Ignition Coil Testing

Ignition system faults may be diagnosed with the DISplus or GT1 if equipped with a Measurements Interface Box. Enter the test plan for ignition coil (a choice of four coils, 1, 2, 3, or 4 will be given). The oscilloscope will be pre-set during the test plan.

When measuring kV on cylinders 1 and 2, remember that the voltage is flowing from the outer electrode to the center and back to the coil. This will be indicated by negative voltage readings on the oscilloscope. kV's on cylinders 1 and 2. The voltage will be approximately 20% higher than on cylinders 3 and 4.

NOTE:

Secondary output in the 7- 9 kV range are normal during firing of the cylinder on the compression stroke and 3 - 5 kV for the cylinder on the wasted spark stroke.
A defective coil will influence two cylinders, a defective plug wire only influences one cylinder.