Sea-doo GTX Limited iS 255 2009, Shop Manual

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Section 04 FUEL SYSTEM
Subsection 02 (ELECTRONIC FUEL INJECTION (EFI))
WARNING
If any gasoline leak and/or odor are present,
do not start the engine. Repair the leak.
SYSTEM DESCRIPTION
The electronic fuel injection system (EFI) on
this engine is based on the open-loop Bosch
ME-Motronic system. It comprises all the sen-
sors for detecting the ongoing operating from
the engine and watercraft and comprises all the
actuators that perform the required adjustment to
the engine. The ME-Motronic uses an electroni-
cally controlled throttle valve. There is no idle air
control valve (IACV). Also, this system introduces
torque management functions.
From the input signals (e.g. throttle lever, iBR
lever), the ECM acknowledges the driver demand
and convert it to engine operation through a
torque requirement by calculation of several vari-
ables. Then, the ECM controls the iTC (intelligent
Throttle Control), the injection system and the
ignition system to meet the torque requirement.
The ECM manages several engine torque require-
ments to control engine operation such as to deliv-
ering engine performance, fuel economy, meeting
emission regulations, limiting engine speed etc.
Since the ECM has several torque requirements
at the same time and even contradictory demands
(if the throttle lever is fully depressed and the iBR
lever is fully squeezed for example) it must priori-
tize the most important requirement according to
predefined conditions and then applies the proper
action by triggering the actuators.
Air Induction
Air Intake Silencer
Air is drawn through the air intake silencer located
above rear part of engine.
The air entry is above the front part of engine and
a rubber baffle is used to prevent the ingestion
of water. If water was drawn, baffles inside the
air intake silencer would separate the water from
the air. Water would then flow out through a drain
valve at bottom of the air intake silencer.
An air duct is used to bring the air to the super-
charger.
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1. Air entry behind rubber baffle
2. Air intake silencer
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AIR INTAKE SILENCER LIFTED FOR CLARITY
1. Air intake silencer
2. Air duct
3. Supercharger
An intercooler cools down the air from the super-
charger.
Intercooler
The intercooler is mounted externally of intake
manifold and is located above drive shaft.
Air that exits the supercharger has been warmed
up by the air compression. The air that enters the
intercooler is cooled down by circulating across
small tubes in which cooling water flows. The
cooling water is supplied by the jet pump. The
end result is that the air density is higher and you
get more air into the engine.
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