Arctic Cat M 8000, Service Manual

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
NOTE: On the 8000, the ECM is coded with sym-
bols (

-

-

). When replacement of the ECM is nec-
essary, the ECM must be replaced with an ECM of
the same code.
Removing
1. Remove the expansion chamber.
2. Remove the two torx-head screws securing the rear
portion of the ECM heat shield; then remove the
shield.
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 sen-
sor, 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 determines the air temperature and calculates
the fuel/air mixture ratio. Resistance will drop as the tem-
perature 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 mea-
sures the current flow through the sensor to ground. From
this measurement, the ECM can determine the engine
coolant temperature 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 (between fuel line and mani-
fold) 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.
CAUTION
Do not replace an injector with one of a different code
symbol. Severe engine damage may occur.