Toyota Cressida/Corona/Crown/MarkII 1970-1982 Repair Guide

Fuel Injected Vehicles

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IDLE ADJUSTMENT





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Fig. Fig. 1 Tachometer attachment for all US models with electronic ignition



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Fig. Fig. 2 The service connector is found on the left front fender apron



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Fig. Fig. 3 Idle speed adjustment screw location-4M-E and 5M-E engines



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Fig. Fig. 4 Shorting the idle adjusting connector



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Fig. Fig. 5 Idle adjusting harness special service tool

In order to complete this procedure, you will need a voltmeter and an EFI idle adjusting wiring harness (Special Service Tool 09842-4010) which is available at your Toyota dealer. If you do not have these tools, which are essential to this procedure, the car should be taken to a competent mechanic or dealership equipped for this procedure.

  1. Behind the battery on the left front fender apron is a service connector. Remove the rubber cap from the connector and connect the EFI idle adjusting wiring harness.
  2.  
  3. Connect the positive lead of the voltmeter to the red wire of the wiring harness and then connect the negative lead to the black wire.
  4.  
  5. Connect a tachometer as per the manufacturer's instructions.
  6.  
  7. Warm up the oxygen sensor by running the engine at 2500 rpm for about two minutes. The needle of the voltmeter should be fluctuating at this time; if not, turn the idle mixture adjusting screw until it does.
  8.  
  9. Set the idle speed to specifications (see Tune-Up Specifications chart) by turning the idle speed adjusting screw.
  10.  

The idle speed should be set immediately after warm-up while the needle of the voltmeter is fluctuating.

  1. The idle adjustment procedure is now complete. Follow the remaining steps for the 4M-E and 5M-E engines.
  2.  
  3. Remove the rubber cap from the idle adjusting connector and short both terminals of the connector with a wire
  4.  
  5. While the connector is still shorted, run the engine at 2500 rpm for two more minutes.
  6.  
  7. With the engine at idle and the connector still shorted, read and record the voltage shown on the voltmeter.
  8.  
  9. Remove the short circuit wire from the connector and then race the engine to 2500 rpm once.
  10.  
  11. Adust the idle mixture adjusting screw until the median of the indicated voltage range is the same as the reading taken in Step 8.
  12.  
  13. Replug the idle mixture adjusting screw hole. Disconnect the tachometer, the voltmeter and the special wiring harness. Replace the rubber caps on the service connector and idle adjusting connector.
  14.  

Dashpot
4M-E AND 5M-E ENGINES


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Fig. Fig. 6 Loosen the locknut and turn the adjusting screw to set the dashpot

  1. Fully open and then release the throttle valve.
  2.  
  3. The throttle valve should return to the idle position in approximately 3.5 seconds.
  4.  
  5. To adjust the return time, loosen the locknut and turn the adjusting bolt.
  6.  

 
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