Fuel injectors, servicing: Notes
WARNING: This page is about a different car, the 1996 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.
The diesel fuel injectors for the AAZ engine are designed with two springs to control injector opening, and the injection of fuel takes place in two stages.
If these two-stage injectors malfunction they must be replaced, as opening pressure is not adjustable and they cannot be repaired.
Check 1st-stage opening pressure and check for leakage as described below.