A guide to the early Volkswagen 4-cylinder IDI Diesel engines.
These are commonly found in the Rabbit, Jetta, Dasher, Rabbit Pickup and Vanagon. They’re a popular swap into the Suzuki Samurai, too.

This information was pulled from an obsolete dealer manual called ‘Diesel ProTraining’

• Diesel History
• Diesel Concepts and Basics
  1. Diesel Fuel Supply System
  2. Swirl Chamber / Injectors
  3. Injection Pump; Overview and Vane Pump
  4. Injection Pump; Distribution, Injection & Metering
  5. Injection Pump; Injection Timing Advance
  6. Glow Plugs, Fuel Shut-off Solenoid & Fuel Filter
  7. Engine Oil and Diesel Fuel
• Hard Start/ Cold Running Issues
  1. No Start, Cranking Speed Is Too Low
  2. No Start, Cranking Speed OK
  3. Cold Running / Starting Problems
• Mechanical  issues
  1. Check for revised parts
  2. Check valve clearance
  3. Check compression
  4. Check for air leaks
  5. Check for fuel leaks
  6. Perform idle speed drop test
  7. Check injectors
  8. Check / adjust valve timing
  9. Check / adjust cold start advance
  10. Check / adjust injection pump timing
  11. Check / adjust idle and maximum speed
  12. Check pump mounting brackets
• Idle Issues
  1. Idle speed high or low; cannot be adjusted
  2. Warm engine has rough idle, performs OK above idle
  3. Diagnosis II – Idle Problems
• Warm Running Problems
  1. Warm engine misfires or makes knocking noises
  2. Warm engine surges
  3. Warm engine lacks power and/or smokes excessively
• Vibration Problems
  1. Check for vibration damper
  2. Check / adjust engine mounts
  3. Adjust steering column / adjust idle speed
• Other Issues and Parts
  1. Oil filter and cooler installation
  2. Fuel Filter installation and draining
  3. Oil in air cleaner; 1.5L Rabbit and Pickup
  4. A/C compressor cut-out switch
  5. Cylinder head and gasket
  6. E-mode automatic transmission