Testing Spark At Coil

Remove coil wire from distributor cap. Hold end of cable approximately 1/4" from ground. Crank engine and check for spark from coil wire. Spark should be present and constant. If not, check spark plug and coil wire resistance.
If spark is present and constant, continue cranking engine. Slowly move coil wire away from ground. As coil wire is moved away from ground, check for arching at coil tower. If arching at coil tower is present, replace coil.
If spark is good and no arching is present, secondary ignition system is producing necessary voltage. Ensure spark reaches spark plugs by checking condition of rotor, cap, spark plug wires and spark plugs. Repair or replace as necessary.