2.2 Fault Diagnosis
Spark plug not sparking
Ignition coil
Symptom
Possible causes (Determine the cause from 1 in sequence)
When the high voltage power is too
low.
①
Inner impedance is too small. Use appointed tester to test.
②
Crankshaft rpm is too low.
③
Tester is disturbed (it is normal when more than one time’s
measured voltage is above the basic).
④
Wiring
of
ignition
system
is
poorly
contacted.
⑤
Ignition coil is no good.
⑥
Charging coil is bad. (Peak voltage measurement)
Secondary
side voltage
While no high-voltage power supply,
high voltage power is sporadic.
①
Tester is wrongly connected.
②
Poor ignition switch.
③
Connector of CDI assembly is poorly contacted.
④
Ground wire for CDI assembly is shorted or poorly contacted.
⑤
Poor charging coil (Peak voltage measurement).
⑥
Defective trigger (Peak voltage measurement).
⑦
Connector of high voltage wire is not good.
⑧
Inferior CDI assembly (after items
①
-
⑦
are tested and proved
abnormal or spark plug no sparking)
High-voltage power is normal, spark
plug no sparking.
①
Inferior spark plug or secondary leakage of the ignition coil.
②
Bad ignition coil.
Charging coil
No high-voltage power supply
①
Inner impedance is too small. Use appointed tester to test.
②
Crankshaft rpm is too low.
③
Tester is disturbed (it is normal when more than one time’s
measured voltage is above the basic).
④
Charging coil is bad. (when items
①
-
③
are proved normal)
No high-voltage power supply or
high voltage power is sporadic.
①
Defective ignition coil.
②
Defective charging coil.
Trigger
When high-voltage power supply is
too low.
①
Inner impedance is too small. Use appointed tester to test.
②
Crankshaft rpm is too low.
③
Tester is disturbed (it is normal when more than one time’s
measured voltage is above the basic).
④
Trigger is bad. (when items
①
-
③
are proved normal)
No high-voltage power supply or
high voltage power is sporadic.
①
Bad ignition coil.
②
Bad trigger.