Fuel Injector Balance Test: Description
The numbers below refer to the step numbers in the diagnostic procedures.
- 4
The Engine Coolant Temperature (ECT) must be below the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling. - 5
The fuel pressure should be within the specified range. If the fuel pressure is not within the specified range, see FUEL SYSTEM DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article. - 6
The fuel pressure should reach a steady value. If the fuel pressure does not reach a steady value, see FUEL SYSTEM DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article. - 7
The fuel injectors are flowing properly if the pressure drop value for each fuel injector is within 1.5 psi of the average pressure drop value. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading. Refer to Fuel Injector Balance Example. See FUEL INJECTOR BALANCE EXAMPLE table.
FUEL INJECTOR BALANCE EXAMPLE
| Cylinder No. | First Reading | Second Reading | Amount Of Drop | Average Range: 35-38 psi |
|---|---|---|---|---|
| 1 | 47 psi | 36 psi | 11 psi | Good |
| 2 | 47 psi | 34 psi | 13 psi | Faulty, Too Much Drop |
| 3 | 47 psi | 37 psi | 10 psi | Good |
| 4 | 47 psi | 39 psi | 8 psi | Faulty, Too Little Drop |