Yamaha F225F Service Manual page 62

TECH
FEA
Asynchronous fuel injection
Asynchronous fuel injection is fuel injection that occurs using the timing determined necessary by
the engine ECM according to the signals from the sensors, not synchronized with the crankshaft
angle set by the engine ECM. At engine start-up or during acceleration, if the changes in the signals
from the TPS or air pressure sensor exceed a predetermined level, fuel injection is performed simul-
taneously for all of the cylinders.
In the fuel injection cutoff mode, the fuel injection is cut off while the engine speed control is being
performed. See "Engine speed control" (2-12).
Fuel injection amount compensation
The fuel injection control makes compensations to the fuel injection amount according to the engine
operating conditions. The compensations are determined according to the signals from the following
sensors.
Compensation
For changes in intake air pressure
For changes in intake air temperature
During warm-up
After start-up
For atmospheric pressure
During dashpot function operation
For changes in air and fuel ratio
During acceleration
For retarded ignition timing
Fuel injector anti-sticking control
After the engine start switch is turned to ON and before the high-pressure fuel pump starts operat-
ing, the engine ECM sends a signal once to actuate all of the fuel injectors simultaneously to pre-
vent the fuel injector valves from sticking.
2-7
Technical features and description
Corresponding sensor
Air pressure sensor
Air temperature sensor
Engine temperature sensor
Engine temperature sensor
Air pressure sensor
Air pressure sensor, LPS, SPS, and pulser coil
Air pressure sensor, engine temperature
sensor, and pulser coil
Air pressure sensor and TPS
Engine temperature sensor and pulser coil