Yamaha XVS950CU 2014, Service Manual

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FEATURES
1-3
EAS5S71020
FI SYSTEM
The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains the
fuel pressure that is applied to the fuel injector at only 220–300 kPa (2.20–3.00 kg/cm², 31.3–42.7 psi).
Accordingly, when the energizing signal from the ECU energizes the fuel injector, the fuel passage
opens, causing the fuel to be injected into the intake manifold only during the time the passage remains
open. Therefore, the longer the length of time the fuel injector is energized (injection duration), the
greater the volume of fuel that is supplied. Conversely, the shorter the length of time the fuel injector is
energized (injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals that are input from the
throttle position sensor, crankshaft position sensor, intake air pressure sensor, air temperature sensor,
engine temperature sensor, lean angle sensor, speed sensor (except for ABS models), rear wheel sen-
sor (for ABS models) and O
2
sensor enable the ECU to determine the injection duration. The injection
timing is determined through the signals from the crankshaft position sensor. As a result, the volume of
fuel that is required by the engine can be supplied at all times in accordance with the driving conditions.
Illustration is for reference only.
A
1
Front Rear
16
3
4
C
13
14
15
B
10
11
5
9
8
7 6
12
17
18
2
1. Pressure regulator
2. Fuel pump
3. Fuel injector
4. Ignition coil
5. ECU (engine control unit)
6. Air temperature sensor
7. Lean angle sensor
8. ISC (idle speed control) unit
9. Throttle position sensor
10. O
2
sensor
11. Catalytic converter
12. Engine temperature sensor
13. Crankshaft position sensor
14. Intake air pressure sensor
15. Throttle body
16. Air filter case
17. Speed sensor (except for ABS models)
18. Rear wheel sensor (for ABS models)
A. Fuel system
B. Air system
C. Control system