Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

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Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Did you perform the Fuel Injector Coil Test Procedure?

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Go to Step 3

Go to Fuel Injector Solenoid Coil Test

Is the engine coolant temperature above the specified value?

94°C (201°F)

Go to Step 4

Go to Step 5

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

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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. Turn OFF the ignition.
2. Connect the J 34730-1A fuel pressure gauge to the fuel pressure test port.
3. Turn ON the ignition, with the engine OFF.
4. Install the scan tool.
5. Energize the fuel pump using the scan tool.
6. Place the bleed hose of the fuel pressure gauge into an approved gasoline container.
7. Bleed the air out of the fuel pressure gauge.
8. Again energize the fuel pump using the scan tool.
9. Wait for the fuel pressure to build.

Important: The fuel pump will run for approximately 2 seconds. Energize the fuel pump as necessary in order to achieve the highest possible fuel pressure.

10. Observe the reading on the fuel pressure gauge while the fuel pump is running.

Is the fuel pressure within the specified range?

414-455 kPa (60-66 psi)

Go to Step 6

Go to Fuel System Diagnosis

After the fuel pump stops, the fuel pressure may vary slightly, then should hold steady.

Does the fuel pressure remain constant within the specified range?

414-455 kPa (60-66 psi)

Go to Step 7

Go to Fuel System Diagnosis

1. Turn OFF the ignition.
2. Connect the J 39021 fuel injector tester, the J 39021-301 injector harness connector and the J 39021 - 210 injector switch box to the fuel meter body.
3. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position.
4. Select the injector to be tested on the injector switch box.
5. Turn ON the ignition, with the engine OFF.
6. Energize the fuel pump using the scan tool in order to pressurize the fuel system.
7. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure stabilizes. This is the first pressure reading.
8. Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester.
9. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure gauge needle has stopped moving. This is the second pressure reading.
10. Repeat steps 4 through 9 for each fuel injector.
11. Subtract the second pressure reading from the first pressure reading for one fuel injector. The result is the pressure drop value.
12. Obtain a pressure drop value for each fuel injector.
13. Add all of the individual pressure drop values. This is the total pressure drop.
14. 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

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 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

Replace the faulty fuel injectors. Refer to Fuel Injector Replacement .

Is the replacement complete?

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System OK

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