Ignition Coil: Testing and Inspection

PRIMARY WINDING RESISTANCE TEST

1. Disconnect electrical connector at coil.
2. Set ohmmeter to x1 scale.
3. Connect ohmmeter across coil positive and negative terminals.
4. If ohmmeter reading is not .3-1.0 ohm, replace coil.

SECONDARY WINDING RESISTANCE TEST

1. Disconnect electrical connector at coil.
2. Disconnect coil secondary wire.
3. Set ohmmeter to x1000 scale.
4. Connect ohmmeter across coil negative terminal and the secondary high voltage terminal.
5. If ohmmeter reading is not 8000-11,500 ohms, replace coil.

IGNITION COIL OUTPUT (RESERVE) TEST

1. Connect suitable engine analyzer, equipped with oscilloscope, according to manufacturer's instructions.
2. Start engine.
3. Select a secondary, superimposed pattern with a 5 millisecond (5 ms) sweep.
4. Observe burn line on the screen. Burn time must be 1 ms-2 ms, indicating that there are sufficient coil reserves to fire plugs under any conditions. Do not operate engine with a spark plug wire disconnected. Such operation will result in damage to ignition system components.