Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F). Oldsmobile Shelby Series 1 1999

For 1990-2009 cars

Table 1: | Fuel Inj Coil Test - ECT Outside 10-35 Degrees C

### Circuit Description

Refer to Engine Controls Schematics for an electrical diagram of this circuit.

The injector coil test is performed to diagnose a faulty fuel injector. The injector coil test makes use of the J 39021-380 fuel injector test. The tester is used to supply current to each fuel injector. This allows injector resistance measurement by using a DMM to measure voltage drop.

### Diagnostic Aids

Low voltage indicates a high resistance at an injector coil.

### Test Description

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), perform the Fuel Injector Coil Test - ECT Between 10-35°C.

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 or 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 more than 0.7 volt is considered faulty and must be replaced. A fuel injector with a recorded voltage above 9.5 volts is also considered faulty and must be replaced.

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 | 7.0 | 0.1 | P
8 | 7.1 | 0.0 | P

#### Fuel Inj Coil Test - ECT Outside 10-35 Degrees C

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.

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 Fuel Pressure Relief .
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 DMM to the fuel injector tester.
7. Set the DMM to the tenths scale (0.0).
8. Connect the fuel injector tester to a fuel injector.

Important: Check the engine coolant temperature again 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.

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 more than the specified value?

0.6 V

Go to Step 4

Go to Fuel Injector Balance Test

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 action complete?

--

Go to Fuel Injector Balance Test

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