FI SYSTEM 4-15
ECM (FI CONTROL UNIT)
The ECM is located under the seat.
The ECM consists of CPU (Central Processing Unit), memory (ROM) and I/O (Input/Output) sections. The
signal from each sensor is sent to the input section and then sent to CPU. On the basis of signal information
received, CPU calculates the volume of fuel necessary for injection using maps programmed for varying
engine conditions. Then, the operation signal of the fuel injection is sent from the output section to the fuel
injector.
The eight kinds of independent program maps are programmed in the ROM.
These eight kinds of maps are designed to compensate for differences of the intake/exhaust systems and
cooling performance.
LIGHT LOAD: When the engine is running in a light load, the fuel injected volume (time) is determined the
on basis of the intake air pressure and engine speed.
HEAVY LOAD:When the engine is running in a heavy load, the fuel injected volume (time) is determined on
the basis of the throttle valve opening and engine speed.
INJECTION TIMING
The system employs a sequential, front-and-rear-cylinder independent injection type, using the crankshaft
position sensor (signal generator) to determine the piston position (injection timing and ignition timing) and
the camshaft position sensor to identify the cylinder during operation, and these information are sent to the
ECM. This makes it possible to inject the optimum volume of fuel in the best timing for the engine operating
conditions.
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