Testing typically starts with power isolation and visual inspection for cracked insulation, carbon tracks, and damaged wiring. Primary continuity and resistance are checked with a multimeter, then secondary output is verified with a proper spark tester designed for ignition systems. Measuring secondary voltage directly is avoided because ignition output is high voltage. Grounding, electrode gap, and cable condition are also checked because many ignition issues are caused by wiring faults rather than transformer failure. Replace the unit if output is weak, intermittent, or if insulation breakdown is visible.
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