Fuel Injector Balance Test with Special Tool

Fuel Injector Balance Test with Special Tool

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

Circuit/System Description

The CH-47976 Active Fuel Injector Tester (AFIT) is used to test the fuel pump, fuel system leak down, and the fuel injectors. The on screen prompts or selections will indicate the steps required to perform each of the available tests. The tester will perform all of the tests automatically and display results of the test. The results can also be down loaded for storage and printing. Refer to the User Guide, CH 47976-11 for more information.

Diagnostic Aids

* Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
* Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.

Reference Information
Schematic Reference

Engine Controls Schematics (Electrical Diagrams)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

* CH-47976 Active Fuel Injector Tester (AFIT)
* EL-39021-460 Fuel Injector Test Adapter

Component Testing

Fuel Injector Balance Test with Special Tool
1. Ignition ON, verify that the scan tool engine coolant temperature (ECT) parameter is less than 94°C (201°F).

• If the ECT is greater than 94°C (201°F) allow the engine to cool before proceeding.

2. Turn OFF all accessories.
3. Turn OFF the ignition.

Note: DO NOT connect the EL-39021-460 until prompted by the AFIT.

4. Install the AFIT. Refer to the AFIT User Guide.
5. Turn ON the AFIT and select the vehicle.
6. Turn ON the ignition and perform the Injector Test.

• If the AFIT aborts testing due to fuel pressure or fuel leak down, refer to Fuel System Diagnosis (Fuel System Diagnosis).

7. View the test results.

• If any injector exceeds the recommended tolerance, replace the injector(s).

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Fuel Injector and Fuel Rail Replacement (SFI) (Service and Repair)