Toyota Celica/Supra 1971-1985 Repair Guide

Evaporative Emissions Controls

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In order to prevent HC emissions from entering the atmosphere, all Celicas and Supras utilize an evaporation control system. This system employs:



A sealed fuel filler cap with a safety valve.
 
An activated charcoal canister with check valves.
 
A Vacuum Control Valve (VCV)-Supra to 1982
 
A Vacuum Switching Valve (VSV)-Celica and 5M-GE Supra
 
A Thermostatic Vacuum Switching Valve (TVSV)-1980-82 Celica
 
A Bi-metal Vacuum Switching Valve (BVSV)-Supra and 1982-85 Celica
 
An outer vent control valve-California Celicas
 

COMPONENT TESTING



Filler Cap

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: The fuel filler cap (gas cap) has a safety valve built in

Check that the filler cap seals effectively. Remove the filler cap and pull the safety valve outward to check for smooth operation. Replace the filler cap if the seal is defective or if it is not operating properly.

Charcoal Canister and Check Valves

Remove the charcoal canister from the engine compartment and visually inspect it for cracks or other damage. Check for stuck check valves.

1971-78 MODELS

All models from 1971-78 have one check valve in the line between the fuel tank and the charcoal canister. It is located in the trunk.

  1. Remove the check valve from the line.
  2.  

Mark which end goes toward the fuel tank and which end goes toward the charcoal canister.

  1. Blow into the fuel tank end. A slight resistance should be felt at first.
  2.  
  3. Blow through the other end. No resistance should be felt at all.
  4.  
  5. If your results differ from those above, the check valve will require replacement.
  6.  

1979-85 MODELS
  1. The 1979-82 models have two check valves; both are located in the charcoal canister. The 1983-85 fuel injected models have three check valves in the canister.
  2.  
  3. Using low pressure compressed air, blow into the tank pipe. The air should flow from the other pipes without resistance.
  4.  
  5. If the air flow is incorrect, the check valve will require replacement
  6.  

Before installing the canister, clean the filter. Blow compressed air into the purge pipe while keeping the other blocked with your fingers.

Do not attempt to wash the charcoal canister. While cleaning the canister, under no circumstances should any activated charcoal be removed.

Vacuum Control Valve (VCV)
SUPRA

See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: When applying vacuum to pipe S on the VCV, it should let air pass through the ports shown

  1. Locate the VCV by the intake air chamber. Label and remove all the vacuum lines.
  2.  
  3. Apply vacuum to pipe S , blow into Y and check that the valve is open.
  4.  
  5. Stop the vacuum and blow into Y again and check that the valve is closed.
  6.  
  7. If the valve is not operating properly, it will require replacement.
  8.  

Vacuum Switching Valve (VSV)

See Figures 3 and 4



Click image to see an enlarged view

Fig. Fig. 3: Apply battery power to the VSV terminals as illustrated



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Fig. Fig. 4: Remove the battery power, then check that air passes through pipe G

  1. Disconnect the VSV electrical harness.
  2.  
  3. Connect the VSV terminals to the battery terminals.
  4.  
  5. Blow into the pipe E and check that air comes out of pipe F .
  6.  
  7. Disconnect the battery terminals to the unit as shown in the illustration.
  8.  
  9. Blow into the pipe E and check that air comes out of pipe G .
  10.  
  11. If the valve is not operating properly it will require replacement.
  12.  

Thermal Vacuum Switching Valve (TVSV)
1980-82 CELICA

See Figures 5 and 6



Click image to see an enlarged view

Fig. Fig. 5: Blow air into the middle pipe, then check that air comes out of the top pipe



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Fig. Fig. 6: With the engine at operating temperature, air should pass through the bottom pipe

  1. Locate the TVSV on the intake manifold and remove all vacuum lines.
  2.  
  3. Blow into the middle pipe and check that the air comes out of the top pipe.
  4.  
  5. Warm up the engine until it reaches normal operating temperature and then blow into the middle pipe again. The air should come out of the bottom pipe.
  6.  
  7. If the valve is not operating properly it will require replacement.
  8.  

Bimetal Vacuum Switching Valve (BVSV)
SUPRA AND 1982-83 CELICA

See Figures 7 and 8



Click image to see an enlarged view

Fig. Fig. 7: When the valve is below its calibrated temperature, air should not pass



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Fig. Fig. 8: As the temperature is increased past the calibration point, air should pass

  1. Drain the engine coolant and remove the BVSV from the water outlet on the engine block.
  2.  
  3. Place the end of the BVSV in cool water and blow into the top connection. The valve should be closed.
  4.  
  5. Heat the water to a temperature above 129°deg;F (54°deg;C) and again blow into the top connection. This time, the valve should be open.
  6.  
  7. If the valve is not operating properly it will require replacement.
  8.  
  9. Apply liquid sealer to the threads and reinstall the BVSV.
  10.  
  11. Refill the engine with coolant.
  12.  

Outer Vent Control Valve
CALIFORNIA CELICAS

See Figures 9 and 10



Click image to see an enlarged view

Fig. Fig. 9: With the engine OFF, blow air into the outer vent pipe. Make sure it passes air



Click image to see an enlarged view

Fig. Fig. 10: With the ignition switch ON, blow air into the outer vent pipe. Make sure the valve is closed

  1. Remove the vacuum lines from the valve.
  2.  
  3. With the ignition switch OFF , blow into the top pipe on the valve. The valve should be open.
  4.  
  5. With the ignition switch ON , blow into the top pipe again, the valve should now be closed.
  6.  
  7. If the valve is not working properly, first check the fuse and all the wiring connections. If they are all correct, the valve will require replacement.
  8.  

 
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