected and is sent as a control signal to TERMINAL OX1B of the engine control module. To maintain stable detection performance by the oxygen sensor, a heater is used for warming the sensor. The heater is also controlled by the engine control module (HT1B).
- Engine knock signal system
Engine knocking is detected by the knock sensor and sent as a control signal to TERMINAL KNK1 of the engine control module.
- Electrical load signal system
When systems which cause a high electrical load such as the rear window defogger and taillight are turned on, a signal is input to TERMINALS ELS1 and ELS2 as a control signal.
- Air fuel ratio signal circuit
The air fuel ratio is detected and sent as a control signal to TERMINAL A1A+ of the engine control module.
- Engine coolant temp. signal system
- Control System
* SFI system
The SFI system monitors the engine conditions through the signals which are received from each sensor by the engine control module. Based on this data and the program stored in the engine control module, the most appropriate fuel injection timing is decided and current is output from TERMINALS #10, #20, #30 and #40 of the engine control module, operating the injectors (to inject fuel). This system finely controls the fuel injection in response to the driving conditions, through the engine control module.
* ESA system
The ESA system monitors the engine conditions using the signals which are received by the engine control module from each sensor. Based on this data and the program stored in the engine control module, the most appropriate ignition timing is decided and current is output from TERMINALS IGT1, IGT2, IGT3 and IGT4 of the engine control module. This output controls the ignition coil and igniter No. 1, No. 2 No. 3 and No. 4 to produce the most appropriate ignition timing for the driving conditions.
* Knock control system
The knock control system controls the gate based on the engine rotation speed and detects knocking by the peak value of the knock sensor output during the gate open period, and then adjusts it to the most suitable ignition timing according to the driving conditions.
* Evapopurge control system
This system draws the vapor stuck in the canister into the surge tank in order to avoid unbalancing the air fuel ratio. It does this by adjusting the fuel injection volume.
The signal at this time will be sent from TERMINAL PRG of the engine control module to the VSV (Purge).
- 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 display (Code) on 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 the data (Standard values) recorded in the engine control module memory or else stops the engine.