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Home >> Toyota >> 1991 >> Supra 7M-GE, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Air Induction Systems >> Intake Air Induction System >> (Non-Turbo)
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Intake Air Induction System: (Non-Turbo)

  1. Check for loose or leaking vacuum connections. Start engine. At idle, the air control valve (on intake chamber) should be in open position. Slowly increase engine speed to 5000 RPM.
  2. Air control valve should close (vacuum applied). If air control valve does not close, check for vacuum signal to air control valve, and use hand-held vacuum pump to check air control valve diaphragm for leaks.
  3. Replace air control valve if diaphragm is bad. If air control valve is okay, check for voltage between ECU terminal VSV1 (Light Green/Black wire) and ground. Remove glove box. Turn ignition on, with engine off.
  4. With ECU connector plugged in, insert digital voltmeter probe from back side of ECU connector. Ensure there are 0.5-2.0 volts between VSV1 and ground. If voltage is not present, check wiring between ECU and air control valve vacuum switching valve.
    NOTE: Air control valve vacuum switching valve is mounted on top of vacuum reservoir (Light Green/Black and Black/Red wires), in left side of engine compartment.
  5. Ensure there are 0.5-2.0 volts between ECU terminals VSV1 and E1 (Brown wire). If voltage is not present, check voltage between ECU and body ground. If power circuit is okay, unplug vacuum switching valve connector.
  6. Ground one terminal and apply 12 volts to other terminal. Air should flow through valve ports. Remove 12-volt source. Air should flow from one port to air filter. Replace valve if defective.
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