Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Timing Procedures

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CAUTION
When performing this or any other operation with the engine running, be very careful of the alternator belt and pulleys. Make sure that your timing light wires don't interfere with the belt.

INSPECTION AND ADJUSTMENT



Breaker Point Ignition Systems
  1. Attach a timing light and a dwell/tachometer.
  2.  
  3. Locate the timing mark opening in the bellhousing of the transaxle. The "OT" mark stands for TDC or zero advance. There is another mark which designates the correct timing position. DON'T disconnect the vacuum line at the distributor.
  4.  
  5. Start the engine and allow it to reach the normal operating temperature. The engine should be running at normal idle speed.
  6.  
  7. Shine the timing light at the marks.
  8.  
  9. The timing mark and the V-shaped pointer should be aligned.
  10.  
  11. If not, loosen the distributor hold-down bolt and rotate the distributor very slowly to align the marks.
  12.  
  13. Tighten the mounting nut when the ignition timing is correct.
  14.  
  15. Recheck the timing when the distributor is tight.
  16.  

Electronic Ignition Systems
1979-84 MODELS
  1. Run the engine to operating temperature. Connect a tachometer.
  2.  

On carbureted models with electronic ignition, a special adaptor must be used to connect a tachometer to the engine. Refer to theelectronic ignition precautionsin this section for a description on how to construct your own. Failure to use an adaptor on these engines may cause ignition system damage.

  1. Stop the engine. If equipped, disconnect the idle stabilizer plugs at the control unit and plug them together. On carbureted Rabbits, disconnect and plug the vacuum advance/retard hoses.
  2.  
  3. Switch all electrical accessories to the OFF position.
  4.  
  5. Start the engine and check the idle speed. Adjust, if it is out of specification.
  6.  
  7. With your timing light, check that the pointer lines up with the notch in the flywheel. To adjust the timing, loosen the distributor hold-down bolt and rotate the distributor very slowly to align the marks.
  8.  
  9. On carbureted Rabbits, connect the vacuum hose(s). Idle speed should drop to 600-750 rpm.
  10.  
  11. Stop the engine, then reconnect the plugs at the control unit. On carbureted Rabbits, start the engine and accelerate it a few times. The idle speed should now be 850-950 rpm.
  12.  

1985-89 8 VALVE ENGINES

See Figure 1

  1. Run the engine for a few minutes to allow it reach normal operating temperature. Wait for the cooling fan to come on once. Make sure all electrical accessories are in the OFF position. On Digifant II engines, raise the idle speed to a minimum of 2,100 rpm four times to cancel the (computer controlled) hot start idle speed increase function, then allow the engine to idle normally. If you don't do this step, the hot re-start program stored in the computer will cause the engine idle speed to run higher than normal and affect the timing adjustment.
  2.  
  3. Stop the engine.
  4.  
  5. If equipped, disconnect the vacuum hose from the distributor and plug it. On Digifant II engines, unplug the coolant temperature sensor connector. The connector is usually blue and is attached directly to the coolant temperature sensor.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: Coolant temperature sensor location on Digifant II engines

  1. Connect a timing light and tachometer.
  2.  
  3. Start the engine and check the timing. The pointer must line up with the notch in the flywheel. On Digifant II engines, briefly raise the engine speed to 3,000 rpm 3 times, then check idle speed and timing again.
  4.  
  5. If the timing is not as specified, loosen the distributor base clamp and rotate the distributor clockwise or counterclockwise until the timing is within specs.
  6.  
  7. Tighten the distributor clamp and clamp base bolt.
  8.  
  9. Once the clamp base bolt is tight, check the timing again.
  10.  
  11. Check the idle speed and adjust if necessary.
  12.  
  13. Stop the engine, then disconnect the timing light and tachometer. Connect the wiring for the coolant temperature sensor or connect the distributor vacuum line (if required).
  14.  

16 VALVE ENGINES
  1. Run the engine for a few minutes to allow it reach normal operating temperature. Wait for the cooling fan to come on once.
  2.  
  3. Stop the engine, then connect a timing light and tachometer.
  4.  
  5. Start the engine and check the timing. The pointer in the hole must line up with the notch in the flywheel.
  6.  
  7. If the timing is not as specified, remove the cap that covers the head of the distributor base clamp bolt (if installed). Loosen the distributor base clamp and rotate the distributor clockwise or counterclockwise until the timing is within specification.
  8.  
  9. Tighten the distributor clamp and clamp base bolt.
  10.  
  11. Once the clamp base bolt is tight, check the timing again.
  12.  
  13. Check the idle speed and adjust if necessary.
  14.  
  15. Stop the engine, disconnect the timing light and tachometer.
  16.  

 
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