Adjusting ALH Injection Pump Timing

In this video we will watch Corey from as he adjusts the injection pump timing on a 2003 Jetta TDI with engine code ALH.  He will overview both the mechanical adjustment and show the TDI Timing Graph feature of VCDS.


How to Adjust the Injection Pump Timing on the ALH Engine

Parts required:

Tools Required:

  • 13 mm socket & ratchet


  1. First, check your ALH injection pump timing to determine if you need to advance or retard the timing.
  2. Remove timing belt cover by unclipping the three metal clips.  Pull the cover up and out of the way.

    ALH Timing Cover Clips

    Three clips to remove the timing belt cover

  3. Located the Injection Pump Sprocket.  It is the front-most sprocket in the timing belt system.  It is held in place by 3 13mm head bolts.

    ALH Injection Pump Sprocket

    ALH Injection Pump Sprocket

  4. Break the three bolts loose, but do not remove.  You want these just past finger-tight on the sprocket.
  5. Setting the Timing: to set the timing you will need to use a 22mm wrench to turn the injection pump hub.  The sprocket is held in place by the belt, so you should be able to turn the hub without the sprocket turning.  A firm tap will move the timing quite a bit, so take it easy – our rule of thumb is if you can see the wrench move, you’ve moved too much!
    • Tap the wrench towards the REAR of the vehicle to retard the timing
    • Tap the wrench towards the FRONT of the vehicle to advance the timing
  6. Tighten the three injection pump sprocket bolts.  Turn the car on and check the injection pump timing again.  It will probably take a few tried until you get it spot on.
  7. Once you are happy with the timing, torque the bolts to 18 ft/lbs & reinstall the timing belt cover.


  1. […] If the timing needs to be adjusted, you can follow our Adjusting ALH Injection Pump Timing guide here. […]


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