Secondary Spark Test
Remove a spark plug from the engine. Examine the spark plug for cracks in its insulation and replace if necessary.
Fig. Place the plugs in order on a piece of cardboard. This will aid you in determining the condition of the plugs and their corresponding cylinder
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).
Fig. A spark tester can save lots of time in determining an ignition system problem. This model allows you to adjust the gap that the spark has to jump
Fig. To test for spark at the plug, ground the body to a known good ground such as this ground strap bolt
Fig. The use of an anti-seize compound is advised for easy removal and installation of spark plugs
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.
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.
Fig. A spark plug wire tester, such as this one, can save much time in the diagnostic process