1985 Mercedes Benz 190D AutomaticFACTORY OEM SERVICE PROCEDURE

Injection Nozzles

NOTE: For testing, use clean test oil or filtered diesel fuel only. When checking a nozzle, never place hand in front of jet nozzle.
  1. Prior to testing, check longitudinal bore for free passage. Clean with a .007" (.18 mm) diameter wire.
  2. Using Bosch Injector Tester (EFEP 60 H), energetically pump 5 times through injection nozzle on tester. Then test buzzing of nozzle, slowly actuating hand lever for this purpose (approximately 1 stroke per second).
  3. During short, fast partial strokes (or least 2 strokes per second) the pintle should be closed. Generate initial jet by moving hand lever slowly in downward direction (4-6 strokes). A vertical cord-like jet should come out of center bore.
    NOTE: On new nozzles it is rather difficult to generate the initial jet. Check longitudinal bore with cleaning needle of .007" (.18 mm) diameter for free passage.
  4. Move hand lever slowly in downward direction (approximately 1 stroke per second) and check opening pressure. Opening pressure should be approximately 1667-1812 psi (117-127 kg/cm2 ). Shutoff valve on pump must be open during test.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
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