CF MOTO CF500-5B 2009, Руководство по обслуживанию, Страница: 261 / 272

13 Troubleshooting
13 - 13
13
E rr o r s c od i ng : P2177
Self-learning value of air-fuel ratio, closed-loop control exceeds upper limit
E rr o r s c od i ng : P2178
Self-learning value of air-fuel ratio, closed-loop control exceeds lower limit
Introduction of theory and fault reason: In order to make catalytic converters for HC, CO and
NOx to maximize conversion efficiency, the air-fuel ratio of mixture should be 14.7:1. When
the engine occurs, parts manufacturing deviation, deposition of fuel colloid on fuel injector,
intake or back of valve, gas leak of intake and exhaust system, will cause the air-fuel
ratio(14.7:1) deviation in various degrees(partial dilute or partial concentration) which will
lead to emission deterioration and poor engine performance. Engine control system will
amend and self-learning fuel charge based on the extent and characteristics of air-fuel ratio
deviation. When self-learning value reach the limit of system setting (gas mixture partial
dilute or partial concentration, system amends the fuel charge constantly till Max), system
will judge that self-learning value transfinite fault.
Maintenance Tips
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The possible faults may exists as follow:
1
!
Injector clog needs cleaning
2
!
Intake and exhaust system leaks
3
!
Inlet or back of intake valve that fuel colloid accumulation of excessive need to be cleaned
4
!
Engine parts deviation
5
!
Valve clearance deviation
6
!
Fuel system pressure deviation