Cavalier Coil Pack Replacement

Category: Auto Tuning

coil pack

 If a coil pack dies the car will generally quit and won’t restart, especially if the engine is warm. When first diagnosing the engine remove a spark plug and still connected to the spark plug wire, lay it on the engine. Crank the engine over and look for spark to jump across the plug. This is a 1999 Chevy Cavalier with a 2.2 liter 4 cylinder engine. The engine quit quickly and would not restart on this car. The next step was to check the 12 volt power wire that powers the coil pack. After disconnecting the plug and checking the wire, there was power to the coil pack. This eliminated the possibility of a fuse or the ignition switch.

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How to test an ignition coil

Category: Auto Tuning

A standard car’s distributor ignition coil can be tested by checking the ohms reading. Ohms can be read on a volt/ohms meter. Ohms is a unit of measure for the resistance that a wire or coil has. Ignition coils should be measured on the primary coil between batt and tach terminals. The batt is the coil ground. To check the secondary coil, check the ohms between the batt terminal and where the coil output wire plugs into. If the ohms read zero the coil connection is broken and the coil is no good. An open coil reading zero is the usual culprit of coils. Don’t test through the output wire though. The primary coil should read between .7 ohms and 1.7 ohms, if outside this range replace it. The secondary coil should generally read between 7.5K ohms and 10.5K ohms. If the ohms are not within the specified range for that paticular car, replace the coil. Coil resistance will also change and vary if the coil is hot or cold. This a generalized ohms range that fits most distributor coils. Another thing to remember is that sometimes a coil will only read bad after it gets hot. It may work intermittently after it gets hot also. Coil packs will generally read around .3 to 1.5 ohms on the primary side and 12.5K to 13.5K ohms on the secondary side. These figures will get you reasonably close to where the coil’s ohms need to be to work properly.