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Home >> Volvo >> 1993 >> 940 Base, 4D Sedan, AW70L >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Air Induction Systems >> Turbochargers >> Check & Adjust Boost Pressure

Check & Adjust Boost Pressure

  1. Connect air pressure gauge in-line between fuel limiter and intake manifold hose. Use a "T" fitting and enough hose so gauge can be carried into passenger compartment.
  2. Ensure engine is at normal operating temperature. On M/T models, drive vehicle in 3rd gear at about 1500 RPM. On A/T models, place selector in position "2".
    CAUTION: To prevent damage to brakes, DO NOT  apply brakes longer than 5 seconds.
  3. Press accelerator pedal to floor. On A/T models, DO NOT  engage kickdown. Increase engine speed to 3000 RPM, and apply brakes while keeping accelerator pedal down to obtain full load.
  4. Observe boost pressure on gauge. Maximum boost pressure should be 7.0-8.0 psi (.49-.56 kg/cm2 ). If boost pressure is incorrect, adjust boost pressure. Go to next step.
    CAUTION: To prevent damage to wastegate actuator, ensure wastegate actuator rod does not turn when adjusting link rod.
  5. Remove seal and clip from wastegate actuator link rod. Turn link rod to adjust boost pressure to 7.5 psi (.52 kg/cm2 ). See Fig 1 .
  6. Turning link rod one turn will change boost pressure about .5 psi (.03 kg/cm2 ). Turning link rod clockwise will increase boost pressure; counterclockwise will decrease boost pressure.
Fig 1: Adjusting Turbo Boost Pressure
G121547Courtesy of VOLVO CARS OF NORTH AMERICA.
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