Chart 6C-4 Power Balance Check

Chart 6C-4: Part 1 Of 2:

Chart 6C-4: Part 2 Of 2:

Fuel Injector Circuit:

CIRCUIT DESCRIPTION
The Power Balance Check compares the performance of each of the cylinders by using the Powertrain Control Module (PCM) to shut off fuel injectors. This measures the performance of each cylinder by the amount of rpm drop caused by that cylinder not producing a power stroke. If proper fuel delivery has been determined, then a cylinder that does not show good performance (rpm drop) indicates either an ignition or mechanical problem.

NOTES ON FAULT TREE
1. Idle quality should get worse when an injector is disabled. Engine should miss and idle will become rough.

2. Unequal performance of cylinders during this check indicates an ignition or mechanical problem, assuming the fuel system has already been checked. The ignition system should be diagnosed prior to an engine mechanical problem.

3. If the fuel system and power balance check OK, then a possible Exhaust Gas Recirculation (EGR), Evaporative Emissions (EVAP) system, or Positive Crankcase Ventilation (PCV) system problem may exist.