- Inspect the coil for external leaks and arcing; replace the ignition coil if any are found. Every time an ignition coil assembly is replaced because of a burned tower, carbon tracking, arcing at the tower, or damage to the nipple or boot on the coil end of the coil wire (secondary cable), replace the cable (coil wire). Any arcing at the tower will carbonize the nipple so that placing it on a new coil assembly will invariably cause another coil failure. If coil wire shows any signs of damage, the coil wire (secondary cable) should be replaced since carbon tracing on an old cable can cause arcing and ruin a new coil assembly.
To perform this test on the coil, you have to fashion or purchase a particular jumper wire tool. You'll need two simple wires several feet long with alligator clips on the ends. A third wire must incorporate a capacitor of 0.33 MicroFarad capacitance. The materials and components needed to make up such jumpers should be available at a reasonable price in a local electronics store. Refer to the accompanying diagram for the make-up of the jumper wire tool.
- With a Digital Volt-Ohmmeter (DVOM) measure the battery voltage at the battery terminals and note it. Battery voltage must be at least 12.4 volts to adequately test the coil.
- Disconnect the coil secondary wire (the high tension cable) from the distributor cap.
- With the ignition key ON and by using the special jumper wire (refer to the accompanying diagram), hold the coil secondary cable approximately 1 / 4 in. (6mm) from a good engine ground with insulated pliers (or similar insulated tool) and momentarily touch the negative (-) terminal of the coil to ground. A strong, blue-white spark should be obtained. If no spark was obtained, proceed with the test, otherwise the ignition is functioning within normal parameters.
- Turn the ignition key OFF and on non-lean burn ignition systems, detach the 5-way electrical connector from the ignition control module. If equipped with the lean burn ignition system, disconnect