BMW Coupes and Sedans 1970-1988 Repair Guide

Diesel Engines


See Figures 1 and 2

Diesel engines use a fuel delivery system unique to diesel powered models.

Before checking or adjusting the engine idle, make sure the vehicle is in a well ventilated area, and the transmission is in NEUTRAL or PARK with the wheels securely blocked for your protection.

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Fig. Fig. 1: Check the play between the screw and the throttle lever

  1. Valve clearance must be correct.
  3. Run the engine until it reaches operating temperature. Make sure all electrical accessories are OFF . Check to make sure the throttle lever is resting on the idle adjusting screw, then shut the engine OFF .

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Fig. Fig. 2: To adjust the idle, loosen the locknut (1) and turn the screw (2)

  1. Check the play between the throttle lever and the knurled screw. It should be 0.011-0.019 inches (0.30-0.50mm). Hold the hexagonal nut associated with the screw with the knurled head, and then turn that screw until the play is correct.
  3. Loosen the locknut (1) and turn the adjusting screw (2) to give the correct idle speed. Tighten the locknut.
  5. Repeat the clearance check of Step 2. If not to specification, readjust the clearance as in Step 3. On cars with automatic transmission, check the distance from the linkage to the rear injection pump flange and adjust if necessary (see the section below covering transmission linkage adjustments).