C-2A ~ Injector Balance

Diagnostic Chart C-2A Injector Balance:

TEST PURPOSE

The injector tester is used to turn each injector on for a precise amount of time. This allows a measured amount of fuel to be sprayed into the intake manifold, thereby reducing the pressure in the fuel rail. All injectors should measure the same amount of fuel pressure drop (± 10 kPa).

TEST DESCRIPTION: Numbers below refer to the numbers on the diagnostic chart.

NOTE: The entire test should not be performed more than once without running the engine to prevent flooding.

1. Connect fuel gauge J-34731 or equivalent to fuel pressure tap. Wrap a shop towel around fitting while connecting gauge to minimize spillage.
Disconnect all injector connectors and connect injector tester J-34730-3 or equivalent to one injector connector. Ignition must be off for 10 seconds to complete ECM shutdown procedure. Fuel pump should run for about 2 seconds after ignition is turned ON. At this point, insert clear tubing attached to vent valve into a suitable container and bleed air from gauge and hose to insure accurate results.

2. Turn ignition OFF for 10 seconds and then ON again to pressurize fuel system. This insures that fuel pressure is exactly the same for each injector tested. Energize tester one time and note pressure drop the instant the gauge needle stops. the pressure may increase for a seconds after the initial pressure drop. This increase should not be considered in the test, because it varies depending on engine temperature.

3. This This example shows how faulty injectors would appear, as compared to good ones. Usually, good injectors will have virtually the same drop. Retest any injector that has a pressure difference more or less than the average of the other injectors. Replace any injector that also fails the re-test.
If the pressure drop of all injectors is within 10 Kpa of this average, the injectors appear to be flowing properly. Reconnect them,
Symptom Related Diagnostic Procedures