Toyota Tercel 1984-1994 Repair Guide

Air Suction

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OPERATION



Used on 3A-C and 3E engines.

The air suction (AS) system brings fresh, filtered air into the exhaust ports to reduce HC and CO emissions. On some applications, it also supplies the air necessary for the oxidizing reaction in the catalytic converter.

TESTING



Air Suction Valve

See Figures 1 through 5

WITHOUT VACUUM DIAPHRAGM
  1. Blow hard through the outlet side of the AS valve, there should be no air flow.
  2.  
  3. There should be flow through the outlet pipe when sucked.
  4.  

WITH VACUUM DIAPHRAGM
  1. Apply vacuum to the AS valve diaphragm.
  2.  
  3. Blow hard through the outlet side of the AS valve, there should be no air flow.
  4.  
  5. There should be flow through the outlet pipe when sucked.
  6.  
  7. Release the vacuum. Check that very little air flows when the outlet pipe is sucked.
  8.  



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Fig. Fig. 1: Air suction valves found on 3A-C federal engines



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Fig. Fig. 2: Air suction valve found on 3A-C California and most 3A-C Canada engines



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Fig. Fig. 3: Air suction valve found on most manual transaxle wagons with 3A-C Canada engines



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Fig. Fig. 4: Air suction valve found on 3E federal and Canada engines



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Fig. Fig. 5: Air suction valve found on 3E California engines

Vacuum Transmitting Valve

See Figure 6

  1. Check that air flows without resistance from B to A .
  2.  
  3. Check that air flows with difficulty from A to B .
  4.  
  5. If a problem is found, replace the vacuum delay valve.
  6.  

If replacing the vacuum transmitting valve, side A should face towards the AS valve.

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Fig. Fig. 6: Vacuum transmitting valve airflow

 
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