Engine Management System Information

(derived from Speed Triple T509 (885cc) & 955cc manual model 1997 - 2001, other models may vary)

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System Description (Speed Triple T509 (885cc) & 955cc, model 1997 - 2001)

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Goto Speed Triple 955i model 02 - 04     Goto Speed Triple 1050    Goto  Daytona 675     Goto  Rocket III

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Each model 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 fuelling requirements for all engine speeds and loads. In addition, the system has hardware diagnostic functions similar to the US state of California requirements for on-board diagnostics (OBDII). This function ensures that, should a malfunction occur in the 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 by a Triumph dealer 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 (varies by year and model)

Intake air temperature sensor - situated in the airbox, between the air filter element and the Air intakes at the front
of the airbox. Because 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 in the airbox, between the air filter element and the throttle butterflies- on
all models equipped with the MC 2000 ECM. The ECM MC 1000, the air pressure sensor located directly in the ECM  and is connected to the airbox via a hose. The barometric pressure sensor measures the air pressure in the airbox.
From this measurement the air density is calculated, and when added to other inputs to the ECM, the engine load is calculated. With this information, the amount of fuel per injection is adjusted to suit the prevailing conditions.

 

Crankshaft position sensor - situated inside the right hand engine cover. The crankshaft position sensor detects movement of a toothed wheel attached to the right hand end of the crankshaft. The wheel has 21 teeth which are evenly spaced, and one triple length tooth next to a triple length gap. The triple length tooth/gap 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.

Because each cylinder fires once per two revolutions of the crankshaft, it is not possible to determine by crankshaft position alone which cylinder is approaching top dead centre on a firing stroke and which is on an exhaust stroke.
To do this,
the ECM takes a further input from a camshaft position sensor.

 

+Camshaft position sensor + - situated in the cam cover. The sensor detects a feature on the camshaft which rotates once per engine firing stroke. The combination of crankshaft and camshaft position sensor inputs allows the ECM to determine which cylinder is on its firing stroke and which is on its exhaust stroke. In this way, the correct point of ignition for each cylinder is determined.

+ Removed from later models and the system reconfigured to operate without these sensors.

 

Engine coolant temperature sensor - situated in the thermostat housing above the airbox.  Coolant temperature information, received by the ECM, is used to optimise fuelling at all engine temperatures and to calculate hot and
cold start fuelling requirements.

  

Throttle position sensor - situated at the right hand end of the throttle spindle. The throttle position sensor gives a reading in the fully closed position and all other throttle opening angles are calculated using the fully closed position
as a base. Throttle angle is used by the ECM to determine fuelling requirements for all throttle positions.

 

+Vehicle speed sensor + - situated at the rear wheel. The vehicle speed sensor detects movement of the rear disc bolts which rotate at the same speed as the rear wheel. By comparing engine speed (as measured by the crankshaft sensor) with the actual vehicle speed, a determination of which 'gear is selected can be made. Fuelling, air flow and ignition requirements are then adjusted according to gear position. In addition, the vehicle speed sensor input is also used as part of the mechanism which engages the idle speed control system.

+ Removed from later models and the system reconfigured to operate without these sensors.

 

Neutral switch - situated in the gearbox. The neutral switch indicates when the transmission is in neutral. In addition, the neutral switch provides an interlock facility preventing the rider from riding off with sidestand down. If a gear is selected with the sidestand down, the supply to the ECM is removed causing the engine to cut out.

 

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 or the clutch lever, which also has a switch, is pulled to the handlebar.

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System Actuators  (varies by year and model)

In response to signals received from the sensors, the ECM directs messages to a series of electronic and electro-mechanical actuators. The function and location of the actuators is given below.

 

Idle Air Control System - located below the airbox adjacent to the throttle bodies or, on later models, inside the airbox. The system comprises an air control valve fitted with a stepper motor. The system has a controlling influence over the following:

 

  • Idling.
  • Induction air supply during engine overrun.
  • Air/fuel ratio correction when operating at altitudes above sea level.
  • Cold and hot start air/fuel ratio correction.

 

When in operation, the stepper motor opens the air control valve by a variable distance, allowing a controlled supply of air to flow along a series of pipes, into the induction system. The air is fed to a point between the throttle plates and the inlet valves.

 

Idling -  When the engine is idling, the stepper motor opens the idle air control valve allowing air to be fed to the engine even though the throttles are closed. The distance that the idle air control valve is opened is controlled by the ECM using information received from the coolant temperature sensor, barometric pressure sensor etc. Idle air fuel ratio is adjusted by feeding more or less air to mix with the fuel supplied by the injectors.

 

Overrun -  During overrun conditions, where air flow into the cylinder is very low, the idle air control system feeds additional air to the induction system allowing normal air/fuel ratios to be maintained. Without the additional air flow, incomplete combustion may take place which could cause unburnt fuel to collect in the exhaust system resulting in backfiring when the throttle is re-opened.

 

Altitude correction - If the vehicle is operated at high altitude, the reduced air density will be compensated for by varying the amount of air fed to the engine via the idle air control system. For example, at high altitudes, the idle air control system feeds a greater volume of air to the induction system to compensate for the air's reduced oxygen content.

 

Cold and hot start - Except in very cold conditions where a small amount of throttle opening aids cold start performance, the engine is usually started with the throttle in the closed position.  The idle air control system regulates the start-up air supply to the induction system.

 

Canister purge valve (California models only) - situated in the vapour return line between the carbon canister and the throttle. 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. If the valve was not pulsed, all the stored vapour would immediately be drawn into the engine briefly causing a rich mixture and very high emissions.

 

Injectors - located in the throttle body assembly. The engine is fitted with 3 twin-jet injectors which are targeted as close as possible to the back face of the inlet valves. The spray pattern of the injectors is fixed but the length of time each injector remains open is variable. The duration of each injection is calculated by the ECM using data received from the various sensors in the system.

 

Plug top ignition coils - mounted directly onto the top of each spark plug. 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.

 

The coils may be operated in two modes. During normal operation (engine running) the coils spark once every 720 ° of crankshaft rotation (once every firing stroke).

 

If the camshaft sensor were to fail, the crankshaft and camshaft signals would not synchronise. The ECM would not be able to resolve which was an ignition stroke and which was an exhaust stroke. To ensure continued engine operation with this fault, the coils are fired every 360° of crankshaft rotation (every firing and every exhaust stroke).

 

Main power relay - situated adjacent to the ECM, beneath the motorcycle seat. When the ignition is switched on, the main power relay is powered up to provide a stable voltage supply for the ECM.

 

When the ignition is switched off, the ECM holds the main power relay on so that it can carry out the power down procedure which includes:
 

  • writing data to the ECM memory,
  • referencing the position of the idle air control valve stepper motor,
  • running the cooling fan until the engine is sufficiently cool.

 

Once all the power down procedures have been carried out, the main power relay is turned off.

 

Fuel pump - located inside the fuel tank. The electric pump delivers fuel into the fuel system, via a pressure regulator, at a constant 3 bar pressure. The pump is run continuously when the engine is rotating 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.

 

 

Cooling fan - located in front of 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. If the engine is switched off when the fan is running, the fan will continue to run until the temperature has been reduced to a normal level.

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