Car parts in ignition systems before 1980 had several moving parts, and the more these parts had to move, the more quickly they would wear out. The spark plugs, rotor, contact points and coil were often sold together, and the whole shebang would be replaced once a year, or around 15,000 miles (24,140 kilometers). Ignitions that were heavily used, like those in delivery vans or taxis, often needed to replace these worn-out auto parts even more often.
The need for multiple spark plug wires to connect each of the plugs to the one coil that served the whole system could often affect auto part longevity. While spark plug wires could last as long as 60,000 miles (96,561 kilometers), according to Jim Houser of Hawthorne Automotive Clinic, the position of the wires in the engine made a significant difference. If they were close to the hot exhaust manifold, for example, they'd need to be changed out a lot sooner.
For decades, all the car part information a person could find would recommend the replacement intervals for ignition system components, usually at the 30-, 60-, or 90,000-mile (48,280-, 96,561-, or 144,841-kilometer) tune-ups. But with the new coil-on-plug systems, car part longevity has nearly reached automotive infinity. There are no moving parts to wear out, but if the spark plugs spend 120,000 miles (193,121 kilometers) inside the engine, they might be extremely difficult to remove at that point.
There are a few problems that can affect a COP system, says Leslie Macaulay, an instructor in Automotive Service Technology at Portland Community College, like a fuel mixture that's either too rich or too lean. Too rich means too much gas or oil is burning, and it can foul even iridium-tipped plugs. Too lean means there isn't enough fuel, and again, the spark plugs suffer. But with normal operation, Macaulay says, modern spark plugs go a long time.
Auto part information and advances in technology have made maintenance of today's autos easier than ever. Keep reading to find out what kind of ignition system maintenance still needs to be performed.