Primary and Secondary Ignition Waveform Analysis (Part 2)
- Current measurement on feed side vs control side
- Control voltage testing on the control wire
- Primary current ramp basics
- Open plug wire pattern in a primary ramp
- Turn-on oscillation as a coil integrity check
- Shorted secondary pattern in primary analysis
- Shorted primary pattern and CEMF loss
- Using primary ramps to verify driver / module operation
- Ford Mode $06 for misfire direction
- Cylinder contribution test for misfire identification
- Syncing coil events with firing order
- Snap-throttle testing for intermittent misfires
- Limits of primary analysis for weak secondary faults
- Secondary fault patterns: weak coil, shorted plug, open secondary
This lesson explains how to diagnose ignition system issues by analyzing current and voltage behavior. Current can be measured anywhere in the circuit, but voltage must be checked on the control wire to confirm operation. By reading waveform patterns, technicians can identify faults like open plug wires or shorted components. Understanding when the primary signal ends and the secondary begins is key to interpreting these issues.
The lesson also highlights real-world diagnostic strategies using case studies and tools like Mode 6 data to find misfires without codes. Techniques such as fuse-box amp probing and snap throttle testing help reveal intermittent problems. It emphasizes that primary waveforms don’t always tell the full story, so further testing is often needed. Accurate diagnosis comes from combining waveform analysis with practical verification methods.