Arctic Cat M 8000, Service Manual

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XM024A
6. Perform steps 5-8 in Cable Adjustment in this
sub-section.
TROUBLESHOOTING
The APV system has a self-testing mode built in. Every
time that the engine is started, the servomotor will cycle
once. The ECM monitors the voltages at the servomotor
during this cycle to assure they are within operational tol-
erances.
If all voltages are within tolerance, the system is ready
for operation. If the voltages are not within tolerance, the
servomotor will cycle two more times. If the voltages
remain out of tolerance, the system will not operate.
For example, if the headlight and taillight are disabled,
the ECM will sense a high voltage condition and activate
the fail-safe mode. Adding more than 4 amps of accesso-
ries will create a low voltage condition and activate the
fail-safe mode.
The fail-safe mode is an ECM operated engine RPM lim-
iter. When activated, the fail-safe mode will be seen as an
immediate loss of engine horsepower.
Exhaust Controlled Timing
(ECT) System
These models are equipped with the Exhaust Controlled
Timing (ECT) system utilizing an exhaust pipe tempera-
ture sensor.

NOTE: The engine has a three-stage exhaust valve
system. The stages are closed, mid-open, and
full-open. These models have a designated RPM of
4500 at which the system is synchronized and checked
by the ECM for proper operation occurring once each
time the engine is started.
This system automatically adjusts the ignition timing to
provide maximum performance through a variety of
operating conditions. The ECM receives input on engine
RPM (demand) and exhaust temperature (engine condi-
tion) and adjusts the ignition timing accordingly. This
system is not adjustable and is maintenance free.
If a system fault is suspected, use an ohmmeter to check
continuity of the exhaust pipe temperature sensor located
in the expansion chamber. A reading of either 0 ohm or
infinity indicates a failed sensor.

NOTE: A disabled ECT system WILL NOT cause
engine damage; however, a failed ECT system will
have slower throttle response and may produce
slightly less top-end performance.
Problem: Engine loses power; no top end
Condition
Remedy
1. Exhaust valves sticking in
down position
1. Remove carbon deposits,
burrs, etc.
2. Cables adjusted too long 2. Inspect—adjust
3. Regulator/Rectifier output
voltage out of tolerance
3. Inspect—replace Regula-
tor/Rectifier/stator
Problem: Poor acceleration; hesitation
Condition
Remedy
1. Exhaust valve sticking in
up position
1. Remove carbon deposits,
burrs,
etc.—inspect/replace
return spring
2. Cables adjusted too short 2. Inspect—adjust
3. Regulator/Rectifier output
voltage out of tolerance
3. Inspect—replace
Regulator/Rectifier/
stator