Abstract: A device for testing ignition coils from automobile and other spark ignition engines is disclosed which is a small, handheld ignition coil tester powered by the battery of the engine's ignition system. The coil tester provides a visual indication of proper high voltage pulse generation or, in the case of improper function of the ignition coil caused by a short in the ignition coil, provides an indication of the existence of the short in the ignition coil. The coil tester includes a spark gap module which has vacuum sealed electrodes to provide an excellent visual indication of proper coil operation.