Corrado V6-2792cc 2.8L DOHC (1992)
Basic Injection Time
Basic fuel injection time is calculated from the mass air flow sensor signal and engine speed signal. Injector opening time and duration is then
modified using other input signals regarding the engine's operating conditions.
Cold Start
During cold start operation a temperature related quantity of fuel is injected once per crankshaft revolution for up to five crankshaft revolutions.
The quantity of fuel is in excess of the normal injected quantity. After five revolutions, the high initial fuel quantity is reduced on an rpm-related
basis. This is accomplished in the Control Module by start-up recognition.
Start-up recognition is permanently programmed in the Engine Control Module and is temperature and speed dependent. After the start-up
recognition threshold (600 - 800 RPM) has been reached, injection takes place only once every other crankshaft revolution.
Warm-up Operation
The Engine Control Module uses the after-start warm-up function, which is mapped and controlled up to a Engine Coolant temperature of 158°F,
to determine the fuel injection quantity and timing during the warm-up phase. The Control Module compares and evaluates input signals from the
Engine Coolant temperature sensor and the engine speed signal against fixed values in its program.
The system also recognizes a repeat start and reduces the injected quantity of fuel to avoid an over-rich condition in the event of a restart.
Normal Operating Temperature
When the engine reaches normal operating temperature (above 158°F) the basic fuel injection time is calculated from the mass air flow sensor
signal, the engine speed signal, and the Heated Oxygen Sensor signal. The Heated Oxygen Sensor signal is used as a correction factor to obtain
the optimum air/fuel mixture for reduction of pollutants and maximum engine performance.
FUEL DELIVERY CONTROL
Operation of the main fuel pump is controlled through a relay which is energized by the Motronic Control Module. The relay is energized only
during engine cranking or while the engine is running. The Engine Control Module uses the engine speed signal as an input for fuel pump control.
For the wide open throttle operation, the top line of the basic ignition map is selected. This full-load characteristic is programmed with engine
knock limits taken into consideration.
For very high ambient temperatures the ignition is retarded as a function of engine and intake air temperature.
IDLE SPEED CONTROL
Idle speed is electronically controlled by the Engine Control Module depending on engine coolant temperature and load signals.
ON-BOARD DIAGNOSTICS
In the event of a system malfunction, circuit information is stored in the internal memory of the Engine Control Module.
The Engine Control Module will give priority to those items which can cause the vehicle to exceed exhaust emission standards. In addition to
being stored in memory, an emissions-related failure will cause the "Check Engine" light to illuminate on the instrument cluster.
ADAPTIVE CONTROL
The Engine Control Module has adaptive idle speed, throttle position, and air/fuel mixture capabilities. The Control Module continuously
compares the programmed data, for idle control and air fuel mixture, with the input values.
If a deviation occurs, the new input values are superimposed and stored in the programmed data map. As a result, new output signals are sent to
the idle control valve, and or to the injectors. This allows the Engine Control Module to correct the idle speed, or injector pulse width for break-in
wear or slight air leaks which might occur in the systems.
If power is interrupted to the Control Module, new adaptation takes place within several minutes of engine operation.
