GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC K Sierra - 4WD 🢒 Engine 🢒 Engine Controls - 4.8L, 5.3L, and 6.0L 🢒 Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F)
Table 1: Example

Object Number: 17707 Size: MF

Test Description

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. The engine coolant temperature affects the ability of the fuel injector tester to detect a faulty fuel injector. If the engine coolant temperature is between 10°C-35°C (50°F-95°F), go to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F)

  2. The first second of the voltage displayed by the DMM may be inaccurate due to the initial current surge. Therefore, record the lowest voltage displayed by the DMM after the first second of the test. The voltage displayed by the DMM may increase throughout the test as the fuel injector windings warm and the resistance of the fuel injector windings changes. An erratic voltage reading (large fluctuations in voltage that do not stabilize) indicates an intermittent connection within the fuel injector. From the voltages recorded, identify the highest voltage, excluding any voltages above 9.5 volts. Subtract each voltage that is not above 9.5 volts from the highest voltage. Record each subtracted value (refer to the Example). The subtracted value for any fuel injector must not exceed 0.6 volt. A fuel injector with a subtracted value that is greater than 0.6 volt is faulty. Replace the fuel injector. A fuel injector with a recorded voltage above 9.5 volts is also faulty. Replace the fuel injector.

Example

Highest Voltage Reading

Acceptable Subtracted Value Above/Below

10°C-35°C (50°F-95°F)

7.1 V

0.6 V

Injector Number

Voltage

Subtracted Value

Pass/Fail

1

9.8

--

F

2

6.6

0.5

P

3

6.9

0.2

P

4

5.8

1.3

F

5

7.0

0.1

P

6

7.1

0.0

P

7

9.6

--

F

8

6.0

1.1

F

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2
  1. Connect the scan tool.
  2. Check the engine coolant temperature.

Is the engine coolant temperature outside the specified limits?

10°C-35°C (50°F-95°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
  1. Turn the ignition OFF.

    2. Notice: In order to prevent flooding of a single cylinder and possible engine damage, relieve the fuel pressure before performing the fuel injector coil test procedure.

  2. Relieve the fuel pressure. Refer to the Fuel Pressure Relief Procedure .
  3. Access the fuel injector electrical connectors as required.
  4. Connect the J 39021 fuel injector tester to B+ and ground.
  5. Set the amperage supply selector switch on the fuel injector tester to the Coil Test 0.5 amp position.
  6. Connect the leads from the J 39200 Digital Multi Meter (DMM) to the fuel injector tester. Refer to the illustration associated with the test description.
  7. Set the DMM to the tenths scale (0.0).
  8. Connect the fuel injector tester to a fuel injector using the J 39021-380 injector test adapter.

    9. Important: Check the engine coolant temperature again in order to ensure that the correct chart is being used.

  9. Press the Push to Start Test button on the fuel injector tester.
  10. Observe the voltage reading on the DMM.

    11. Important:: The voltage reading may rise during the test.

  11. Record the lowest voltage observed after the first second of the test.
  12. Repeat steps 8 through 11 for each fuel injector.
  13. Identify the highest voltage reading recorded other than those above 9.5 volts.
  14. Subtract any other voltage reading recorded from the highest voltage reading recorded.
  15. Repeat step 14 for all the remaining fuel injectors.

Is any value that resulted from subtraction greater than the specified value?

0.6V

Go to Step 4

Go to Fuel Injector Balance Test with Tech 2 or Fuel Injector Balance Test with Special Tool

4

Replace any fuel injector that had any of the following:

    • A subtracted value exceeding 0.6 volts.
    • An initial reading above 9.5 volts.
    • An erratic reading.

Refer to Fuel Injector Replacement .

Is the replacement complete?

--

Go to Fuel Injector Balance Test with Tech 2 or Fuel Injector Balance Test with Special Tool

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