Features; Outline Of The Fi System - Yamaha MT-03 Service Manual

Hide thumbs Also See for MT-03:
Table of Contents

Advertisement

EAS00019

FEATURES

EAS00896

OUTLINE OF THE FI SYSTEM

The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti-
mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric temper-
ature. In a conventional carburetor system, the air-fuel ratio of the mixture that is supplied to the com-
bustion chamber is created by the volume of the intake air and the fuel that is metered by the jet used
in the respective chamber. Despite the same volume of intake air, the fuel volume requirement varies
with the engine operating conditions, such as acceleration, deceleration, or operation under a heavy
load. Carburetors that meter the fuel through the use of jets have been provided with various auxil-
iary devices, so that an optimum air-fuel ratio can be achieved to accommodate the constant changes
in the operating conditions of the engine. As the requirements for engines to deliver more perform-
ance and cleaner exhaust gases increase, it becomes necessary to control the air-fuel ratio in a more
precise and finely tuned manner. To accommodate this need, this model has adopted an electroni-
cally controlled fuel injection (FI) system in place of a conventional carburetor system. This system
can achieve an optimum air-fuel ratio required by the engine at all times by using a microprocessor
that regulates the fuel injection volume according to the engine operating conditions detected by var-
ious sensors. Adoption of the FI system has resulted in a highly precise fuel supply, improved engine
response, better fuel economy, and reduced exhaust emissions. Furthermore, the air induction sys-
tem (AI system) has been placed under computer control together with the FI system in order to re-
alize cleaner exhaust gases.
1
21
1. Fuel injection system relay
2. Engine trouble warning light
3. Battery
4. Air induction system solenoid
5. Ignition coil/Spark plug
6. Fuel tank
7. Idling adjustment screw
8. Fuel pump
9. Intake air pressure sensor
10. ECU
11. Lean angle cut-off switch
3
2
20
19
18
4 5 6
7
8
17
16
15
14
12. Catalytic converter
13. Air filter case
14. Intake air temperature sensor
15. Fuel hose
16. Coolant temperature sensor
17. Crankshaft position sensor
18. Throttle position sensor
19. Fuel injector
20. Spark plug
21. Air cut-off valve
1-2
FEATURES
9
10
11
12
13

Hide quick links:

Advertisement

Table of Contents
loading

This manual is also suitable for:

Mt-03 2006

Table of Contents