GM Firebird 1982-1992 Repair Guide

Spark Plug Wires



See Figures 1 and 2

Every 15,000 miles (24,000 km), inspect the spark plug wires for burns, cuts, or breaks in the insulation. Check the boots and the nipples on the distributor cap. Replace any damaged wiring.

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Fig. Fig. 1: Number the distributor cap towers to denote correct spark plug wire installation

Every 45,000 miles (72,000 km) or so, the resistance of the wires should be checked with an ohmmeter. Wires with excessive resistance will cause misfiring, and may make the engine difficult to start in damp weather. Generally, the useful life of the cables is 45,000-60,000 miles (72,000-96,000 km).

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Fig. Fig. 2: Use the spark plug wire length to determine the appropriate resistance

It should be remembered that resistance is also a function of length; the longer the wire, the greater the resistance. Thus, if the wires on your car are longer than the factory originals, resistance will be higher, quite possibly outside these limits.

When installing new wires, replace them one at a time to avoid mix-ups. If it becomes necessary to remove all of the wires from the distributor cap or coil packs at one time, take the time to label the distributor cap/coil pack towers to denote the cylinder number of the wire for that position. When this is done, incorrect positioning of wires can more easily be avoided. Start by replacing the longest one first. Route the wire over the same path as the original and secure in place.