Fi System - Yamaha V Star 950 Service Manual

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 392 kPa (3.92 kg/cm², 56.9 psi). Accordingly,
when the energizing signal from the ECU energizes the fuel injector, the fuel passage opens, caus-
ing 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 ener-
gized (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 and O
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.
1
A
Rear
Front
15
1. Fuel pump
2. Fuel injector
3. Ignition coil
4. ECU (engine control unit)
5. Air temperature sensor
6. Lean angle sensor
7. ISC (idle speed control) unit
8. Throttle position sensor
9. O sensor
2
10.Engine temperature sensor
11.Catalytic converter
12.Crankshaft position sensor
13.Intake air pressure sensor
2
B
14
13
1-3
2
5 6
7
8
C
4
16
3
9
12
14.Throttle body
15.Air filter case
16.Speed sensor
A. Fuel system
B. Air system
C. Control system
FEATURES
sensor enable the
10
11