Power Balance Test

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📖 YOUCANIC Automotive Glossary

The Power Balance Test evaluates individual cylinder contribution by selectively disabling one cylinder at a time (cutting its injector or ignition) while monitoring RPM drop. In a healthy engine, disabling any cylinder produces the same RPM drop. If disabling cylinder 3 drops RPM by 75 while others drop 150, cylinder 3 is contributing less power, indicating a mechanical or fuel delivery problem specific to that cylinder.

The YOUCANIC UCAN-II automates this — sequentially disabling each cylinder and displaying a comparison. This test is invaluable for diagnosing misfires without specific cylinder DTCs, identifying weak cylinders, and verifying repairs. Unlike physical compression testing requiring spark plug removal, power balance is non-invasive and takes minutes. However, it reveals relative contribution, not the specific cause — you still need to determine if the issue is compression, fuel, or ignition.

Synonyms:
Cylinder Contribution Test, Cylinder Balance Test
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