KYMCO AHG5, Service Manual

Page: 363 / 363

20. EEC SYSTEM
DT X360
20-12
8. Oxygen Sensor
It uses DC-8-16V Battery Power with 4 pins: one power pin, one heater pin, one signal
output pin and one earthing pin. The sensor is installed to the front pipe of exhaust pipe to
detect the oxygen concentration of exhaust gas for determining if ECU shall instruct to
increase or reduce fuel supply for meeting waste gas emission standard of environment
legislation. When the temperature of exhaust is less than 350
℃
, the sensing portion cannot
be activated and there is no signal output, and ECU will turn on the heater inside sensor to
accelerate the temperature rise of sensor and cause the Oxygen Sensor to work normally.
In normal hours, the impedance of heater is 7.7 +/- 1.2 ohm and can be told with multimeter.
Output of sensor after the engine is warmed up is
A/F <14.7 (mixing ratio too thick) >0.7V
A/F > 14.7 (Mixing ratio too thin) <0.18V
Inspection and adjustment of emission
1. Start the engine and warm up for several minutes engine temperature 80~90
℃
, connect
the diagnostic tool to check the information.
2. Idle speed should be in standard.
3. The emission machine should be connected to the front of the exhaust pipe measure
hole. (Before Catalyst Converter)
4. Standard
：
CO:0.3~1.5 %
5. If the figure is out of range, check with the injection relative components.(For example,
injector, fuel pump…etc.)
6. If the problems insist, please check the emission related system and check if there is
any leakage from the cylinder head inlet/outlet valve.