Ignition Coil: Testing and Inspection

Spark Check:

1. Disconnect wiring from ignition coil.
2. Using an ohmmeter measure the coil primary circuit resistance by placing one ohmmeter lead on the positive terminal and the other on the negative terminal. The resistance should be as follows:
Diamond - 1.34-1.55 Ohms
Prestolite - 1.34-1.55 Ohms
UTC - 1.34-1.55 Ohms
3. Measure the secondary resistance of the ignition coil by placing one ohmmeter lead on the positive coil terminal and the other in the high voltage output terminal. The resistance should be as follows:
Diamond - 9,000-12,200 Ohms
Prestolite - 9,400-11,700 Ohms
UTC - 9,000-12,200 Ohms
4. Measure coil insulation by placing one ohmmeter lead on the coil positive terminal and the other on the coils outer case. There should be no continuity between the case and positive terminal.
5. If resistance readings are not within specifications replace coil.