PARTS PRIMER
Ignition System gnition components include spark plugs (usually one per engine cylinder, but some have two), spark plug wires (not used with coil-on-plug ignitions), ignition coils (single or multiple coils depending on the application), ignirequired to pass this tion module (if used), section of the P2 test: an ignition pickup (distributor systems) 1. Identify major ignition system or a crankshaft posicomponents and types of systems. tion sensor (distribu2. Identify component function and torless systems), and common reasons for replacement. on older engines a dis3. Identify related items and tools. tributor. The ignition 4. Provide basic use, maintenance, switch also is part of installation, and warranty the ignition circuit. information. Distributorless Igni-
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tion Systems (DIS) include “waste spark� DIS systems with coil packs and plug wires, Coil-On-Plug (COP) ignitions (one coil per spark plug), and Coil-Near-Plug (CNP) ignitions (one coil per plug with a short plug wire between the plug and coil). Maintenance requirements are minimal on most late engines with long-life 100,000 mile platinum or iridium spark plugs. Conventional spark plugs need to be changed every 45,000 miles, and can be upgraded to platinum or iridium for longer service life. Replacement spark plugs must have the same size, thread pitch, length as the original, but can be any brand or type of electrode. Always follow the supplier application lists for correct spark plug fitment. Plugs are preContinued on page 98