Toyota Celica/Supra 1971-1985 Repair Guide

Voltage Regulator

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All 1971-79 models are equipped with a separate, adjustable regulator. The 1980-85 models are equipped with a transistorized regulator which is attached to the brush assembly on the side of the alternator housing. If faulty, it must be replaced; there are no adjustments which can be made.

REMOVAL & INSTALLATION



1971-79 Models
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the wiring harness at the back of the regulator.
  4.  
  5. Remove the regulator mounting bolts.
  6.  
  7. Remove the regulator.
  8.  

To install:
  1. Attach the regulator and tighten the mounting bolts.
  2.  
  3. Attach the electrical harness to the unit.
  4.  
  5. Connect the negative battery cable.
  6.  

1980-85 Models
  1. Remove the alternator as detailed earlier.
  2.  
  3. Remove the two screws on the back of the alternator housing and then remove the regulator end cover.
  4.  
  5. Underneath the end cover there are three terminal screws, remove them.
  6.  
  7. Remove the two regulator mounting screws and remove the regulator.
  8.  
  9. Using a small flat bladed tool, pry out the plastic housing and the rubber seal around the regulator terminals.
  10.  
  11. Installation is in the reverse order of removal.
  12.  

ADJUSTMENTS



Voltage
  1. Connect a voltmeter up to the battery terminals. Negative (black) lead to the negative (-) terminal; positive (red) lead to positive (+) terminal.
  2.  
  3. Start the engine and gradually increase its speed to about 1,500 rpm.
  4.  
  5. At this speed, the voltage reading should fall within the range specified in the Alternator and Regulator Specifications chart.
  6.  
  7. If the voltage does not fall within the specifications, remove the cover from the regulator and adjust it by bending the adjusting arm.
  8.  
  9. Repeat Steps 2 and 3 if the voltage cannot be brought to specification, proceed the mechanical adjustments which follow.
  10.  

Mechanical

Perform the previously outlined voltage adjustment, before beginning the mechanical adjustments.

FIELD RELAY

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Field relay adjustment component locations

  1. Remove the cover from the regulator assembly.
  2.  
  3. Use a feeler gauge to check the amount that the contact spring is deflected while the armature is being depressed.
  4.  
  5. If the measurement is not within specifications (see the Alternator and Regulator Specifications chart), adjust the regulator by bending the point holder P 2 (see the illustration).
  6.  
  7. Check the point gap with a feeler gauge against the specifications in the chart.
  8.  
  9. Adjust the point gap, as required, by bending the point holder P 1 (see the illustration).
  10.  
  11. Clean off the points with emery cloth if they are dirty and wash them with solvent.
  12.  

ARMATURE AND POINT GAPS

See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: Voltage regulator adjustment component locations

  1. Use a feeler gap to measure the air (armature) gap. If it is not within specification (see the Alternator and Regulator Specifications Chart), adjust it by bending the low speed point holder (PL 1 in the illustration).
  2.  
  3. Check the point gap with a feeler gauge. If it is not within specifications, adjust it by bending the high speed point holder (PL 2 in the illustration). Clean the points with emery cloth and wash them off with solvent.
  4.  
  5. Check the amount of contact spring deflection while depressing the armature. The specification should be the same as that for the contact spring on the field relay.
  6.  

 
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