Chart C-2A Injector Balance Test

Chart C-2A - Injector Balance Test:

CHART C-2A INJECTOR BALANCE TEST

The injector tester is a timer used to turn each injector on for precisely 0.5 seconds. This time allows a measured amount of fuel to be sprayed into the intake manifold thereby reducing the pressure in the fuel rail. All injectors in the engine should measure about the same fuel drop.


STEP 1

Connect fuel gage J-347301 or equivalent to fuel pressure tap. Wrap a shop towel around the fitting while connecting gage to avoid fuel spillage.

Disconnect harness connectors at all injectors, and connect injector tester harness to one injector. Follow manufacturers instructions for use of adaptor harness. Ignition must be off at least 10 seconds to complete Engine Control Module (ECM) shutdown cycle. Fuel pump should run 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 gage and hose to insure accurate gage operation.


STEP 2

Turn ignition off for 10 seconds and then on again to get fuel pressure to its maximum. This insures that fuel pressure is precisely the same for each injector test. Energize tester one time and note pressure drop the instant the gage needle stops. The pressure may increase for a few seconds after the initial pressure drop. This increase should not be considered in the test, as it will vary depending on temperature.


STEP 3

This example show how faulty injectors would appear, as compared to good ones. Retest any injector that appears to be faulty and replace any injector that has a pressure difference of 10 kPa, either more or less that the other injectors on the engine. If all injectors test within a 10 kPa range in pressure drop, reconnect injectors and review "Diagnose by Symptoms".