GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 Century (China) 🢒 Engine 🢒 Engine Controls - 2.5L (LB8) and 3.0L (L46) 🢒 Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F)
Table 1: Example
Table 2: Fuel Injector Coil Test -- ECT Between 10°C-35°C (50°F-95°F)

Circuit Description

The Powertrain Control Module (PCM) controls the fuel injector control circuit using a multi function driver (MFD). Power is supplied from the injector fuse to the injector and is grounded by the PCM. The MFD controls the injector ground, allowing fuel flow to pulse.

Diagnostic Aids

Test the engine fuel injection harness for the following conditions:

    • Poor Terminal Connection.
        Inspect the harness connectors for:
       - Backed out terminals
       - Improper mating
       - Broken locks
       - Improperly formed or damaged terminals
       - Faulty terminal to wire connection
    • Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
    • Damaged harness.
        Inspect the wiring harness for damage. Refer to Wiring Repairs in Wiring Systems.

Test Description

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

  1. The engine coolant temperature (ECT) affects the resistance in the fuel injector and the ability of the fuel injector tester to detect a faulty fuel injector. If the ECT is between the specified value, refer to Fuel Injection Coil Test--ECT Between 10°C-35°C.

    2.

  2. The first second of the voltage displayed by the digital multimeter (DMM) may be inaccurate due to the initial current surge. Therefore, record the lowest voltage displayed by the DMM after the first second. The voltage displayed by the DMM should be within the specified value. Refer to the example. The voltage displayed by the DMM may increase throughout the test as the fuel injectors windings warm and the resistance changes. An erratic reading indicates an intermittent connection within the fuel injector and the fuel injector must be replaced. A fuel injector outside the specified value is considered faulty and must be replaced.

Example

Resistance Ohms

Voltage Specification at 10°C-35°C

(50°F-95°F)

11.4-12.6

5.7-6.6

Fuel Injector Number

Voltage Reading

Pass/Fail

1

6.3

P

2

5.9

P

3

6.2

P

4

6.1

P

5

4.8

F

6

6.0

P

Fuel Injector Coil Test -- ECT Between 10°C-35°C (50°F-95°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. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, monitor the ECT parameter.

Does the temperature measure between the specified value?

10°-35°C (50°95°F)

Go to Step  3

Go to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F)

3

    Important : Fuel system must not be pressurized. Refer to Fuel Pressure Relief .

  1. Install the J 39021 fuel injector coil/balance tester, J 39021 - 210 injector selector switch box and the J 39021-410 fuel injection coil test harness.
  2. Select the coil test 0.5 AMP position on the fuel injector tester.
  3. Connect the leads of the DMM to the fuel injector tester and select the DC voltage tenths scale.
  4. Select an injector on the J 39021 - 210 injector selector switch box.
  5. Press the PUSH TO START TEST button on the fuel injector coil/balance tester.
  6. Record the lowest reading after the first second.
  7. Repeat for each fuel injector.

Does any fuel injector have an erratic reading or a reading outside the specified value?

5.7-6.6 volts

Go to Step  4

Go to Fuel Injector Balance Test

4
  1. Remove the upper Intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical.
  2. Test the fuel injection harness between the 16-way connector and the injector for the following conditions:
    3. • An open or short to ground in the fuel injection harness.
    • Poor terminal connections at the fuel injector.

Did you find and correct the condition?

--

Go to Step 6

Go to Step 5

5

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

Did you complete the replacement?

--

Go to Step 6

--

6

Does any driveabilty condition still exist?

--

Go to the applicable DTC table

System OK