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

Choke Breaker System (CB)

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OPERATION



See Figures 1 and 2

Canada

The choke breaker system is used to monitor the automatic choke system. To prevent too rich a mixture when the choke is closed, the choke breaker forces the choke valve open slightly.

USA

This system performs the same function that the previous one does except that it goes one step further and forces the choke valve to open up even further after the engine has warmed up.



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Fig. Fig. 1: Choke breaker system components layout and vacuum diagram-1984-88 22R engine



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Fig. Fig. 2: Choke breaker system components layout and vacuum diagram-2F engine

SERVICE



See Figures 3 and 4

Checking the CB System
CANADA
  1. Start the engine.
  2.  
  3. Disconnect the hose from the choke breaker diaphragm and check that the choke linkage returns to its previous position.
  4.  
  5. Reconnect the hose to the diaphragm and check that the choke linkage is pulled back by the diaphragm.
  6.  

USA
  1. Carefully note the position of the choke breaker linkage rod.
  2.  
  3. Disconnect the vacuum hose between the choke breaker diaphragm and the 3-way connector at the diaphragm side.
  4.  
  5. Start the engine and check that the choke breaker linkage moves from its former position.
  6.  
  7. Reconnect the vacuum hose to the diaphragm. The linkage should move even further than it was.
  8.  
  9. Check the VSV and the TVSV as detailed in the "Evaporative Emission Control" section.
  10.  



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Fig. Fig. 3: When the vacuum hose is pulled from the diaphragm, the choke linkage should move



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Fig. Fig. 4: When the hose is reconnected the linkage should return to its original position

 
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