Mazda Trucks 1994-1998 Repair Guide

Idle Speed and Mixture Adjustments

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Navajo and B Series Pick-up Models

The engines covered by this manual utilize sophisticated multi-port fuel injection systems in which an engine control computer utilizes information from various sensors to control idle speed and air fuel mixtures. No periodic adjustments are either necessary or possible on these systems. If a problem is suspected, please refer to Chapters 4 and Chapters 5 of this manual for more information on electronic engine controls and fuel injection.

MPV Models

The air/fuel mixture is computer controlled according to the needs of the engine and is not adjustable. If the air/fuel mixture is too lean or too rich, other problems with the engine and/or engine control system exist. The following adjustment applies only to the idle speed.

1994-95

See Figures 1 and 2

  1. Apply the parking brake. Place the shift lever in P .
  2.  
  3. Start the engine and bring to normal operating temperature. Make sure all accessories are OFF .
  4.  
  5. Connect a tachometer to the engine according to the manufacturer's instructions.
  6.  
  7. Check the idle speed and adjust, if necessary; it should be 750-790 rpm for 2.6L engines or 780-820 rpm for 3.0L engines.
  8.  
  9. Connect a jumper wire between the TEN terminal and the GND terminal of the data link connector.
  10.  
  11. Adjust the idle speed by turning the air adjusting screw.
  12.  



Click image to see an enlarged view

Fig. Fig. 1: Turn the air adjusting screw-3.0L engine



Click image to see an enlarged view

Fig. Fig. 2: Turn the air adjusting screw-2.6L engine

  1. Remove the jumper wire.
  2.  
  3. Remove all test equipment.
  4.  

1996-98
  1. Apply the parking brake and place the gearshift lever in P .
  2.  
  3. Start the engine and bring to normal operating temperature. Make sure all electrical loads and the A/C switch are OFF .
  4.  
  5. Connect a tachometer to the engine according to the manufacturer's instructions.
  6.  
  7. Connect the SST 49 B019 9A0 (system selector) to the data link connector.
  8.  
  9. Set the switch A to position No. 1 and set the test switch to SELF TEST. Verify that the idle speed is within 760-800 rpm.
  10.  
  11. Adjust the idle speed by turning the air adjusting screw.
  12.  
  13. Remove all test equipment.
  14.  

 
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