Ignition Primary Voltage Wave Pattern Check
MEASUREMENT METHOD1. Disconnect the distributor connector and connect special tool (Test harness: MB991348) in between. (All of the terminals should be connected.)
2. Connect the analyzer primary pickup to the distributor connector terminal 2.
3. Connect the primary pickup ground terminal.
4. Clamp the spark plug cable with the trigger pickup.
NOTE: The wave pattern of the cylinder clamped to the trigger pickup will appear at the left edge of the screen.
Standard Wave Pattern Part 1:
Standard Wave Pattern Part 2:
WAVEFORM OBSERVATION POINTS
NOTE: Abnormal waveform examples are shown subsequently
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.
Point B:
Number of vibrations in reduction vibration section (Refer to Abnormal Waveform Example 5)
Point C:
Height of Zener voltage
ABNORMAL WAVEFORMS EXAMPLES
Example 1
- Wave characteristics Spark line is high and short.
Cause of problem Spark plug gap is too large.
Example 2
- Wave characteristics
Spark line is low and long, and is sloping. This could be a result of misfiring.
- Cause of problem
Spark plug gap is too small.
Example 3
- Wave characteristics
Spark line is low and long, and is sloping. However, there is almost no spark line distortion.
- Cause of problem
Spark plug gap is fouled.
Example 4
- Wave characteristics
Spark line is high and short
- Cause of problem
Spark plug cable is not properly connected. (Causing a dual ignition)
Example 5
- Wave characteristics
No waves in wave damping section
- Cause of problem
Layer short in ignition coil.