The numbers below refer to the step numbers on the diagnostic 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
| Did you perform the Fuel Injector Coil Test?
| --
| Go to
Step 3
| Go to
Fuel Injector Solenoid Coil Test
|
3
|
Important : DO NOT perform this test if the ECT is above 94°C (201°F).
Observe the ECT parameter with a scan tool.
Does the scan tool indicate that the ECT parameter is less than the
specified value?
| 94°C (201°F)
| Go to
Step 4
| --
|
4
|
Important: Verify that adequate fuel is in the fuel tank before proceeding with
this diagnostic.
- Turn OFF the ignition.
- Install the fuel pressure gage. Refer to
Fuel Pressure Gage Installation and Removal
.
- Turn ON the ignition, with the engine OFF.
Important:
| • | The fuel pump may need to be commanded ON a few times, in order to obtain
the highest possible fuel pressure. |
| • | DO NOT start the engine. |
- Command the fuel pump ON with a scan tool.
- Observe the fuel pressure gage, with the fuel pump commanded ON.
Is the fuel pressure within the specified range?
| 414-455 kPa (60-66 psi)
| Go to
Step 5
| Go to
Fuel System Diagnosis
|
5
|
Important: The fuel pressure may vary slightly 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 1 minute.
Does the fuel pressure decrease by more than the specified value?
| 34 kPa
(5 psi)
| Go to
Fuel System Diagnosis
| Go to
Step 6
|
6
|
- Disconnect the multi-way harness connector of the fuel injectors.
- Connect the J 39021
Fuel Injector Tester, J 39021 - 210
Injector Selector Switch Box, and J 39021-301
Injector Test Adapter to the fuel
meter body.
- Set the amperage supply selector switch on the fuel injector tester
to the Balance Test 0.5-2.5 amp position.
- Command the fuel pump ON and then OFF with a scan tool.
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.
- Record the fuel pressure indicated by the fuel pressure gage after
the fuel pressure stabilizes. This is the first pressure reading.
- Energize the fuel injector by depressing the Push to Start Test
button on the fuel injector tester.
- Record the fuel pressure indicated by the fuel pressure gage after
the fuel injector stops pulsing. This is the second pressure reading.
- Repeat steps 1 through 7 for each fuel injector.
- Subtract the second pressure reading from the first pressure reading
for one fuel injector. The result is the pressure drop value.
- Obtain a pressure drop value for each fuel injector.
- Add all of the individual pressure drop values. This is the total
pressure drop.
- 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 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 7
| Go to
Symptoms - Engine Controls
|
7
| Clean the fuel injectors. Refer to
Fuel Injector Cleaning
.
Did you complete the repair?
| --
| Go to
Step 8
| --
|
8
| Operate the system in order to verify the repair.
Did you correct the condition?
| --
| System OK
| Go to
Symptoms - Engine Controls
|
