Chart C-2A Injector Balance Test - PFI

Fig. 006 - Chart C-2A - Injector Balance Test:

CHART C-2A

INJECTOR BALANCE TEST

The injector tester is a timer used to turn each injector for precisely .5 seconds. This time allows a measured amount of 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 pressure drop.

STEP 1
Connect fuel gage to fuel pressure tap. Wrap a shop towel around fitting while connecting gage to avoid fuel spillage.
Disconnect harness connectors at all injectors, and connect injector tester to one injector. On Turbo equipped engines, use adaptor harness furnished with injector tester to energize injectors that are not accessible. Follow manufacturers instructions for use of adaptor harness. Ignition must be off at least 10 seconds to complete 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 shows 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 10kPa, either more or less than the other injectors on the engine. If all injectors test within a 20 kPa range in pressure drop, reconnect injectors and review Symptoms.