For 1990-2009 cars

Table 1: | Injector Balance Test Example

(1) | First Reading
(2) | Second Reading

#### Injector Balance Test Example

Cylinder | 1 | 2 | 3 | 4
--- | --- | --- | --- | ---
1st Reading | 283 kPa (41 psi) | 283 kPa (41 psi) | 283 kPa (41 psi) | 283 kPa (41 psi)
2nd Reading | 147 kPa (21 psi) | 124 kPa (18 psi) | 138 kPa (20 psi) | 159 kPa (23 psi)
Amount of Drop | 136 kPa (20 psi) | 159 kPa (23 psi) | 145 kPa (21 psi) | 124 kPa (18 psi)
Average Range: 131-151 kPa (19-22 psi) | Injector OK | Faulty injector - too much fuel drop | Injector OK | Faulty injector - too little fuel drop

### Test Description

1. The engine coolant temperature must be below the operating temperature in order to avoid irregular fuel pressure readings due to Hot Soak fuel boiling.

2. This step checks that the fuel pressure is within the specified range. If the fuel pressure is not within the specified range, refer to Fuel System Diagnosis .

3. This step checks for a steady fuel pressure reading. If the fuel pressure reading indicated is not steady, refer to Fuel System Diagnosis .

4. The fuel injectors are flowing properly if the pressure drop value for each fuel injector is within 10 kPa (1.5 psi) of the average pressure drop value. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading. Refer to the examples in the preceding table.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Was the Fuel Injector Coil Test Procedure performed? | -- | Go to Step 3 | Go to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F)
3 | Is the engine coolant temperature above the specified value? | 94°C (201°F) | Go to Step 4 | Go to Step 5
4 | Allow the engine to cool below the specified value. Is the engine coolant temperature below the specified value? | 94°C (201°F) | Go to Step 5 | --
5 | Caution: Wrap a shop towel around the fuel pressure connection in order to reduce the risk of fire and personal injury. The towel will absorb any fuel leakage that occurs during the connection of the fuel pressure gage. Place the towel in an approved container when the connection of the fuel pressure gage is complete.

1. Install the J 34730-1A fuel pressure gauge. Refer to Fuel Pressure Gage Installation and Removal .
2. Turn the ignition switch ON and then OFF, in order to energize the fuel pump.
3. Place the bleed hose of the fuel pressure gauge into an approved gasoline container.
4. Bleed the air out of the fuel pressure gauge.
5. Turn the ignition switch ON and then OFF, in order to energize the fuel pump again.
6. Observe the reading on the fuel pressure gauge.

Is the fuel pressure indicated within the specified value?

250-300 kPa

(36-43 psi)

Go to Step 6

Go to Fuel System Diagnosis

6 | Turn OFF the fuel pump. Does the fuel pressure reading remain constant? | -- | Go to Step 7 | Go to Fuel System Diagnosis
7 |

1. Disconnect the fuel injector electrical connectors.
2. Connect the J 39021 fuel injector tester power leads to B+ and ground.
3. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position.
4. Connect the J 39021 fuel injector tester to a fuel injector.
5. Turn the ignition switch ON and then OFF, in order to energize the fuel pump.
6. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure stabilizes. This is the 1st pressure reading.
7. Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester.
8. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure gauge needle has stopped moving. This is the 2nd pressure reading.
9. Repeat steps 4 through 8 for each fuel injector.
10. Subtract the 2nd pressure reading from the 1st pressure reading for one fuel injector. The result is the pressure drop value.
11. Obtain a pressure drop value for each fuel injector.
12. Add all of the individual pressure drop values. This is the total pressure drop.
13. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop.

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?

10 kPa (1.5 psi)

Go to Step 8

Go to Symptoms

8 | Notice: Do not repeat any portion of this test before running the engine in order to prevent the engine from flooding. Re-test any fuel injector that does not meet the specification. Follow the procedures in step 7. Does any fuel injector still 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? | 10 kPa (1.5 psi) | Go to Step 9 | Go to Symptoms
9 | Replace any faulty fuel injector(s). Refer to Fuel Injector and Fuel Rail Replacement . Is the action complete? | -- | System OK | --