The Fuel Injector Balance Test compares the performance of each of the
cylinder by using the PCM to shut off fuel injection. The J 39021
Fuel Injector Tester is being used
to energize the fuel injector for a precise time period. This measures the
performance of each cylinder by the amount of RPM drop caused by that cylinder
not producing a power stroke. If proper fuel delivery has been determined,
then a cylinder that does not show good performance (RPM drop) indicates
either an ignition or mechanical problem.
Any fuel injector that significantly (more than 10 kPa) requires service.
Step
| Action
| Value(s)
| Yes
| No
|
1
| Was the
Powertrain On-Board Diagnostic (OBD) System Check performed?
| --
|
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)
or
Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 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.
- Install the fuel pressure gauge.
- Energize the fuel pump using the scan tool.
- Place the bleed hose of the fuel pressure gauge into an approved
gasoline container.
- Bleed the air out of the fuel pressure gauge.
- Using a scan tool pressurize the fuel system.
- Wait for the fuel pressure to build.
Important: The fuel pump will run for approximately 2 seconds. Repeat Step
5 as necessary in order to achieve the highest possible fuel pressure.
- Observe the reading on the fuel pressure gauge.
Is the fuel pressure within the specified limits?
| 333-376 kPa (48-55 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
|
- Connect the J 39021
fuel injector tester to a fuel injector.
- Set the amperage supply selector switch on the fuel injector tester
to the Balance Test 0.5-2.5 amp position.
- Turn the fuel pump ON then OFF in order to pressurize the fuel
system.
- Record the fuel pressure indicated by the fuel pressure gauge
after the fuel pressure stabilizes. This is the 1st 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 gauge
after the fuel pressure gauge needle has stopped moving. This is the 2nd pressure
reading.
- Repeat Steps 1 through 6 for each fuel injector.
- Subtract the 2nd pressure reading from the 1st 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 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.
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
|
9
| Replace the faulty fuel injector(s). Refer to
Fuel Injector Replacement
.
Is the action complete?
| --
| System OK
| --
|
