Table 1: | Fuel Injector Balance Test Example (Typical) |
Table 2: | Fuel Injector Balance Test Procedure |
Cylinder | 1 | 2 | 3 | 4 |
---|---|---|---|---|
1st Reading | 296 kPa (43 psi) | 296 kPa (43 psi) | 296 kPa (43 psi) | 296 kPa (43 psi) |
2nd Reading | 131 kPa (19 psi) | 117 kPa (17 psi) | 124 kPa (18 psi) | 145 kPa (21 psi) |
Amount of Drop | 165 kPa (24 psi) | 179 kPa (26 psi) | 172 kPa (25 psi) | 151 kPa (22 psi) |
Average Range: 156-176 kPa (22.5-25.5 psi) | Injector OK | Replace fuel injector - too much fuel pressure drop | Injector OK | Replace fuel injector - too little fuel pressure drop |
The numbers below refer to the step numbers on the diagnostic table.
The engine coolant temperature (ECT) must be below the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
If the pressure drop value for each fuel injector is within 10 kPa (1.5 psi) of the average pressure drop value, the fuel injectors are flowing properly. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading. Refer to the Fuel Injector Balance Test Example.
Step | Action | Values | Yes | No | ||||
---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||
2 | Did you perform the Fuel Injector Coil Test? | -- | Go to Step 3 | |||||
Important : DO NOT perform this test if the engine coolant temperature is above 94°C (201°F). Observe the ECT with a scan tool. Is the ECT less than the specified value? | 94°C (201°F) | Go to Step 4 | -- | |||||
4 |
Important: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
Important:
Is the fuel pressure within the specified range? | 337-379 kPa (49-55 psi) | Go to Step 5 | Go to Fuel System Diagnosis | ||||
5 |
Important: The fuel pressure will drop slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Monitor the fuel pressure gage for 1 minute. Does the fuel pressure decrease by more than the specified value? | 34 kPa (5 psi) | Go to Fuel System Diagnosis | Go to Step 6 | ||||
Important: Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. DO NOT record the higher fuel pressure value. Does any fuel injector have a pressure drop value that is more than the average pressure drop or less than the average pressure drop by the specified value? | 10 kPa (1.5 psi) | Go to Step 7 | ||||||
7 | Replace the affected fuel injector. Refer to Fuel Injector Replacement and Fuel Injector and Fuel Rail Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- | ||||
8 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK |