8. Power Balance Test

8. POWER BALANCE TEST

Purpose:

NOTE:
- Before carrying out the power balance test, allow the engine to stabilize at the temperature necessary to recreate the symptom. Access the PCM and record the freeze frame data. The freeze frame data contains information which can be used to recreate original conditions that caused the symptom. Refer to Diagnostic Methods, Freeze Frame Data for more information. Freeze Frame Data
- The contributing power cylinders that immediately follow the non-contributing power cylinders in the firing order may be affected. The affected power cylinders may not be able to fully recover the crankshaft speed, causing them to display below average contributing power cylinders and to be incorrectly identified as the non-contributing power cylinder. Therefore, only the cylinders that deviate the most from the average should be identified as the non-contributing power cylinder. Single or inconsistent non-contributing power cylinder traces may be caused by a natural variation in the crankshaft speed and should be ignored.

The purpose of this test is to determine if the fuel injectors are operating correctly by observing individual cylinder contribution while carrying out the power balance test.

Power Balance Test

NOTE: Disregard any DTCs set as a result of the Power Balance Test.

- Use the scan tool to carry out the Power Balance Test.
- Monitor individual cylinder contribution and record the consistently non-contributing power cylinders.







Recommended Procedure:

Cylinder And Fuel Injector Location:

At Engine Idle Speed Test

NOTE:
- The cylinder contribution test or enhanced power balance test must be carried out while the vehicle is stationary and not in motion. At no time should manual input through the accelerator pedal occur during these tests. Do not carry out this test while driving.
- This procedure is to be carried out at engine idle speed. Concerns that are experienced at off engine idle speed or under load conditions are addressed in the Off Engine Idle Speed or Under Load Test.

- Connect the scan tool.
- Ignition ON, engine Running.
- Access the Power Balance Test.
- Evaluate each cylinders performance and compare to specification plus or minus 15 RPM.
- If the performance of all cylinders are within plus or minus 15 RPM, select the manual fuel injector balance test on the scan tool and evaluate each cylinders performance while comparing to specification plus or minus 15 RPM. If the performance of all cylinders are within plus or minus 15 RPM, no concern is present.
- If the performance of any cylinders are not within plus or minus 15 RPM, record the consistently non-contributing power cylinders and carry out the Off Engine Idle Speed or Under Load Test to continue diagnosis.

Off Engine Idle Speed or Under Load Test

NOTE:
- This procedure is to be carried out for concerns that are experienced at off engine idle speed or under load.
- Disregard any DTCs set as a result of the Power Balance test.

- Connect the scan tool.
- Ignition ON, engine Running.
- Access he FRP_DSD PID and increase the fuel pressure to between 105-113 kPa (15,000 to 16,000 psi).
- Access the Power Balance Test.
- Evaluate each cylinders performance and compare to specification plus or minus 15 RPM.
- Select the manual fuel injector balance test on the scan tool. Evaluate each cylinders performance while comparing to specification plus or minus 15 RPM.
- Record the consistently non-contributing power cylinders.

Tools Required:
Scan tool