A technician finds that spark plug resistance is too high. What is the replacement threshold for spark plug wires?

The replacement threshold for spark plug wires is typically set at 30,000 ohms. This means that if the resistance in spark plug wires exceeds this level, it is generally considered indicative of a problem, such as deterioration or failure of the wires, which can lead to poor engine performance or misfiring. A resistance value above this threshold can cause a significant voltage drop, negatively affecting the spark plug's ability to ignite the air-fuel mixture effectively.

Resistive spark plug wires are designed to limit electromagnetic interference while allowing adequate current to flow to the spark plugs. If the resistance is too high, it can prevent the ignition system from functioning properly, leading to issues like hard starting, decreased engine power, and increased emissions. Therefore, measuring spark plug wire resistance is crucial for maintaining optimal engine performance, and replacing wires that exceed the 30,000-ohm threshold is standard practice in automotive maintenance.