Test Description

The following list gives a description for appropriate step numbers in diagnostic procedure.

1. 2  - Engine coolant temperature affects the ability of the fuel injector tester to detect a faulty fuel injector.
2. 3  - The first second of voltage displayed by DVOM may be inaccurate due to initial current surge. Therefore, record lowest voltage displayed by DVOM after first second of test. Voltage displayed by DVOM should be 4.5-7.0 volts. See Fig 1. Voltage displayed by DVOM may increase throughout test as fuel injector windings warm and resistance of fuel injector windings changes. An erratic voltage reading indicates an intermittent connection within fuel injector.

Fig 1: Fuel Injector Tester & Injector Coil Test Example (2.5L - ECT Is 50-95°F)

Courtesy of GENERAL MOTORS CORP.