Knowing how to read your spark plug colors can be a valuable aid when giving your engine a tune up. Let's look at how it's done.
Your spark plug colors can let you know if your engine is firing properly, or if you're beginning to run into trouble. There are five basic spark plug colors and condition combinations to judge by.
Grey or slightly discolored spark plug colors are a good indicator that your engine is running properly. When your air and fuel ratio is just right, your spark plugs burn properly and there isn't a lot of surface build up.
Sooty black, dry spark plug colors and surface conditions would indicate your engine could have one or more problems. Your carburetor may be set too rich, so your plugs don't burn properly, leaving behind the build up. Your flame arrestor may also be too dirty to work well. Sooty spark plug colors may also indicate a problem with the ignition system causing a weak spark.
Black spark plug colors that look wet in appearance are and indication of fouling. Your oil, or possibly your gas ratio is too high for a proper mix, which keeps the plug from burning the way it should. It's also possible to get this kind of build up when you only drive in the city. Taking your car on the freeway allows it to reach higher rpm's, allowing the plugs to burn hotter and burn off the build up.
Chalky, lumpy build up spark plug colors may indicate bad fuel or an oil problem. Always be sure you are using the right grade of oil according to the owners manual. If you can rule this problem out, you might want to look for an oil leak in the combustion chamber.
If your spark plug colors look white, with bubbles or blistering, your plugs are overheating. This could be caused by a gapping or torque problem, as well as an air and fuel mix set too lean. If you can rule these problems out, check your timing, as too fast will cause your spark plugs to burn too hot.
By knowing how to read your spark plug colors, you can catch problems developing early before they do more serious damage to your engine.
