People tend to take two approaches to spark plug wires. They are either changed far too frequently or ignored. Most good quality spark plug wires will last up to 100,000 miles without needing replacement. If there is no apparent problem with the way the car performs, changing the spark plug wires will not likely improve anything.
Spark plug wires do not generally break when they are undisturbed.
Unless you or someone else damages a plug wire when changing the plugs, spark plug wires should outlast at least two sets of spark plugs. If you do have to change your spark plug wires, a few simple rules will help you through the steps to complete the job successfully.
Survey under the hood before starting the job.
Not all spark plug wires are easy to access on both ends. Some distributor caps are situated so that it is difficult to squeeze the plug wire onto the cap. On other cars, the cap will be readily accessible, but the spark plugs will be all but hidden on the back side of the motor underneath hoses, wires, and other items. Either scenario can make changing the spark plug wires very difficult for the novice mechanic. If you cannot reach the plug to change the wire, you may want to save this job for the professional.
An inexperienced mechanic should only change one spark plug wire at a time.
When watching an heavily trained and experienced mechanic change the plug wires, all of the wires will be removed at once. The mechanic will then quickly and correctly attach all of the new wires. It looks so simple. It is not a simple task for the untrained. To keep from routing the new wires to the wrong cylinders of your car, remove and replace the wires one at a time. It is critical that the wires be in the right order for the firing sequence to happen correctly as the plugs fire.
Always grip the boot and not the wire when removing the old wires.
One of the easiest ways to ruin a plug wire is to pull on the wire when trying to remove it from the distributor cap or the spark plug. By gripping the rubber boot, the wire can usually be safely removed from the spark plug. The same is true when putting the new wires onto the plugs. Use the boot to attach the spark plug wire to the plug itself. A light tug on the boot will let you know that you have secured the wire to the plug or cap.
Continue to swap the new wires for the old ones until all of them have been replaced.
When all of the spark plug wires have been replaced and the new wires are in place, the job is completed. It is important at this point that you make sure that anything that you had to loosen or remove from the engine is put back in place and tightened. Put away all of the tools that have been used on the job. It is time to start the car. If it starts and runs smoothly, the job is finished.
If the car fails to start or runs poorly, turn off the ignition.
Check all of the wire connections plus any other connections that were made to any part that you had to move to do the job. When all of the connections have been verified to be solid, try to start the car again. If the problem persists, you may need to seek out professional help if you cannot locate a specific problem under the hood.
