GM Service Manual Online
For 1990-2009 cars only
Table 1: Example
Table 2: Engine Coolant Temperature Between 10°C - 35°C (50°F - 95°F) Test Procedure

Object Number: 17707  Size: MF

Diagnostic Aids

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

Test Description

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

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 NOT Between 10°C-35°C (50°F-95°F), go to Fuel Injector Coil Test Procedure - Engine Coolant Temperature Outside 10°C-35°C (50°F-95°F).

  2. The first second of the voltage displayed by the DVM may be inaccurate due to the initial current surge, therefore, record the lowest voltage displayed by the DVM after the first second of the test. The voltage displayed by the DVM should be within the specified range (refer to the Example). The voltage displayed by the DVM 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.

Engine Coolant Temperature Between 10°C - 35°C (50°F - 95°F) Test Procedure

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°C-35°C (50°F-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: The fuel system must not be pressurized.

  1. Relieve the fuel pressure. Refer to Fuel Pressure Relief
  2. Disconnect the fuel injector electrical connector.
  3. Connect the J 39021 fuel injector tester.
  4. Select the coil test 0.5 AMP position on the fuel injector tester.
  5. Connect the leads from the digital multimeter (DMM) to the fuel injector tester and select the DC voltage tenths scale.
  6. Press the PUSH TO START TEST button on the Fuel Injector Coil/Balance Tester.
  7. Record the lowest voltage after the first second of the test.
  8. Repeat for each fuel injectors.

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

5.7-6.6 volts

Go to Step 4

Go to Fuel Injector Balance Test

4

Replace the faulty fuel injectors.

Refer to Fuel Injector Replacement

Did you complete the replacement?

--

Go to Step 5

--

5

Does any driveabilty condition still exist?

--

Go to Applicable Diagnostic

System OK