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HOMESERVICE MANUALSCHEVROLET2008OPTRA5 LT, STANDARDREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEMENGINE CONTROLS AND FUEL - 1.6LDIAGNOSTIC INFORMATION AND PROCEDURESINTAKE MANIFOLD TUNING VALVE DIAGNOSISCIRCUIT/SYSTEM TESTING
2008 Chevrolet Optra5 LT, Standard

Circuit/System Testing

2008 Chevrolet Optra5 LT, StandardSECTION Circuit/System Testing
  1. Verify none of the following conditions exist:
    • Disconnected, restricted, or damaged vacuum hoses
    • Disconnected or damaged components
    • Binding vacuum actuator linkage
    • Linkage that is interfering with hoses, wiring, or any other components
    • Internally binding IMT valve-Refer to Intake Manifold Replacement .
  2. Ignition OFF, disconnect the vacuum supply hose at the vacuum reservoir.
  3. Connect a J 23738-A  to the supply hose of the vacuum reservoir.
  4. Engine running, test for 33 kPa (10 Hg)  of vacuum.
    • If less than the specified range, test for a leak or restriction in the supply hose.
  5. Ignition OFF, connect a J 23738-A  to the supply port of the vacuum reservoir.
  6. Disconnect the vacuum outlet hose at the vacuum reservoir.
  7. Plug the vacuum outlet port of the vacuum reservoir, while applying vacuum to the vacuum reservoir.
    • If the vacuum does not hold, replace the vacuum reservoir.
  8. Ignition OFF, connect the vacuum hoses to the vacuum reservoir.
  9. Disconnect the supply hose at the IMT valve solenoid.
  10. Connect a J 23738-A  to the vacuum supply hose at the IMT valve solenoid.
  11. Engine running, test for 33 kPa (10 Hg)  of vacuum.
    • If less than 3the specified range, test for a leak or restriction in the supply hose.
  12. Ignition OFF, connect the supply hose to the IMT valve solenoid.
  13. Disconnect the outlet hose at the IMT valve solenoid.
  14. Connect a J 23738-A  to the outlet hose at the IMT valve solenoid.
  15. Engine running, test for 33 kPa (10 Hg)  of vacuum.
    • If less than the specified range, replace the IMT valve solenoid.
  16. Ignition OFF, connect the outlet hose to the IMT valve solenoid.
  17. Disconnect the supply hose at the vacuum actuator.
  18. Connect a J 23738-A  to the outlet hose at the IMT valve solenoid.
  19. Engine running, test for 33 kPa (10 Hg)  of vacuum.
    • If less than the specified range, test for a leak or restriction in the supply hose.
  • If greater than the specified range, replace the vacuum actuator.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.