What is the most common reason for engine misfires

What is the most common reason for engine misfires

Whether you're an automotive technician or a hobbyist, if you've worked on a car you've probably encountered a misfire at some point. They can be a real nuisance but, as with most problems, the more you know, the better off you'll be. From spark plugs to ignition coils, there are many different reasons why an engine may not start.

The most common causes of misfires are worn spark plugs, improper installation and maintenance, faulty ignition coils, carbon buildup, faulty spark plug wires and vacuum leaks. Not surprisingly, spark plugs are one of the most common causes of misfiring, but advances in the metallurgy of these components are constantly improving their performance. In particular, fine-wire iridium spark plugs have been designed to allow for more specific ignition and fewer misfires.

When it comes to spark plug-related misfires, the main cause is worn or improperly installed spark plugs. Spark plugs conduct current from the ignition system to the combustion chamber and ignite the fuel/compressed air mixture. If the spark plugs are not tightened properly they can leak air and alter the air/fuel ratio, and if improperly installed they can cause air gap problems.

In the case of ignition coils, a misfire code is issued when a fault occurs, but this is not necessarily the cause of the actual problem. A misfire code can be caused by anything that causes the cylinder not to fire. Therefore, a complete diagnosis must be performed to determine 100% what the cause of the misfire is.

Another common engine failure is what is known as carbon streaking or flashover. This occurs in the ignition coil, at the spark plug insulator, and is usually caused by oil, dirt, erosion or moisture grounding the spark. However, with modern spark plugs, flashover can be avoided by using multi-slotted ceramic insulators with a high alumina content.

Spark plugs can be a major cause of misfiring, but thanks to the use of iridium in the design of fine spark plug wires, misfiring has been solved as never before. The risk of misfiring is reduced because the metal is protected against heat, oxidation and corrosion.

There is no one-size-fits-all solution for misfiring. Therefore, make sure your customer has a complete misfire diagnosis. If your customer's misfire is caused by the condition of the spark plug, inform them of Iridium's options for reducing misfires.