For 1990-2009 cars

Table 1: | Injector Balance Test Example (Typical)

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

#### Injector Balance Test Example (Typical)

Cylinder | 1 | 2 | 3 | 4
--- | --- | --- | --- | ---
1st Reading | 324 kPa (47 psi) | 324 kPa (47 psi) | 324 kPa (47 psi) | 324 kPa (47 psi)
2nd Reading | 249 kPa (36 psi) | 234 kPa (34 psi) | 255 kPa (37 psi) | 269 kPa (39 psi)
Amount of Drop | 75 kPa (11 psi) | 90 kPa (13 psi) | 69 kPa (10 psi) | 55 kPa (8 psi)
Average Range: 242-262 kPa (35-38 psi) | Injector OK | Faulty injector - too much fuel drop | Injector OK | Faulty injector - too little fuel drop

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 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.

2. The fuel pressure should be within the specified range. If the fuel pressure is not within the specified range, refer to Fuel System Diagnosis.

3. The fuel pressure should reach a steady value. If the fuel pressure does not reach a steady value, 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 | 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 | 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 more than the specified value? | 94°C (201°F) | Go to Step 4 | Go to Step 5
4 | Allow the engine to cool to less than the specified value. Is the engine coolant temperature less than 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 fuel pressure gage. Refer to Fuel Pressure Gage Installation and Removal .
2. Energize the fuel pump by using the scan tool.
3. Place the bleed hose of the fuel pressure gage into an approved gasoline container.
4. Bleed the air out of the fuel pressure gage.
5. Observe the reading on the fuel pressure gage.

Is the fuel pressure within the specified range?

301-347 kPa

(44-50 psi)

Go to Step 6

Go to Fuel System Diagnosis

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

1. Use 2 jumper wires from the J 35616-A Connector Test Adapter Kit in order to connect the fuel injector to the J 39021 Fuel Injector Tester test leads.
2. Connect the J 39021 to B+ and to ground.
3. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position.
4. Energize the fuel pump by using the scan tool.
5. Record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the 1st pressure reading.
6. Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester.
7. Record the fuel pressure indicated by the fuel pressure gage after the fuel pressure gage needle has stopped moving. This is the 2nd pressure reading.
8. Repeat step 1 through step 6 for each fuel injector.
9. Subtract the 2nd pressure reading from the 1st pressure reading for one fuel injector. The result is the pressure drop value.
10. Obtain a pressure drop value for each fuel injector.
11. Add all of the individual pressure drop values. This is the total pressure drop.
12. 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 higher or lower than the average pressure drop by the specified value?

10 kPa (1.5 psi)

Go to Step 8

Go to Symptoms - Engine Controls

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. Refer to the procedure in step 7. Does any fuel injector still have a pressure drop value that is either higher or lower than the average pressure drop by the specified value? | 10 kPa (1.5 psi) | Go to Step 9 | Go to Symptoms - Engine Controls
9 | Replace the fuel injectors. Refer to Fuel Injector Replacement . Did you complete the replacement? | -- | Go to Step 10 | --
10 | Does an engine performance concern still exist? | -- | Go to Symptoms - Engine Controls | System OK