GM 19351587 Plug Wire

The spark plug wires should be checked at recommended intervals or whenever new spark plugs are installed. Begin by making a visual check of the spark plug wires while the engine is running. In a darkened garage with adequate ventilation or at night, start the engine and observe each plug wire, taking care not to come into contact with any moving engine parts. If possible, use an insulated or non-conductive object to wiggle each wire. A break in the wire will result in arcing or a small blue spark from the damaged area. Since secondary ignition voltage increases with engine speed, a damaged wire may not produce an arc at idle speed; therefore, have an assistant press the accelerator pedal to raise the engine speed to approximately 2000 rpm and check for arcing again. If arcing is noticed, replace all spark plug wires.