Toyota Pick-ups/Land Cruiser/4Runner 1989-1996

Air Suction System

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OPERATION



See Figures 1, 2 and 3

This system only applies to the 22R-E and 3VZ-E engines.

This system is used to introduce extra fresh air into the exhaust ports to accelerate oxidation and after-burn of exhaust gases. This helps reduce HC and CO emissions. The system uses vacuum generated by the exhaust pulses in the manifold to control the entry of fresh air into the system.



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Fig. Fig. 1: Air Suction system components and locations



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Fig. Fig. 2: System schematic and air flow



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Fig. Fig. 3: Air Suction system operating conditions

TESTING



System Testing
  1. With the engine cold, but running at idle, disconnect the air suction hose from the air cleaner.
  2.  
  3. A bubbling or gurgling noise should be heard from the hose (22R-E) or pipe (3VZ-E).
  4.  

  1. Warm the engine to normal operating temperature.
  2.  
  3. Again listen for the noise; it should not be heard with the engine warm.
  4.  
  5. Race the engine above 2000 rpm.
  6.  
  7. On 3VZ-E, the noise should reappear within 2-6 seconds.
  8.  
  9. On 22R-E, quickly close the throttle from 2000 rpm. The noise heard in the hose should stop momentarily.
  10.  

Reed Valve

The reed valve should be checked with vacuum applied to the diaphragm. With vacuum applied, air should pass through the valve. With vacuum removed, the valve should not conduct air.

Vacuum Solenoid Valve (VSV)
  1. Perform these tests with the ignition OFF . Unplug the wiring connector and vacuum hoses from the VSV.
  2.  
  3. Use jumper wires to connect the terminals of the valve to the battery terminals.
  4.  
  5. Blow into the port closest to the body of the valve. Air should come out the other port
  6.  
  7. Disconnect the jumpers from the battery. Again blow into the port nearest the body of the valve; air should not come out the other port and should come out of the air filter on the side of the valve.
  8.  
  9. Use an ohmmeter to check for a short in the valve. Place one probe against the body of the valve and check each terminal for continuity. No continuity should exist between either terminal and the body of the valve.
  10.  
  11. Measure resistance across the pins of the terminal. With the valve at 68°F (20°C), resistance should be 30-50 ohms. Resistance will vary with temperature; use good judgment when interpreting test results.
  12.  
  13. Reinstall the valve if it was removed. Connect the hoses and wire harness.
  14.  

Check Valve

The check valve is a simple one-way valve to prevent vacuum loss within the system. The colored side is always the input side, so blowing into the colored side will allow air to pass. Blow (gently) into the black side; no air should pass. If the valve was removed for testing, make certain it is reinstalled correctly.

 
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