Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Cylinder | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
First Reading | 12,000 kPa (1,740 psi) | 12,000 kPa (1,740 psi) | 12,000 kPa (1,740 psi) | 12,000 kPa (1,740 psi) | 12,000 kPa (1,740 psi) | 12,000 kPa (1,740 psi) |
Second Reading | 8,180 kPa (1,186 psi) | 7,790 kPa (1,130 psi) | 8,180 kPa (1,186 psi) | 8,180 kPa (1,186 psi) | 8,570 kPa (1,243 psi) | 8,180 kPa (1,186 psi) |
Amount Of Drop | 3,820 kPa (554 psi) | 4,210 kPa (611 psi) | 3,820 kPa (554 psi) | 3,820 kPa (554 psi) | 3,430 kPa (497 psi) | 3,820 kPa (554 psi) |
Average Range: 3,505-4,133 kPa (508.5-599.5 psi) | Injector OK | Fuel Injector - Too Much Pressure Drop | Injector OK | Injector OK | Faulty Injector - Too Little Pressure Drop | Injector OK |
Circuit/System Description
The scan tool first cranks the engine to energize the high and low pressure fuel pumps and then the injectors for a precise amount of time allowing a measured amount of fuel into the manifold. This causes a drop in fuel rail pressure that is recorded by the scan tool for each injector, and displayed in the results menu when the test is complete. The results can then be used to compare each injector to the average drop in pressure.
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 and Connector End View Reference
Scan Tool Reference
Control Module References for scan tool information
Component Testing
Fuel Injector Balance Test with Scan Tool
- Ignition ON, verify that DTC P0087, P0088, P0089, P0090, P0091, P0092, P0191, P0192, P0193, or P069E is not set.
- Ignition ON, verify that the scan tool ECT parameter is within 50°C (90°F) of the Ambient Air Temperature parameter.
- Select the scan tool Fuel Injector Balance Test function, within the Special Functions menu. Select a fuel injector to be tested and press Enter in order to begin the test.
- Repeat the test for each fuel injector in order to obtain a pressure drop value for each fuel injector.
- After all of the injectors have been tested, press Results to view the pressure drop for the injectors.
- Add all of the individual pressure drop values displayed in the results screen in order to calculate the total pressure drop. Divide the total pressure drop by the number of fuel injectors in order to calculate the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be greater than 314 kPa (45.5 psi).
| ⇒ | If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. |
| ⇒ | If the ECT is not within the specified range, allow the engine to cool before proceeding. |
Warning: The engine will crank when performing the fuel injector balance test with a scan tool. Keep hands and tools away from the engine pulleys and belts during this test.
Note: The scan tool will cause the engine to crank momentarily, then allow time for the fuel rail pressure to stabilize before the fuel injector is automatically pulsed.
Caution: Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding.
| ⇒ | If the difference between any individual pressure drop and the average pressure drop is greater than the specified value, replace the fuel injector. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
