Ignition Cable: Description and Operation
The
spark plug wiring used with ignition systems is a carbon impregnated cord conductor, encased in 8 mm (5/16-inch) diameter silicone rubber insulation. The silicone jacket withstands very high temperatures and also provides an excellent insulator for the higher voltage of the electronic ignition system. Silicone spark plug boots form a tight seal on the plug.
The boot should be twisted 1/2-turn before removing. Care should also be exercised when connecting a timing light or other pick-up equipment. Do not force anything between the boot and wiring. Do not pierce the secondary wire insulation. Use only equipment with an inductive pickup to check for spark plug firing. DO NOT pull on the wire to remove. Pull on the boot, or use a tool designed for this purpose.