Fuel Injector Balance Test with Tech 2: Description
WARNING: This page is about a different variant/trim than selected.
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 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.
Fuel Injector Balance Test Example (Typical)
| 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 |
Fuel Injector Balance Test with Tech 2
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | - | Go to Step 2 | Go to Diagnostic System Check - Engine Controls |
| 2 | Did you perform the Fuel Injector Coil Test? | - | Go to Step 3 | Go to Fuel Injector Coil Test |
| 3 |
IMPORTANT:
DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F).
IMPORTANT:
Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
IMPORTANT:
The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
|
382-425 kPa (56-62 psi) | Go to Step 4 | Go to Fuel System Diagnosis |
| 4 |
IMPORTANT:
The fuel pressure will decrease 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 5 minutes.Does the fuel pressure decrease to less than the specified value? |
34 kPa (5 psi) | Go to Fuel System Diagnosis | Go to Step 5 |
| 5 |
NOTE:
Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding.
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.
|
10 kPa (1.5 psi) | Go to Step 6 | Go to Symptoms - Engine Controls |
| 6 | Perform the Fuel Injector Cleaning Procedure
. Did you complete the procedure? |
- | Go to Step 7 | - |
| 7 | Operate the system in order to verify the repair. Did you correct the condition? |
- | System OK | Go to Symptoms - Engine Controls |