Injector Balance Test (2.2L & 3.4L)

NOTE: Allow engine to cool down to avoid irregular reading due to "hot soak" fuel boiling. To prevent flooding, the fuel injector balance test should not be performed more than once without starting and running engine.

NOTE: If injectors are dirty, they should be cleaned using approved injector cleaning procedure before performing fuel injector balance test.

Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing powertrain diagnostic system check, go to next step.
If injector coil test has been performed, go to next step. If injector coil test has not been performed, see appropriate INJECTOR COIL TEST - ECT IS 50-95°F.
If engine coolant temperature is greater than 201°F (94°C), go to next step. If engine coolant temperature is less than 201°F (94°C), go to step 5.
Allow engine to cool to less than 201°F (94°C). After engine cools to less than 201°F (94°C), go to next step.
Install fuel pressure gauge. Using scan tool, energize fuel pump. Place fuel pressure gauge bleed hose into container. Bleed air out of fuel pressure gauge. Using scan tool, energize fuel pump again. Wait for fuel pressure to build. Observe fuel pressure. If fuel pressure reading is 41-47 psi (2.9-3.3 kg/cm² ), go to next step. If fuel pressure reading is not within specification, perform fuel system diagnosis. See appropriate BASIC DIAGNOSTIC PROCEDURES article.
Turn fuel pump off. Observe fuel pressure gauge. If fuel pressure remains constant, go to next step. If fuel system does not remain constant, perform fuel system diagnosis. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

NOTE: Perform step 7 on each injector.

Disconnect fuel injectors harness connector. Using appropriate fuel injector adapter, connect Fuel Injector Tester (J-39021) to fuel injector. Connect fuel injector tester power leads to appropriate battery terminals. Set amperage supply selector switch on fuel injector tester to Balance Test 0.5-2.5-amp position. Turn ignition on, and then off to pressurize system. Record fuel pressure reading after fuel pressure stabilizes (first reading). Energize injector by depressing PUSH TO START TEST button on injector tester and hold until fuel pressure gauge stabilizes. Record fuel pressure reading (second reading). Subtract first reading from second reading (this result is pressure drop value). Repeat procedure for each injector. Add pressure drop value for each injector together and divide total by total number of injectors. If any injector's drop value is greater or less than average drop value by 1.5 psi, replace faulty injector(s) as necessary. If no injector's drop value is greater or less than average drop value by 1.5 psi, repair by symptom. See appropriate TROUBLE SHOOTING - NO CODES article.