LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Pontiac >> 2003 >> Aztek AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel Systems >> Fuel Injector Balance Test With Tech 2 >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Perform FUEL INJECTOR COIL TEST  . After performing Fuel Injector Coil Test, go to next step.
    3. NOTE: DO NOT perform this test if ECT is above 201°F (94°C).
  3. Observe ECT parameter with scan tool. Does scan tool indicate ECT parameter is less than 201°F (94°C)? If yes, go to next step. If no, allow engine to cool before proceeding.
    4. NOTE: Verify there is adequate fuel in fuel tank before proceeding with this step. Fuel pump may need to be commanded ON a few times, in order to obtain highest possible fuel pressure reading. DO NOT allow engine to start.
  4. Turn ignition off. Turn off all accessories. Install fuel pressure gauge. Turn ignition on, with engine off. Command fuel pump ON with scan tool. Observe fuel pressure gauge, with fuel pump commanded ON. Is fuel pressure within 52-59 psi (358-405 kPa)? If yes, go to next step. If no, go to FUEL SYSTEM PRESSURE TEST under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article.
    5. NOTE: Fuel pressure may vary slightly when fuel pump stops operating. After fuel pump stops operating, fuel pressure should stabilize and remain constant.
  5. Monitor fuel pressure gauge for one minute. Does fuel pressure decrease by more than 5 psi (34 kPa)? If yes, go to FUEL SYSTEM PRESSURE TEST under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.4L AZTEK & RENDEZVOUS article. If no, go to next step.
    6. NOTE: Fuel pressure may rise after fuel injector stops pulsing. Record fuel pressure value immediately after fuel injector stops pulsing. DO NOT record higher fuel pressure value.
  6. With scan tool, select Fuel Injector Balance Test function, within Special Functions menu. Select an injector to be tested. Press Enter. This will prime fuel system. Record fuel pressure indicated by fuel pressure gauge after fuel pressure stabilizes. This is first pressure reading. Energize fuel injector by depressing Pulse Injector button on scan tool. This will energize injector and decrease fuel pressure. Record fuel pressure indicated by fuel pressure gauge after fuel injector has stopped pulsing. This is second pressure reading. Press Enter again to bring you back to Select Injector screen. Repeat this step for each fuel injector. Subtract second pressure reading from first pressure reading for one fuel injector. Result is pressure drop value. Obtain a pressure drop value for each fuel injector. Add all individual pressure drop values. This is total pressure drop. Divide total pressure drop by number of fuel injectors. This is average pressure drop. Does any fuel injector have a pressure drop value that is more than average pressure drop or less than average pressure drop by 1.5 psi (10 kPa)? If yes, go to next step. If no, go to SYMPTOMS in TROUBLE SHOOTING - NO CODES - 3.4L AZTEK & RENDEZVOUS article.
  7. Replace affected fuel injectors. After repairs, go to next step.
  8. Operate system in order to verify repair. Does a driveability condition still exist? If yes, go to SYMPTOMS in TROUBLE SHOOTING - NO CODES - 3.4L AZTEK & RENDEZVOUS article. If no, system is okay.
scientia non olet · About LEMON Manuals