Engine Management System - Triumph Rocket III Service Manual

Fuel System/Engine Management
Engine Management System
System Description
The Rocket III is fitted with an electronic engine
management system which encompasses control of
both ignition and fuel delivery. The electronic control
module (ECM) draws information from sensors
positioned around the engine, cooling and air intake
systems and precisely calculates ignition advance
and fueling requirements for all engine speeds and
loads.
In addition, the system has an on-board diagnostic
function. This ensures that, should a malfunction
occur in the engine management system, the
malfunction type, and engine data at the time the
malfunction occurred, are stored in the ECM memory.
This stored data can then be recovered using a
special service tool which is mandatory for all Triumph
dealers. In this way, precise diagnosis of a fault can
be made and the fault quickly rectified.
System Sensors
• Intake air temperature sensor - situated at the
front of the intake duct, above the cam cover. As
the density of the air (and therefore the amount
of oxygen available to ignite the fuel) changes
with temperature, an intake air temperature
sensor is fitted. Changes in air temperature (and
therefore air density) are compensated for by
adjusting the amount of fuel injected to a level
consistent with clean combustion and low
emissions.
• Barometric pressure sensor - situated beneath
the motorcycle seat, in the top of the airbox. The
barometric pressure sensor measures
atmospheric air pressure. With this information,
the amount of fuel per injection is adjusted to suit
the prevailing conditions.
• Manifold Absolute Pressure (MAP) sensor -
situated at the front of the intake duct, above the
cam cover, connected to each of the three
throttle bodies by equal length tubes. The MAP
sensor provides information to the ECM which is
used at shallow throttle angles (very small
throttle openings) to provide accurate engine
load indications to the ECM. This degree of
engine load accuracy allows the ECM to make
very small adjustments to fuel and ignition which
would otherwise not be possible from throtlie
angle data alone.
• Clutch switch - situated on the clutch lever. The
clutch must be pulled in for the starter motor to
operate.
• Crankshaft position sensor - situated in the
alternator cover. The crankshaft position sensor
detects movement of a toothed wheel attached to
the alternator rotor.
The toothed wheel gives a reference point from
which the actual crankshaft position is
calculated. The crankshaft position sensor
information is used by the ECM to determine
engine speed and crankshaft position in relation
to the point where fuel is injected and ignition of
the fuel occurs.
• Engine coolant temperature sensor - situated
towards the front of the cylinder head, on the left
hand side. Coolant temperature information,
received by the ECM, is used to optimise fueling
at all engine temperatures and to calculate hot
and cold start fueling requirements.
• Primary throttle position sensor - situated at
the rear of the lower throttle spindle. Used to
relay throttle position information to the ECM.
Throttle opening angle is used by the ECM to
determine fueling and ignition requirements for
all throttle positions.
• Secondary throttle position sensor - situated
at the front of the upper throttle spindle. Used to
relay secondary throttle position information to
the ECM. Secondary throttle angle is used by
the ECM to determine secondary throttle
opening position under all engine running
conditions.
• Road speed sensor - situated in the lower
crankcase, on the left hand side. The road
speed sensor provides the ECM with data from
which road speed is calculated and displayed on
the speedometer. A vehicle speed limitation
device also receives information from the road
speed sensor.
• Lambda sensor - situated in the exhaust header
system upstream of the catalyst box. The
lambda sensor constantly feeds in formation to
the ECM on the content of the exhaust gases.
Based on this information, adjustments to air/fuel
ratio are made.
• Side stand switch - situated at the top of the
sidestand leg. If the sidestand is in the down
position, the engine will not run unless the
transmission is in neutral.
11.16
Service Manual - Rocket III