SPARK PLUG CABLE TEST
See Figure 1
- One at a time, disengage each spark plug wire with the engine idling to check whether the engine's performance changes or not.
- If the performance does not change, check the resistance of each spark plug and wire. Refer to General Information and Maintenance for checking the resistance of the spark plug wires.
SECONDARY SPARK TEST
- Remove a spark plug from the engine. Examine the spark plug for cracks in its insulation and replace if necessary.
See Figure 2
- Connect the spark plug to its spark plug wire.
- Ground the spark plug's outer electrode to the engine (touch the spark plug's metal body to the engine block or other piece of metal on the car).
See Figures 3, 4 and 5
- Crank the engine and look for spark across the electrodes of the spark plug.
- If a strong blue spark exists across the plug electrode, the ignition system is functioning properly.
- Repeat the test for the remaining cylinders. If one or more tests indicate irregular, weak or no spark, refer to the coil test.
- If spark does not exist, remove the distributor cap and ensure that the rotor is turning when the engine is cranked.