Start mode
When the ignition is turned on, the ECM turns on the fuel pump relay for 2 seconds. The fuel pump creates fuel pressure. ECM checks coolant temperature sensor (EATING) and throttle position sensor (TP) and determines the appropriate air/fuel ratio to start the engine. These ranges are 1.5 to 1 at -36X coolant temperature and 14.7 to 1 at 94X coolant temperature.
The ECM regulates the amount of fuel supplied by the injector by pulses with a constant repetition rate and adjustable duration. The amount of fuel passed by the injector into the cylinder is proportional to the duration of the control pulses.
Excess fuel removal mode
If the engine fills up with fuel, it can be removed by depressing the accelerator pedal all the way. The ECM will shut off the fuel completely by turning off the signal to the fuel injectors. The ECM maintains this injection mode for the entire time the throttle is fully open, when the engine speed is below 400 rpm. If the throttle is released to about 80% of travel, the ECM returns to start mode.
Work mode
The working mode has two kinds - «closed loop» And «open circuit».
Open loop
During the first start of the engine at a starting speed above 400 rpm, the system switches to the mode «open circuit». IN «open loop» The ECM ignores the oxygen sensor signal and calculates the air/fuel ratio based on input from the ECT sensor and the MAP sensor. The sensor stays in «open loop» before the following conditions are met:
- the oxygen sensor provides variable outgoing signal data, which is a sign of sufficient warm-up for normal operation;
- ECT sensor readings above the specified temperature;
- a certain period of time has elapsed since the engine was started.
Closed loop
The specific values for the specified parameters vary depending on the engine model and are stored in an electrically erasable programmable ROM (EEPROM). Upon reaching these parameters, the system switches to the mode «closed loop».
In mode «closed loop» The ECM calculates the air/fuel ratio (fuel injector on) based on the oxygen sensor signal. Thus, the air/fuel ratio remains between 14.7 and 1.
Overclocking mode
The ECM senses rapid changes in throttle position and air flow and supplies additional fuel.
Deceleration mode
The ECM senses a rapid change in throttle position and air flow and reduces the amount of fuel. When decelerating very quickly, the ECM may stop supplying fuel for a short period of time.
Battery voltage correction mode
When the battery voltage is low, the ECM can compensate for a weak spark from the ignition module in the following ways:
- an increase in the injector pulse width.
- increase in idle speed.
- increasing the ignition timing.
Fuel cut mode
Fuel is not supplied by the injectors when the ignition is off. This prevents the engine from running after the ignition is turned off. Also, fuel is not supplied in the absence of reference pulses from the central power source. Thus, it is possible to avoid overfilling the engine with fuel.