Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement page 645

16-46
WAVEFORM OBSERVATION POINTS
Point A: The height, length and slope of the spark line (refer to abnormal waveform examples 1, 2, 3
and 4) show the following trends.
Spark line Plug gap
Length Long Small
Short Large
Height High Large
Low Small
Slope Large
Point B: Number of vibration in reduction vibration section
(Refer to abnormal waveform example 5)
Number of vibrations
3 or higher
Except above
Point C: Height of Zener voltage
Height of Zener voltage
High
Low
ENGINE ELECTRICAL –
Condition of Compression
electrode force
Normal Low
Large wear High
Large wear High
Normal Low
Plug is fouled –
Coil, condenser
Normal
Abnormal
Probable cause
Problem in Zener diode
Abnormal resistance in
primary coil circuit
Ignition System
Concentration of Ignition timing
air mixture
Rich Advanced
Lean Retarded
Lean Retarded
Rich Advanced
– –
High tension
cable
Leak
High
resistance
High
resistance
Leak
–