BMW Coupes and Sedans 1970-1988 Repair Guide

Mechanical Fuel Pump


See Figures 1 and 2

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Fig. Fig. 1: An example of a mechanical fuel pump-2002 model

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Fig. Fig. 2: Exploded view of a mechanical fuel pump


Insert a tee in the fuel pump discharge line where it enters the carburetor. Connect a gauge rated at about 10 psi (68 kPa) to the open end of the tee. Run the engine at 4,000 rpm. The pressure should be 3.0-3.5 psi (20-24.0 kPa).


  1. Remove the air cleaner. Disconnect and plug the 2 fuel lines.
  3. Remove the 2 retaining nuts and pull the pump off the cylinder head. Pull the insulator block off and the pushrod out.
  5. If there is any evidence of wear, check the length of the pushrod. It should be 3.4 inches (88mm) on 4-cylinder models and 4.7 inches (119mm) on 6-cylinder vehicles.
  7. Install in reverse order. Do not use sealer on the insulator block, as this will change the effective length of the pushrod.