System Actuators - Triumph Rocket III Classic Service Manual

Fuel System/Engine Management
System Actuators
In response to signals received from the sensors, the ECM
controls and directs messages to a series of electronic and
elector-mechanical actuators. The function and location of
the actuators is given below.
Primary throttle stepper motor -
situated at
the front of the throttle bodies. The primary
throttle stepper motor actuates a cam/lever
which causes variations in the closed throttle
position. Although used primarily to ensure
target idle speed is maintained, it also increases
throttle opening when the engine is cold.
Second throttle stepper motor -
situated
between the throttle bodies for numbers one
and two cylinders. In response to direction from
the ECM, the second throttle stepper motor
moves the second throttle spindle to the
position directed by the ECM. The second
butterfly epitomises engine torque by
maintaining intake air flow speed. It does not
act as a choke for cold start purposes.
Canister purge valve (California models
only) -
situated in the vapour return line
between the carbon canister and the throttle
bodies. The purge valve controls the return of
vapour which has been stored in the carbon
canister during the period when the engine is
switched off. The valve is 'pulsed' by the ECM
to give control over the rate at which the
canister is purged.
Injectors -
located in the throttle body
assembly. The engine is fitted with three
injectors. The spray pattern of the injectors is
fixed but the length of time each injector can
remain open is variable according to operating
conditions. The duration of each injection is
calculated by the ECM using data received
from the various sensors in the system.
Ignition coils -
mounted on a bracket, above
the camshaft cover. There are three coils fitted,
one for each pair of spark plugs. The ECM
controls the point at which the coils are
switched on and off. In calculating the switch-on
time, the ECM allows sufficient time for the coils
to charge to a level where a spark can be
produced. The coils are switched off at the
point of ignition, the timing of which is
optimised for good engine performance.
Main power relay -
situated behind the left
hand side cover. When the ignition is switched
on, the main power relay is powered up to
provide a stable voltage supply for the ECM.
• Fuel pump -
located inside the fuel tank The
electric pump delivers fuel into the fuel system,
Note:
via a pressure regulator, at a constant 3 bar
pressure. The pump is run continuously when
the engine is operating and is also run briefly
when the ignition is first switched on to ensure
that 3 bar is available to the system as soon as
the engine is cranked. Fuel pressure is
controlled by a regulator also situated inside the
fuel tank.
Cooling fan - located behind the radiator. The
ECM controls switching on and off of the
cooling fan in response to a signal received
from the coolant temperature sensor. When the
coolant temperature rises to a level where the
cooling effect of natural airflow is insufficient,
the cooling fan is turned on by the ECM. When
the coolant temperature falls sufficiently, the
ECM turns the cooling fan off. The fan only
becomes operational when the engine is
running. It will not operate at any other time.
• In this system, the starter lockout system
(clutch switch, neutral switch, sidestand switch)
all operate through the engine management
ECM.
11.22
Service Manual - Rocket III / Classic / Touring
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