SPARK PLUG CABLE TEST
Before beginning this test, be sure to wear rubber gloves and rubber-soled shoes for safety.
- 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 & Maintenance for checking the resistance of the spark plug wires.
SECONDARY SPARK TEST
See Figures 1 and 2
- Remove a spark plug from the engine. Examine the spark plug for cracks in its insulation and replace if necessary.
- 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 vehicle).
- 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.