Car Repair World

Ford F-350 Ignition Coil Replacement procedure TESTING Ignition Coil Test The ignition coil must be diagnosed separately from the rest of the ignition system. Primary resistance is measured between the two primary (low voltage) coil terminals, with the coil connector disconnected and the ignition switch off. Primary resistance should be 0.3-1.0 ohms. On Dura Spark ignitions, the secondary resistance is measured between the BATT and high voltage (secondary) terminals of the ignition coil with the ignition  OFF  , and the wiring from the coil disconnected. Secondary resistance must be 8,000-11,500 ohms. If resistance tests are okay, but the coil is still suspected, test the coil on a coil tester by following the test equipment manufacturer's instructions for a standard coil. If the reading differs from the original test, check for a defective wiring harness. Ignition Coil Primary Circuit Switching Insert a small straight pin in the wire which runs from t...

Dura Spark II System GENERAL INFORMATION See Figures 1 and 2 Fig. Fig. 1: Distributor assembly Fig. Fig. 2: V8 type electronic distributor components With the ignition switch  ON  , the primary circuit is on and the ignition coil is energized. When the armature spokes approach the magnetic pickup coil assembly, they induce the voltage which tells the amplifier to turn the coil primary current off. A timing circuit in the amplifier module will turn the current on again after the coil field has collapsed. When the current is on, it flows from the battery through the ignition switch, the primary windings of the ignition coil, and through the amplifier module circuits to ground. When the current is off, the magnetic field built up in the ignition coil is allowed to collapse, inducing a high voltage into the secondary windings of the coil. High voltage is produced each time the field is thus built up and collapsed. When DuraSpark is used in conjunction wi...