Test Description

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

1. 4  - Engine coolant temperature must be less than operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
2. 5  - This step checks that fuel pressure is within specified range.
3. 6  - This step checks for a steady fuel pressure reading.
4. 7  - The fuel injectors are flowing properly if pressure drop value for each fuel injector is within 1.5 psi (10.0 kPa) of average pressure drop value. Calculate pressure drop value for each fuel injector by subtracting second pressure reading from first pressure reading. See Fig 1.

Fig 1: Fuel Injector Tester & Balance Test Example

Courtesy of GENERAL MOTORS CORP.