Chrysler Caravan/Voyager/Town n Country 1984-1995

Exhaust Emission Controls

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HEATED INLET AIR SYSTEM



All 2.2L and 2.5L engines are equipped with a vacuum device located in the air cleaner air intake. A small door is operated by a vacuum diaphragm and a thermostatic spring. When the outside air temperature is below a specified level, the door will block off air entering from outside the air cleaner snorkel and allow heated air, channeled from the exhaust manifold area, to enter the air cleaner assembly. With the engine warmed up and running the thermostatic spring allows the heat control door to draw outside air through the air cleaner snorkel.

On later models the air temperature in the air intake is monitored by a temperature sensor in the intake housing.

SYSTEM INSPECTION



A malfunction in the heated air system will affect driveability and the emissions output of the vehicle.

2.2L Engines


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Fig. Fig. 1: Heated air intake system-2.2L engines



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Fig. Fig. 2: Testing the vacuum diaphragm-2.2L engines



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Fig. Fig. 3: Testing the heated air inlet diaphragm

  1. Verify all vacuum hoses and the flexible heat pipe between the air cleaner and heat stove are properly attached and in good condition.
  2.  
  3. On a cold engine with an ambient temperature less than 65°F (19°C) the heat door valve plate in the snorkel should be in the up position (Heat On).
  4.  
  5. With the engine running at normal operating temperature, the heat door should be in the down position (Heat Off).
  6.  
  7. If the heat door valve plate does not respond to hot and cold temperatures, the door diaphragm or the sensor may need replacing.
  8.  
  9. To test the diaphragm, remove the air cleaner from the engine and allow it to cool down to 65°F (19°C).
  10.  
  11. Connect a hand-operated vacuum pump to the vacuum diaphragm and apply 20 in. Hg (68 kPa) of vacuum. The diaphragm should not leak down more than 10 in. Hg (34 kPa) in 5 minutes. The control door should not lift from the bottom of the snorkel at less than 2 in. Hg (7 kPa) and be in the full up position with no more than 4 in. Hg (14 kPa) of vacuum. If the vacuum test proves the diaphragm defective, replace the air cleaner.
  12.  
  13. If the vacuum test shows the diaphragm in proper working condition, replace the sensor.
  14.  
  15. Label the vacuum hoses at the sensor to aid during reassembly. Disconnect the vacuum hoses, remove the retaining clips with a prytool and discard. Remove the sensor and mounting gasket.
  16.  
  17. Position the new gasket on the sensor and install sensor. Support the sensor on the outer diameter, and install the retaining clips.
  18.  
  19. Reconnect vacuum hoses.
  20.  

2.5L Engines

See Figure 4



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Fig. Fig. 4: Heated air intake system-2.5L engines

  1. Verify all vacuum hoses and the flexible heat pipe between the air cleaner and heat stove are properly attached and in good condition.
  2.  
  3. On a cold engine with an ambient temperature less than 115°F (46°C) the heat door valve plate in the snorkel should be in the up position (Heat On).
  4.  
  5. With the engine running at normal operating temperature, the heat door should be in the down position (Heat Off).
  6.  
  7. If the heat door valve plate does not respond to hot and cold temperatures, the door diaphragm or the sensor may need replacing.
  8.  
  9. To test the diaphragm, remove the air cleaner from the engine and allow it to cool down to 115°F (46°C).
  10.  
  11. Connect a hand-operated vacuum pump to the sensor and apply 20 in. Hg (68 kPa) of vacuum. The door valve should be in the up position (Heat On).
  12.  
  13. If the door does not raise to "Heat On" position, test the vacuum diaphragm for proper operation.
  14.  
  15. Apply 20 in. Hg (68 kPa) of vacuum with a hand operated vacuum pump to the vacuum diaphragm. The diaphragm should not leak down more than 10 in. Hg (34 kPa) in 5 minutes. The control door should not lift from the bottom of the snorkel at less than 2 in. Hg (7 kPa) of vacuum and be in the full up position with no more than 4 in. Hg (14 kPa) of vacuum. If the vacuum test proves the diaphragm defective, replace the air cleaner.
  16.  
  17. If the vacuum test shows the diaphragm in proper working condition, replace the sensor.
  18.  
  19. Label the vacuum hoses at the sensor to aid during assembly. Disconnect the vacuum hoses, remove the retaining clips with a prytool and discard. Remove the sensor and mounting gasket.
  20.  
  21. Position the new gasket on the sensor and install sensor. Support the sensor on the outer diameter, and install the retaining clips.
  22.  
  23. Connect the vacuum hoses.
  24.  

2.6L Engines

See Figure 5



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Fig. Fig. 5: Heated air intake system-2.6L engines

  1. Verify all vacuum hoses and the flexible heat pipe between the air cleaner and heat stove are properly attached and in good condition.
  2.  
  3. On a cold engine with an ambient temperature less than 84°F (30°C) the heat door valve plate in the snorkel should be in the up position (Heat On).
  4.  
  5. With the engine running at normal operating temperature, the heat door should be in the down position (Heat Off).
  6.  
  7. If the heat door valve plate does not respond to hot and cold temperatures, the door diaphragm or the sensor may need replacing.
  8.  
  9. To test the diaphragm, remove the air cleaner from the engine and allow it to cool down to 84°F (30°C).
  10.  
  11. Connect a hand-operated vacuum pump to the sensor and apply 15 in. Hg (51 kPa) of vacuum. The valve should be in the up position (Heat On).
  12.  
  13. If the door does not raise to Heat On position, test the vacuum motor for proper operation.
  14.  
  15. Apply 10 in. Hg (34 kPa) of vacuum to the vacuum motor with a hand-operated vacuum pump, if the valve does not remain in the full up position, replace the air cleaner body assembly.
  16.  
  17. If the door performed adequately with vacuum applied to the motor, replace the sensor.
  18.  

REMOVAL & INSTALLATION



Heated Air Temperature Sensor

See Figure 6



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Fig. Fig. 6: Installing the heated air temperature sensor-2.5L engines

The heated air temperature sensor is located in the air cleaner housing and can be removed with the air filter removed from the housing.

  1. Remove the top of the air cleaner housing, this can be done by releasing the clips.
  2.  
  3. Remove the air filter.
  4.  
  5. Disconnect the vacuum lines from the sensor.
  6.  
  7. Remove the sensor from the housing by prying it carefully out.
  8.  

To install:
  1. Install the new sensor in position using a new gasket. Make sure the sensor is firmly seated.
  2.  
  3. Reconnect the vacuum lines to the sensor and reinstall the air filter.
  4.  

 
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