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 | 5 | 6
--- | --- | --- | --- | --- | --- | ---
1st Reading | 407 kPa (59 psi) | 407 kPa (59 psi) | 407 kPa (59 psi) | 407 kPa (59 psi) | 407 kPa (59 psi) | 407 kPa (59 psi)
2nd Reading | 241 kPa (35 psi) | 227 kPa (33 psi) | 232 kPa (34 psi) | 255 kPa (37 psi) | 241 kPa (35 psi) | 241 kPa (35 psi)
Amount of Drop | 165 kPa (24 psi) | 179 kPa (26 psi) | 172 kPa (25 psi) | 151 kPa (22 psi) | 165 kPa (24 psi) | 166 kPa (24 psi)
Average Range: 156-176 kPa (22.5-25.5 psi) | Injector OK | Faulty injector - too much fuel drop | Injector OK | Faulty injector - too little fuel drop | Injector OK | Injector OK

### Test Description

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

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. The fuel pressure should be within the specified range with the fuel pump running.

3. The fuel pressure should reach a steady value and stabilize after the fuel pump is turned OFF.

4. If the pressure drop value for each fuel injector is within 10 kPa (1.5 psi) of the average pressure drop value, this indicates that 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 example above.

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 Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) ? | -- | 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 below 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. Connect the J 34730-1A Fuel Pressure Gauge to the fuel pressure test port using the J 42242 Fuel Pressure Gauge Adapter.
2. Turn ON the ignition.
3. Energize the fuel pump with the scan tool.
4. Place the bleed hose of the fuel pressure gauge into an approved gasoline container.
5. Bleed the air out of the fuel pressure gauge.
6. Observe the reading on the fuel pressure gauge with the fuel pump running.

Is the fuel pressure within the specified range?

275-313 kPa (40-46 psi)

Go to Step 6

Go to Fuel System Diagnosis

6 | Turn OFF the fuel pump. Does the fuel pressure stabilize and remain constant within the specified range? | 240-275 kPa (35-40 psi) | Go to Step 7 | Go to Fuel System Diagnosis
7 |

1. Connect the J 39021 Fuel Injector Tester, J 39021-210 Injector Switch Box and, J 39021-360 Injector Harness Adapter to the main fuel injector connector at the rear of the plenum.
2. Set the amperage supply selector switch on the fuel injector tester to the balance test 0.5-2.5 amp position.
3. Select the injector to be tested on the injector switch box.
4. Turn the fuel pump ON then OFF using the scan tool in order to pressurize the fuel system.
5. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure stabilizes. This is the 1st pressure reading.
6. Depress the Push to Start Test button on the fuel injector tester in order to energize the fuel injector.
7. Record the fuel pressure that is indicated by the fuel pressure gauge after the fuel pressure gauge needle has stopped moving. This is the 2nd pressure reading.
8. Repeat steps 3-7 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.

Do any of the fuel injector have a pressure drop value that is either 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 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. Do any of the fuel injector still have a pressure drop value that is either 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 9 | Go to Symptoms - Engine Controls
9 | Replace the malfunctioning fuel injectors. Refer to Fuel Injector and Fuel Rail Replacement . Did you complete the replacement? | -- | System OK | --