Exhaust Controlled Timing (Ect) System (800 Cc) - Arctic Cat Sno Pro 120 Service Manual

The fail-safe mode is an ECU operated engine RPM lim-
iter. When activated, the fail-safe mode will be seen as an
immediate loss of engine horsepower..
Problem: Engine loses power; no top end
Condition
1. Exhaust valves sticking in
down position
2. Cables adjusted too long
3. Regulator/Rectifier output
voltage out of tolerance
Problem: Poor acceleration; hesitation
Condition
1. Exhaust valve sticking in
up position
2. Cables adjusted too short
3. Regulator/Rectifier output
voltage out of tolerance
Exhaust Controlled
Timing (ECT) System
(800 cc)
The 800 cc models are equipped with the Exhaust Con-
trolled Timing (ECT) system utilizing an exhaust pipe
temperature sensor.
Remedy
1. Remove carbon deposits,
burrs, etc.
2. Inspect—adjust
3. Inspect—replace
Regulator/Rectifier/
stator
Remedy
1. Remove carbon deposits,
burrs, etc.—inspect/
replace return spring
2. Inspect—adjust
3. Inspect—replace
Regulator/Rectifier/
stator
 NOTE: The 800 cc has a three-stage exhaust valve
system. The stages are closed, mid-open, and full-
open. These models have a designated RPM of 4800 at
which the system is synchronized and checked by the
ECU 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 ECU 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.
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