Yamaha F225F Service Manual page 61

Synchronous fuel injection
Synchronous fuel injection is fuel injection that occurs using a fixed timing, which is synchronized
with the crankshaft angle set by the engine ECM according to the signals from the pulser coil.
Fuel injection
Fuel injection timing
type
Simultaneous All cylinders according to
fuel injection the fuel injection setting
in the start-up data
mode
Group fuel Each cylinder group (#1
injection in the and #4, #2 and #5, and #3
start-up mode and #6) at BTDC 430°
(BTDC 70° according to the
exhaust TDC)
Group fuel Each cylinder group (#1
injection in the and #4, #2 and #5, and #3
normal and #6) according to the
operating exhaust and compression
mode TDCs
2 times for every 2 turns of
the crankshaft
Sequential Each cylinder according to
fuel injection the injection completion
in the normal timing, which is set using
operating the exhaust TDC
mode
Example: Group fuel injection in the start-up mode
#1 Compression
Intake
#2
Exhaust
#3
Exhaust
#4
Combustion
#5
Compression
#6
Pulser coil
signal
Cam position
sensor (EX)
signal
Injection #1
Injection #2
Injection #3
Injection #4
Injection #5
Injection #6
Combustion
Compression
Intake Compression
Intake
Exhaust
Combustion Exhaust
Fuel injection amount
According to the fuel
injection setting data when
the engine temperature is
78–80 °C (172–176 °F) or
more and the fuel injection
setting data when the
engine temperature is less
than 78–80 °C (172–176
°F)
According to the fuel
injection setting data for the
fuel octane rating and the
knock learning value, which
are recorded in the engine
ECM
Exhaust
Combustion Exhaust
Combustion
Compression
Intake Compression
Intake
Electronic control system
Condition
Until cylinder
identification is
completed by the
pulser coil
Until engine
starting is detected
(500 r/min or more)
Until cylinder
identification is
completed by the
cam position
sensor (PORT EX)
After cylinder
identification is
completed by the
cam position
sensor (PORT EX)
Intake Compression
Intake
Exhaust Intake
Combustion Exhaust
Combustion
Compression
0
1
2
3
4
5
6
7
8
9
10
A
2-6