Q. Are all the primary ignition voltage reading reading normal?
A. Yes
Discuss the normal and abnormal about this pattern and what causes it?
The above pattern is the normal pattern for this primary circuit because it has dwell time, firing time, burn voltage and burn time. Abnormal pattern may miss one or more above configrations.
Show the detail you need to see for diagnosis.
To diagnose the above graph, we need dwell time, burning voltage, firing voltage and burn time on the graph
Discuss what the primary display or parade pattern emphasizes for diagnosis. what can it help you see?
Primary display tells us how this primary circuit play a role in spark generation in spark plug through secondary wiring. It help us to see the exact voltage pattern on ignition oscilloscope and to find the fault in it if any which is effecting the engine performance.
2. Secondary Voltage Patterns
Set up your ignition oscilloscope or lab scope to vies the secondary ignition patterns on your lab scope, with the engine warmed up and idling. (use parade mode or individual mode on each different cylinder, depending on scope available)
Record the average firing voltage for each cylinder in the chart below. Some variation is normal, just pick the average.
Record the Average Burn Time for each cylinder in the chart below
Q. Are all these secondary ignition voltage reading normal?
A. Yes
Discuss what is happening in the pattern and what it telling you about the ignition system
It shows us that to create a good spark across the air gap in the plug, we need very high voltage in very shot time.
Draw or photograph the shorted secondary ignition waveform you see now on your scope.
Discuss what is happening in the shorted ignition pattern and how the ignition pattern tell you what it is happening in the ignition system.
In this pattern, the firing voltage is very high for No. 4 plug and burn time is very low but all other three plug having low firing voltage and high burn time.
Remove the ground wire and attach the spark plug wire back on the engine so it is normal again. Run the engine a bit to clear the spark plug.
Draw or photograph the spark tester Secondary ignition waveform you see now on your scope. show the detail that is necessary for accurate diagnosis. Include time and voltages.
Discuss what happens to the ignition waveform when the spark tester is attached to the spark plug wire. What does it tell you about the ignition system?
Remove the spark tester carefully and put everything back together on the engine.
Engine run fine?
Yes.