Spark Plug Wire
The spark plug wires used by your car engine to transport just the right amount of electricity into various electrical components and accessories are quite durable. They don't really move around so they don't tend to wear out fast unlike a moving component such as a wheel or a serpentine belt. However, the materials that make up each plug wire (insulator, plug, connectors, etc.) can all wear out over time because of frequent exposure to electricity and extreme heat. Once a single wire goes bad, your car's entire electrical system can go haywire. This will then cause your vehicle to exhibit the following symptoms:
Engine surging is when your car experiences brief electrical bursts that are followed by poor or non-existent electrical flow. This problem is a very common sign of a spark plug wire that have cracked or broken insulation. With worn-out insulation, the busted wire creates electrical resistant and causes irregular electrical flows or surges.
Engine power loss
Because your car engine relies on spark plug wires to fire up, a busted wire can cause the engine to perform poorly. Without enough electricity, the combustion process suffers. This will then lead to significant loss of engine power.
Engine hesitation is when the engine stalls or hesitates when you speed up. One possible culprit for this is a spark plug wire that has a cracked covering or has worn-out internal components. Once the internal or external parts of the wire are damaged, the faulty wire causes electrical interference that disrupts the regular electrical flow from the battery to the spark plugs.
Another common sign of a busted plug wire is engine misfire, an occurrence that features erratic engine performance. This is usually caused by incomplete engine combustion due to a number of reasons, one of which is a bad plug wire.
Troubleshooting a faulty spark plug wire
If your car shows many of the signs listed above, you need to troubleshoot your car to confirm if the culprit is indeed a faulty plug wire. Here's how to troubleshoot:
1. Perform a physical inspection
A faulty plug wire will usually leave an obvious trail. Aside from the symptoms above, take a closer look at each wire and search for signs of physical damage. These include burn marks, tears, cuts, holes, and scratches. Corrosion along the spark plug, coil, and boot is also an obvious sign of a worn-out wire.
You can also switch on the engine and look out for electrical arcs or listen for a weird, snapping noise coming from under the hood. These are sure signs of a high-volt electrical leak.
2. Do a wire resistance test.
Using an OHM meter or voltmeter, test the wire resistance and see if it's within the manufacturer's recommendations. Simply connect the probes of the voltmeter to the wire lead, making sure that the probes come in contact with the metal parts of the wire. If the reading goes beyond the range indicated in your car's manual, then you need to replace a spark plug wire.