Cylinder Power Balance Test

A Cylinder power balance test tests the power of each cylinder, measuring its power contribution. An engine analyzer or bidirectional scan tool cuts each cylinder and records the drop in RPM as each cylinder is disabled.

If an analyzer is unavailable, disconnect the injector's connector to disable the desired cylinder. Then, use a pen and pencil to record each cylinder's drop in RPM. Removing the coil's connector or spark plug boot and deactivating a cylinder's ignition too long dumps raw fuel into the exhaust, overheating the catalytic converter.

Notice the RPM drop as the cylinder is disabled. If a cylinder's drop is inconsistent with the others, this indicates a problem with that cylinder. 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.

Check with the manufacturer's specifications before removing the spark plug boot and safety first. Use a grabber or a tool when removing the plug cover. Some coils produce more than 35K volts.