Toyota Pick-ups/Land Cruiser/4Runner 1970-1988

Evaporative Emission Control System

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OPERATION



See Figures 1 and 2

To prevent hydrocarbon emissions from entering the atmosphere due to the evaporation of fuel in the tank and carburetor, Toyota Pick-Up trucks are equipped with evaporative emission control (EEC) systems. Between 1970 and 1971 the case storage system was used. Later models use the charcoal canister storage system.

The major components of the case storage system are a vacuum switching valve, a fuel vapor storage case, an air filter, a thermal expansion tank, and a special fuel tank.

When the vehicle is stopped or the engine is running at low speed, the vacuum switching valve is closed; fuel vapor travels only as far as the case where it is stored. At cruising speed the vacuum switching valve opens and the stored vapors are drawn into the intake manifold along with fresh air drawn through the air filter.

The charcoal storage system functions in a similar manner except that the vapors are stored in a canister filled with activated charcoal. The air filter is an integral part of the charcoal canister. This system employs:

  1. A sealed fuel filler cap with a safety valve.
  2.  
  3. An activated charcoal canister with check valves.
  4.  
  5. A vacuum control valve (VCV)-Land Cruiser.
  6.  
  7. A vacuum switching valve (VSV)-carbureted trucks only.
  8.  
  9. A thermostatic vacuum switching valve (TVSV)-1980-82 only.
  10.  
  11. A bi-metal vacuum switching valve (BVSV)-Pick-Ups (3VZ-E only) and 1988 Land Cruiser.
  12.  
  13. An outer vent control valve.
  14.  



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Fig. Fig. 1: The case storage system for evaporation control



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Fig. Fig. 2: Schematic of the charcoal canister vapor storage system

SERVICE



Checking the Filler Cap

See Figures 3 and 4

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



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Fig. Fig. 3: Checking the fuel filler cap-early models



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Fig. Fig. 4: Checking the fuel filler cap-later models

Checking the 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. All Pick-Ups from 1970-78 have one check valve in the line between the fuel tank and the charcoal canister. It is located in the rear area. To check:

  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.  

1970-87 Land Cruisers have one check valve located in the canister.

1979-88 Pick-Ups with a carburetor and 1988 Land Cruisers have two check valves, both are located in the charcoal canister.

1983-88 Pick-Ups with fuel injection have three check valves in the canister.

To check:
  1. Using low pressure compressed air, blow into the tank pipe. The air should flow from the other pipes without resistance.
  2.  
  3. If the air flow is incorrect, the check valve will require replacement
  4.  

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.

Checking the VCV
LAND CRUISER ONLY

See Figures 5 and 6

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



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Fig. Fig. 5: Checking the VCV-Land Cruiser



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Fig. Fig. 6: Checking the VCV-Land Cruiser

Checking the VSV
CARBURETED TRUCKS ONLY

See Figures 7 and 8

  1. Disconnect the VSV electrical connector.
  2.  
  3. Connect the VSV terminals to the battery terminals.
  4.  
  5. Blow into the pipe and check that the valve is open.
  6.  
  7. Disconnect the positive battery terminal.
  8.  
  9. Blow into the pipe and check that the valve is closed.
  10.  
  11. If the valve is not operating properly it will require replacement.
  12.  



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Fig. Fig. 7: Checking that the VSV is open



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Fig. Fig. 8: Checking that the VSV is closed

Checking the TVSV
1980-82 ONLY

See Figures 9 and 10

  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.  



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Fig. Fig. 9: Checking the TVSV with the engine cold



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Fig. Fig. 10: Checking the TVSV with the engine warm

Checking the BVSV
PICK-UP WITH 3VZ-E ENGINE

See Figures 11 and 12

  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°F (54°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.  



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Fig. Fig. 11: When cold--the BVSV should be closed



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Fig. Fig. 12: When hot--the BVSV should be open

LAND CRUISER WITH 2F ENGINE

See Figure 13

  1. Disconnect the vacuum lines at the BVSV.
  2.  
  3. With the engine cold, blow air into the outer connection and check that the valve closes.
  4.  
  5. Start the engine and run it until it reaches normal operating temperature. Blow air into the outer connection and check that the valve opens.
  6.  
  7. If the valve is not operating properly it will require replacement.
  8.  
  9. Replace the vacuum lines.
  10.  



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Fig. Fig. 13: Checking the BVSV-F and 2F engines

LAND CRUISER WITH 3F-E ENGINE

See Figures 14 and 15

  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 bottom connection. The air should come out of the air filter on top of the valve.
  4.  
  5. Heat the water to a temperature above 147°F (64°C) and again blow into the bottom connection. This time, the air should come out of the upper pipe and not the filter.
  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.  



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Fig. Fig. 14: Checking the BVSV when cold-3F-E engines



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Fig. Fig. 15: Checking the BVSV when hot-3F-E engines

Checking the Outer Vent Control Valve
CARBURETED PICK-UP

See Figures 16, 17 and 18

  1. Disconnect the outer vent hose at the carburetor.
  2.  
  3. Blow air into the outer vent pipe and check that the control valve is open.
  4.  
  5. Start the engine.
  6.  
  7. With the engine running at idle, blow air into the outer vent pipe and check that the control valve is closed.
  8.  
  9. Unplug the control valve electrical connector and check the resistance between the positive (+) terminal in the connector and the solenoid body. Resistance should be 63-73- at 68°F (20°C).
  10.  
  11. Replace the outer vent control valve if it fails either test.
  12.  



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Fig. Fig. 16: Checking the outer vent control (engine OFF)-Pick-ups with carburetors



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Fig. Fig. 17: Checking the outer vent control (engine ON)-Pick-ups with carburetors



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Fig. Fig. 18: Checking solenoid resistance-Pick-ups with carburetors

LAND CRUISER WITH 2F ENGINE

See Figures 19 and 20

  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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Fig. Fig. 19: Checking the outer vent control valve (engine OFF)-2F engine



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Fig. Fig. 20: Checking the outer vent control valve (engine ON)-2F engine

 
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