BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

Fuel Injectors

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REMOVAL & INSTALLATION



See Figure 1



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Fig. Fig. 1: Check the O-rings when installing the fuel injector

Replace fuel injectors with like units. Different manufacturers where used for the fuel injectors, Bosch being the predominant supplier. In March 1991 Lucas fuel injectors where installed in the M30 engines. They function and test the same way as the Bosch units, but the 2 manufacturers injectors should not be mixed on the same engine.

M20 Engine
  1. Remove the intake manifold support from the manifold and valve cover.
  2.  
  3. Disconnect the fuel injector electrical plug plate lead under the intake manifold.
  4.  
  5. Disconnect the 2 coolant temperature sensors. Pull up and remove the fuel injector electrical plug plate.
  6.  
  7. Remove the 4 mounting bolts and pull the fuel rail up and out of the intake manifold. Remove the fuel injectors from the fuel rail.
  8.  

To install:
  1. Check the O-rings on the injector and replace if necessary. Check that all the injectors are of like types. Lightly grease the O-rings with petroleum jelly and install on the fuel rail.
  2.  
  3. Install the fuel rail on the manifold and tighten the bolts to 6.5-8.0 ft. lbs. (9-11 Nm). Install the electrical plate and connectors.
  4.  
  5. Connect the temperature sensors and the fuel injector electrical plate. Install the intake manifold support and tighten the bolts to 15-17 ft. lbs. (20-24 Nm).
  6.  

M30 Engine
  1. Remove the air intake hose passing over the fuel rail. Remove the plastic caps from the fuel rail cover.
  2.  
  3. Remove the 2 5mm setscrews from the fuel injector electrical plug plate. Pull up on the plug plate to remove.
  4.  
  5. Remove the 3 fuel rail bolts and pull up on the fuel rail. Disconnect the plugs from the injectors. Remove the retainers and the fuel injectors from the fuel rail.
  6.  

To install:
  1. Check the O-rings on the injector and replace if necessary. Check that all the injectors are of like types. Lightly grease the O-rings with petroleum jelly and install on the fuel rail. Connect the electrical plugs.
  2.  
  3. Install the fuel rail on the manifold and tighten the bolts to 6.5-8.0 ft. lbs. (9-11 Nm). Install the electrical plug plate and the 2 5mm setscrews.
  4.  
  5. Install the fuel rail cover and the plastic plugs. Install the air intake hose.
  6.  

M42 Engine

See Figures 2, 3 and 4



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Fig. Fig. 2 Upper manifold retaining nuts and vacuum line-M42 engine



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Fig. Fig. 3 These vacuum hoses must be secure when installing the manifold-M42 engine



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Fig. Fig. 4 Fuel connections and mounting of the fuel rail-M42 engine

  1. Remove the upper section of the intake manifold.
  2.  
  3. Remove the electrical plug plate from the injectors. Disconnect the fuel lines from the fuel rail.
  4.  
  5. Remove the fuel rail mounting bolts and pull the fuel rail with injectors up and off. Remove the retainers and the injectors from the fuel rail.
  6.  

To install:
  1. Check the O-rings on the injector and replace if necessary. Check that all the injectors are of like types. Lightly grease the O-rings with petroleum jelly and install on the fuel rail.
  2.  
  3. Install the fuel rail on the lower manifold and tighten the bolts to 6.5-8.0 ft. lbs. (9-11 Nm). Connect the fuel lines. Install the electrical plug plate and the upper intake manifold.
  4.  

M50 Engine

See Figures 5 and 6



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Fig. Fig. 5: Fuel feed hose connection to the fuel rail-M50 engine



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Fig. Fig. 6: The fuel rail is on the right and the injector plug plate on the left is shown with the cover loosened to show the interior wiring. It is not necessary to uncover the wiring when removing the plug plate-M50 engine

  1. On the E36 3 Series with this engine, remove the DME module housing cover screws on the right side of the firewall. Remove the rubber strips along the wire duct by pulling up. Remove the screws from the wire duct and pull it out. This will allow enough movement in the injector wires to remove the injector electrical plug plate.
  2.  
  3. Remove the oil filler cap and the valve cover cladding. Remove the injector area cover.
  4.  
  5. Disconnect the fuel feed at the front of the fuel rail. Remove the 2 screws holding the injector electrical plug plate. Pull up and remove from the injectors.
  6.  
  7. Disconnect the fuel return line. Remove the 2 bolts holding the fuel rail and remove the fuel rail by pulling off with the injectors. Remove the injectors from the fuel rail.
  8.  

To install:
  1. Check the O-rings on the injector and replace if necessary. Check that all the injectors are of like types. Lightly grease the O-rings with petroleum jelly and install on the fuel rail.
  2.  
  3. Install the fuel rail and tighten the bolts to 6.5-8.0 ft. lbs. (9-11 Nm). Connect the fuel lines. Install the electrical plug plate.
  4.  
  5. Install the fuel rail cover and the valve cover cladding with the oil filler cap. Install the wire duct and the rubber stripping.
  6.  

S14 Engine
  1. Remove the bolts from the fuel rail. Disconnect the throttle switch electrical plug.
  2.  
  3. Pull up and remove the fuel injector electrical plug plate.
  4.  
  5. Disconnect the fuel lines and pressure regulator vacuum hose.
  6.  
  7. Pull the fuel rail up and out of the intake manifold. Remove the fuel injectors from the fuel rail.
  8.  

To install:
  1. Check the O-rings on the injector and replace if necessary. Check that all the injectors are of like types. Lightly grease the O-rings with petroleum jelly and install on the fuel rail.
  2.  
  3. Install the fuel rail on the manifold and tighten the bolts to 6.5-8.0 ft. lbs. (9-11 Nm). Install the electrical plate and connectors.
  4.  

S38 Engine
  1. Remove the bolts from the fuel rail. Disconnect the idle speed control valve electrical plug.
  2.  
  3. Pull up and remove the fuel injector electrical plug plate.
  4.  
  5. Disconnect the fuel lines and pressure regulator vacuum hose.
  6.  
  7. Pull the fuel rail up and out of the intake manifold. Remove the fuel injectors from the fuel rail.
  8.  

To install:
  1. Check the O-rings on the injector and replace if necessary. Check that all the injectors are of like types. Lightly grease the O-rings with petroleum jelly and install on the fuel rail.
  2.  
  3. Install the fuel rail on the manifold and tighten the bolts to 6.5-8.0 ft. lbs. (9-11 Nm). Install the electrical plate and connectors.
  4.  

 
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