Table 1: | Fuel Injector Balance Test Example (Typical) |
The scan tool is first used to energize the fuel pump. The scan tool is then used to pulse each injector for a precise amount of time, allowing a measured amount of fuel into the manifold. This causes a drop in system fuel pressure that can be recorded and used to compare the flow through each injector.
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 number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||
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Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
2 | Did you perform the Fuel Injector Coil Test? | -- | Go to Step 3 | |||||||||
3 |
Important:
Important:
Is the fuel pressure within the specified value? | 385-425 kPa (55-62 psi) | Go to Step 4 | Go to Fuel System Diagnosis | ||||||||
4 |
Important: The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Observe the fuel pressure gage for 1 minute. Does the fuel pressure drop more than the specified value? | 34 kPa (5 psi) | Go to Fuel System Diagnosis | Go to Step 5 | ||||||||
Notice: Refer to Fuel Injector Balance Test Notice in the Preface section.
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 either higher than the average pressure drop or lower than the average pressure drop by the specified value? | 20 kPa (3 psi) | Go to Step 6 | ||||||||||
6 | Clean the fuel injectors. Refer to Fuel Injector Cleaning . Did you complete the procedure? | -- | Go to Step 7 | -- | ||||||||
7 | Operate the vehicle in order to verify the repair. Does a driveability condition still exist? | -- | System OK |