Cylinder Power Balance Testing
An Cylinder power balance test indicates the power of each cylinder, testing its effectiveness compared to the others. The test is best performed with an engine analyzer. If an analyzer is unavailable, the technician can momentarily (a few seconds) disconnect the plug wire from its corresponding spark plug or distributor connection to disable the desired cylinder. Check with manufacturers specifications before removing the spark plug boot and remember safety first. A prolonged open in the secondary ignition system may cause damage to the coil or ignition module. The test is typically performed to locate the cylinder causing a misfire or not contributing to the engine balance and performance.
Use a grabber or a tool that will protect your hand from the shock that may result from removing the plug cover. Some coil packs produce 35K volts so be careful not to get shocked.
Notice the RPM drop as the plug wire is removed from the plug. If a cylinders RPM drop is not consistent with the others this indicates a problem with that cylinder. An engine analyzer tests each cylinder and then compares the results. The reasons for a cylinder not contributing include an ignition problem, fuel delivery, or a mechanical problem such as a faulty valve or worn piston rings.
