Mercedes Coupes/Sedans/Wagons 1974-1984 Repair Guide

Mechanical Fuel Pump

Print

All Mercedes-Benz carbureted engines use a diaphragm type fuel pump, which is mounted on the side of the block. It is operated by a gear driven eccentric shaft through a rocker arm on the fuel pump.

REMOVAL & INSTALLATION



  1. Clean the joint around the fuel pump base and cylinder block.
  2.  
  3. One at a time, remove and plug the intake and outlet lines from the fuel pump.
  4.  
  5. Unbolt the retaining bolts and remove the fuel pump and gasket from the cylinder block.
  6.  

To install:
  1. Clean the mating surfaces of the engine and cylinder block.
  2.  
  3. Install a new gasket.
  4.  
  5. Insert the fuel pump into the block and install the retaining bolts. Be sure that the bolts are tightened evenly.
  6.  
  7. Reconnect the intake and outlet lines to the fuel pump.
  8.  
  9. Run the engine and check for leaks.
  10.  

TESTING DELIVERY PRESSURE



  1. Remove the wire from the coil to prevent starting.
  2.  
  3. Connect a pressure gauge into the output line of the fuel pump.
  4.  
  5. Crank the engine and read the delivery pressure on the pressure gauge. The pressure should be a constant 1.5-2.5 psi.
  6.  
  7. If the pressure is not within specifications or is erratic, remove the pump for service or for replacement with a new or rebuilt unit. No adjustment is provided.
  8.  

 
label.common.footer.alt.autozoneLogo