Arctic Cat 2014 XF 2-STROKE Service Manual Download

Page: 96 / 196

3. Disconnect the wire harness leads from the ECM;

then remove the two cap screws securing the ECM.

Remove the ECM.

Installing

1. Secure the ECM to the chassis using the existing cap

screws; then connect the wiring harness to the ECM.

2. Secure the front of the ECM heat shield into the tabs;

then secure the back of the ECM heat shield using

the existing torx-head screws. Install the expansion

chamber.



NOTE: Make sure all connectors are clean and tight.

Apply dielectric grease to all connectors.

AIR TEMPERATURE SENSOR

This sensor detects air temperature entering the air

silencer and engine. The ECM sends current to this sensor,

and (depending on the temperature) the sensor will pass a

certain amount of current through the sensor to ground.

The ECM measures how much current passes through the

sensor to ground. From this measurement, the ECM deter-

mines the air temperature and calculates the fuel/air mix-

ture ratio. Resistance will drop as the temperature rises.

Removing

1. Disconnect the wiring harness from the air tempera-

ture sensor.

2. Using a flat-blade screwdriver, pry the sensor end to

end to remove it from the air silencer. Account for

two push pins.

Installing

1. Place the sensor into position in the air silencer and

secure with push pins.

2. Connect the wiring harness to the air temperature

sensor. Secure the sensor wires with cable ties so

they do not rub on any other components.

COOLANT TEMPERATURE SENSOR

This sensor detects coolant temperature. The ECM measures

the current flow through the sensor to ground. From this mea-

surement, the ECM can determine the engine coolant temper-

ature and calculate the correct fuel/air mixture ratio.



NOTE: If the coolant temperature rises above 75° C

(167° F), the temperature sensor starts to richen the fuel
mixture. At this time, the check engine light will flash
constantly. Once the engine coolant temperature
reaches the specified temperature 90° C (194° F), the
temperature sensor will signal the ECM to go into the
rich mode to protect the engine while overheating. At this
time, the check engine light will be constantly on.

THROTTLE POSITION SENSOR

This sensor is a potentiometer (essentially, a resistor).

This sensor transforms the throttle-valve position into

output voltage to the ECM. In addition, the sensor detects

the opening or closing speed of the throttle valve and

feeds that rate of voltage change to the ECM.



NOTE: The input from the throttle position sensor is

one of the main inputs for the ECM calculation of fuel/
air mixture ratio.

IGNITION TIMING SENSOR

This sensor is triggered by teeth precisely mounted to the

flywheel flange. Each time a tooth rotates past the sensor,

a signal is sent to the ECM. From this signal, the ECM

determines ignition and injection timing and RPM.

BAROMETRIC PRESSURE SENSOR

This sensor is part of the ECM. Its purpose is to sense

atmospheric pressure. From this information, the ECM

determines the correct fuel/air mixture ratio.



NOTE: The sensor is not replaceable. If it should

fail, the ECM must be replaced.

FUEL INJECTORS

A fuel injector is an electromagnetic injection valve con-

trolled by a signal from the ECM. The coil used in the

injector is a high-pressure resistance type. The ECM

determines the optimum fuel injection time and duration

based on signals from the sensors.

When voltage is sent to the fuel injector, it energizes the

coil and opens the needle valve, thereby injecting fuel.

Because the fuel pressure (pressure differential between

fuel line and manifold) is kept constant, the amount of

fuel injected is determined by the duration of time the

valve is open and manifold pressure.

8000

The injectors are coded with symbols (







) and are

color-coded yellow and green. When replacement of a

fuel injector is necessary, the injector must be replaced

with an injector of the same code symbol and color.

SNO-738

Removing

CAUTION

Do not replace an injector with one of a different code
symbol. Severe engine damage may occur.

WARNING

Since the fuel supply hose may be under pressure, remove
it slowly to release the pressure. Place an absorbent
towel around the connection to absorb gasoline; then
remove the hose slowly to release the pressure. Always
wear safety glasses when removing the fuel hoses.