Abstract: A method of and an instrument for testing a breakerless ignition system for an internal combustion engine. The instrument, a self-contained portable unit, is coupled to the breakerless ignition system and several reference voltages are established. The voltage from the battery of the ignition system is compared with one of the reference voltages and an indication is provided if the voltage from the battery is sufficient to operate the breakerless ignition system. The DC voltage provided to the coil of the breakerless ignition system is compared to two established reference voltages and an indication is provided if the DC voltage provided to the coil is within an established range. Also, the width of the pulses to the coil, which pulses are ultimately used to generate the spark for the internal combustion engine, is measured and an indication is provided if the width of the pulses is sufficient to sustain a spark.