Captiva

Fuel Injector Balance Test

The fuel injector balance test is performed while the engine is running at idle. The scan tool pressurises the fuel rail to a predetermined pressure before each injector is pulsed for a precise amount of time allowing a measured amount of the fuel to be injected. This causes a drop in the system fuel pressure that is recorded and used to compare each injector.

Note: 

Fuel Injector Balance Test

1. Verify the correct low side fuel pressure. Refer to Fuel System Diagnosis .

Note: The engine speed must be between 600-1000 RPM to perform this test.

2. Engine running at normal operating temperature. With a scan tool, select the Fuel Injector Balance function within the Output Controls menu.
3. Select and test an injector. Repeat for each injector in order to obtain a pressure drop value for each injector.
4. After all injectors are tested, record the fuel pressure drops.
5. Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
6. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop.
7. Multiply the average pressure drop by 0.20. This is the acceptable variance from the average pressure drop, 20 percent.

⇒	If the difference between any individual pressure drop and the average pressure drop is more than the acceptable variance, replace the fuel injector.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.