Yamaha FJR1300R Service Manual page 39

Fuel injection compensation control
• Starting injection control
The coolant temperature is used for determining the injection duration in order to ensure proper
start ability. To suit the engine's operating conditions, the starting injection duration is determined by
applying a starting compensation coefficient to the basic injection duration, which forms the basis of
the injection duration.
(Starting injection duration = basic injection duration × injection compensation coefficient)
During starting, injection cylinder control is effected together with injection duration compensation.
To effect injection cylinder control, the injectors of all the cylinders inject fuel only once immediately
upon receiving the signals from the sensors during the cranking of the engine. This is called asyn-
chronous injection, in contrast to synchronous injection, which is a normal cylinder injection that is
effected on a cylinder-by-cylinder basis.
After the asynchronous injection is completed, and until the ECU receives signals from the cylinder
identification sensor, the injectors are actuated in pairs in sync with the signals from the crankshaft
position sensor: cylinders #1 and 4, and cylinders #2 and 3. Controlling both the injection duration
and the injection cylinders in this manner enables a precise supply of fuel in accordance with the
starting conditions of the engine.
• Starting injection duration
1 Basic injection dura-
tion
2 After-start compensa-
tion injection duration
3 Low
4 High
0
È Injection duration
É Coolant temperature
Ê Extended duration
1 - 21
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