| Engine Tune-Up 2003 | |
| Is the tune-up dead? Do we still need to tune-up our cars and engines? The answer in a word is YES! |
Replacing Spark Plugs
Not too long ago the spark plugs were out where you could see them, even if they weren't easy to get to, you could still see them. Now they are recessed into cylinder heads or under covers. In some cases you could trace the ignition wires to the spark plug but many cars have "Coil On Plug" COP ignition coils and are almost always under a cover.
Regardless of the design, it is important to remember to note wire connections and routing. If not you may cross a wire or connection and cause more problems than you solve. If your vehicle has ignition wires, check them for heat cracks or oil soaking. If it is, it needs to be replaced. If it is a COP, it will be fairly expensive. Never pull an ignition wire off by grabbing the wire itself. Grab the boot and twist it back and forth while pulling it off. This will prevent damaging the carbon core of most ignition wires. With the spark plugs out, look at the porcelain insulator around the center electrode. If they have a coating of black carbon on them, it is an indication the air/fuel mixture is too rich and you may have a problem with a HO2S that is just good enough not to set a DTC. You can use your scan tool to determine this. If it is only one plug that has this carbon coating, it is a good indication you have a leaking fuel injector. When you go to install your new spark plugs, a thin coat of anti-seize will make taking them out next time a whole lot easier. And don't forget to torque the spark plugs to specifications and no tighter. Otherwise you may wind up stripping an aluminum cylinder head. |
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Additional information provided courtesy of ALLDATA
© 2003 Vincent T. Ciulla
