The RCEXL Ignition System Testing Unit is used to check the correct functioning of a complete ignition system and spark plug. The unit is connected to the ignition system in place of the hall sensor, and is powered by the hall sensor supply voltage. When the ignition system is switched on, and LED lights to show that the unit has been connected with the correct polarity and the unit is running. It generates a stream of pulses which simulate the hall sensor output. The engine speed simulation is adjusted by turning a knob on the face of the unit. The scale is calibrated in divisions from 400 to 20,000 rpm. The spark plug performance can also easily be seen.