1985 BMW 524tdFACTORY OEM SERVICE PROCEDURE

Injector Nozzles

NOTE: If engine has excessive knock, an injector needle may have seized. Accelerate engine several times without load. If this does not eliminate noise, injector nozzle must be replaced. Defective injector can be found by unscrewing each injector line (one at a time) until noise stops.
  1. Remove high pressure fuel injection and fuel return lines. Using a Nozzle Socket (T84P 9527 A), remove fuel injectors from engine.
    NOTE: Use only SAE approved calibration oil (208629), SAE (J967D), or ISO fluid (4173) to test fuel injectors.
  2. After filling Nozzle Tester (014 00300), with calibration fluid, connect injector to high pressure line of tester. Bleed air from line, and injector, by pumping tester handle several times.
  3. Check spray pattern test by operating tester lever in short fast strokes. Injector must have a tight cone-shaped pattern and fuel stream should break off sharply at end of each stroke.
  4. Operate tester lever slowly and completely (1-2 strokes per second). A "chatter" sound will occur if injector is operating properly.
  5. Check pressure by operating tester lever and observing pressure at which injector begins to spray. Check valve seat sealing by applying 200 psi (14 kg/cm2 ) below injector opening pressure, for 10 seconds. The injector must not drip.
  6. If fuel injector leaks, or has incorrect spray pattern/opening pressure, it must be replaced. Injectors cannot be repaired.
NOTE: The nozzle holding nut has a copper seal. DO NOT lose when removing and installing fuel injectors.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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