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Home >> Chevrolet >> 2002 >> Prizm Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel System >> Fuel Injector Balance Test >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article. After performing diagnostic system check, go to next step.
  2. Perform fuel injector coil test. See FUEL INJECTOR COIL TEST - ENGINE COOLANT TEMPERATURE IS 50-95°F  . After performing fuel injector coil test, go to next step.
  3. Is the engine coolant temperature more than 201°F (94°C)? If yes, go to next step. If no, go to step  5 .
  4. Allow engine to cool to less than 201°F (94°C). After engine coolant temperature is less than 201°F (94°C), go to next step.
  5. Install Fuel Pressure Gauge (J-34730-1A). Using scan tool, energize fuel pump. Place fuel pressure gauge bleed hose into a container and bleed out air. Observe fuel pressure gauge. Is the fuel pressure within 44-50 psi? If yes, go to next step. If no, see FUEL SYSTEM PRESSURE TEST under BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
  6. Turn fuel pump off. Does the fuel pressure remain constant? If yes, go to next step. If no, see FUEL SYSTEM PRESSURE TEST under BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
  7. Use 2 jumper wires from the Connector Test Adapter Kit (J 35616-A) in order to connect the fuel injector to the Fuel Injector Tester (J 39021) test leads. Connect the J 39021 to battery voltage and to ground. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position. Energize the fuel pump by using the scan tool. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure stabilizes. This is the 1st pressure reading. Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure gauge needle has stopped moving. This is the 2nd pressure reading. Repeat procedure for each fuel injector. Subtract the 2nd pressure reading from the 1st pressure reading for one fuel injector. The result is the pressure drop value. Obtain a pressure drop value for each fuel injector. Add all of the individual pressure drop values. This is the total pressure drop. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop. Does any fuel injector have a pressure drop value that is higher or lower than the average pressure drop by 1.5 psi? If yes, go to next step. If no, see appropriate TROUBLE SHOOTING - NO CODES article.
    8. NOTE: Do not repeat any portion of this test before running the engine in order to prevent the engine from flooding.
  8. Repeat step  7 for injectors that do not meet specification. Does any fuel injector still have a pressure drop value that is either higher or lower than the average pressure drop by 1.5 psi? If yes, go to next step. If no, see appropriate TROUBLE SHOOTING - NO CODES article.
  9. Replace faulty fuel injector(s). After repairs, go to next step.
  10. Does an engine performance concern still exist? If yes, see appropriate TROUBLE SHOOTING - NO CODES article. If no, system is okay.
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