Fi System - Yamaha 2011 FZ8NA(C) Service Manual

EAS39P1102

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 324 kPa (3.24 kgf/cm², 47.0 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 remain 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, sub-throttle position sensor, crankshaft position sensor, intake air pres-
sure sensor, atmospheric pressure sensor, intake air temperature sensor, coolant temperature sen-
sor, speed sensor and O
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 con-
ditions.
Illustration is for reference only.
1. Fuel pump
2. Fuel injector
3. Ignition coil
4. ECU (engine control unit)
5. Intake air temperature sensor
6. Speed sensor
7. Throttle position sensor
8. Atmospheric pressure sensor
9. O sensor
2
10.Catalytic converter
11.Coolant temperature sensor
12.Crankshaft position sensor
sensor enable the ECU to determine the injection duration. The injection
2
13.Intake air pressure sensor
14.Throttle body
15.Sub-throttle position sensor
16.Air filter case
A. Fuel system
B. Air system
C. Control system
1-3
FEATURES