Troubleshooting Engine (2-Stroke Efi); Engine Does Not Start (No Spark At Spark Plugs); Engine Does Not Start (No Fuel At Cylinders); Engine Does Not Start (Fuel Does Not Ignite) - Arctic Cat Sno Pro 120 Service Manual

Troubleshooting Engine
(2-Stroke EFI)
Problem: Engine Does Not Start (No Spark at Spark Plugs)
Condition
1. Ground connections dirty — loose
2. Throttle/ignition monitor switch malfunctioning —
ignition switch not on
3. Wiring harness shorting — disconnected
4. Emergency stop switch in DOWN position —
malfunctioning
5. Throttle/ignition monitor switch malfunctioning
6. Spark plugs fouled — damaged
7. Spark-plug caps damaged — leaking — shorting
8. High tension leads/coil loose — grounded — faulty
9. ECU/CCU faulty
10. Ignition timing sensor faulty
Problem: Engine Does Not Start (No Fuel at Cylinders)
Condition
1. Gas tank empty
2. Injector dropping resistor faulty
3. Fuel pressure regulator faulty
4. Check valve faulty
5. Fuel pump faulty
6. Fuel hose broken — pinched
7. Gas-tank vent — hose obstructed
8. Pick-up valve(s) obstructed — damaged
9. Primary compression absent
10. ECU/CCU faulty
Problem: Engine Does Not Start (Fuel Does Not Ignite)
Condition
1. ECU/CCU LED trouble code
2. Spark absent
3. Gasoline contaminated
4. Primary compression low
5. Secondary compression low
6. Engine flooded
7. Gasoline contaminated
Problem: Engine Does Not Idle
Condition
1. ECU/CCU LED trouble code
2. Injector(s) faulty
3. Fuel pressure regulator faulty
4. Air silencer obstructed
5. TPS faulty
6. Throttle body idle adjustment incorrect
Remedy
1. Check all ground connections — clean and tight
2. Replace faulty switch — turn switch on
3. Repair — replace — connect wiring harness
4. Move switch to UP position — replace throttle control
5. Adjust throttle cable tension — replace throttle body
assembly
6. Clean — replace spark plugs
7. Replace spark-plug caps
8. Service — replace high tension leads/coil
9. Replace ECU/CCU
10. Replace sensor
Remedy
1. Fill tank
2. Replace dropping resistor
3. Replace regulator — hose
4. Replace check valve
5. Service — replace fuel pump — connections — wires
6. Replace — service hose
7. Remove obstruction — replace vent — hose
8. Remove obstruction — replace pick-up valve(s)
9. Repair — replace damaged — worn engine components
10. Replace ECU/CCU
Remedy
1. Service — replace problem component
2. Check for spark — see No Spark at Spark Plugs sub-sec-
tion
3. Replace gasoline
4. Service engine
5. Service engine
6. Clear engine (hold throttle full-open)
7. Clean tank and entire fuel system
Remedy
1. Service — replace problem component
2. Replace injector(s)
3. Replace regulator — hose
4. Clean air-intake silencer
5. Replace throttle body assembly (under warranty) - replace
TPS (out of warranty)
6. Replace throttle body assembly (under warranty) - adjust
idle RPM to specifications (out of warranty)
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