Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Airflow Sensor Potentiometer

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REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Unplug the electrical connection from the potentiometer.
  4.  
  5. Remove the screws securing the potentiometer, then remove it from the airflow sensor assembly.
  6.  

To install:
  1. Install the potentiometer on the airflow sensor. Thread the screws in, but they should still be loose.
  2.  
  3. Engage the electrical connection.
  4.  
  5. Adjust the potentiometer.
  6.  
  7. Connect the battery cable.
  8.  

ADJUSTMENT



4-Cylinder Models

See Figures 1, 2 and 3

  1. Lift the sensor plate up to the lower edge (on the fuel distributor side) of the airflow sensor. This can be done with tool VW 1348/1.
  2.  



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Fig. Fig. 1: Tool VW 1348/1 can be used to lift the sensor plate

  1. Connect jumper harness VW 1501 between the potentiometer and the connector. Connect a voltmeter to terminals 2 and 3 on 16-valve engines and to terminal 2 and ground on other models. Switch the meter to the DC 20 volt range.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Jumper harness 1501 and terminal designations



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Fig. Fig. 3: Potentiometer terminal designations

  1. Turn the ignition ON . Adjust the potentiometer so that the meter displays between 0.02-0.2 volts on 16-valve engines and 0.2-0.3 volts on other models, then tighten the screws.
  2.  
  3. Lift the sensor plate up to its stop. The meter should display approximately 7 volts. Lock the screws with a sealing compound or paint.
  4.  

5-Cylinder Models

See Figure 4

  1. Place tool VW 1348/1 centrally on the edge of the airflow sensor assembly. Pointer (3) faces the center of the fuel distributor.
  2.  
  3. Push the adjusting slide (2) down onto its stop. Turn setting screw (1) clockwise until the magnetic end contacts the airflow sensor plate retaining bolt.
  4.  
  5. Connect jumper harness VW 1501 between the potentiometer and the connector. Connect a voltmeter to terminals 2 and 3 of the harness. Switch the meter to the DC 20 volt range.
  6.  
  7. Turn the ignition ON . Pull slide (2) of the adjusting device into the first detent (idle position). Adjust the potentiometer until 0.2-0.5 volts is displayed. Tighten the potentiometer adjusting screws.
  8.  
  9. Pull slide (2) into the second detent (full throttle position). The meter should display 4-4.5 volts. Lock the screws with a sealing compound or paint.
  10.  

 
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