Fuel is extremely flammable, so take extra precautions when working on any part of the fuel system. Do not smoke and do not allow open flames and lamps without shades near the working area. Do not work in garages with natural gas equipment with a wick (types of water heaters and clothes dryers). If fuel comes into contact with skin, wash immediately with soap and water. When carrying out any work on the fuel system, wear safety goggles and keep a fire extinguisher ready.
Examination
Vehicle check
1. Using a mechanical stethoscope (available at most auto supply stores) check when the engine is idling for clicks in each injector (Look illustration).
If a mechanical stethoscope is not available, clicks in the injectors can be checked with a screwdriver. Place the end of the screwdriver on the injector, and press the handle against your ear.
2. When working, the injectors create a steady clicking sound.
3. Increase engine speed above 3500 rpm. The click frequency should increase with engine speed.
4. If the injector does not work (no clicks), purchase a special injector test lamp from an auto supply store and connect it to the injector electrical connector. Start the engine and check the resistance that the lamp is flashing. This means that the correct voltage is being supplied to the injector, so the injector itself is faulty.
5. Disconnect the connector of each injector and check the resistance of the injectors. Compare the results with those given in Table of sizes and adjustment data at the end of the Values Guide. Replace all injectors with incorrect resistance value.
Volume check
Since a special injector tester is required to perform an injector volume test, this procedure is beyond the capabilities of a home workshop. Have the injector volume check done by a BMW dealer or other specialist.
Replacement
1. Disconnect the main electrical connector of the fuel injector cable. Remove the inlet pipeline (see Honor Repair work carried out without removing the engine from the car).
2. Disconnect the fuel hoses from the fuel line and unscrew the fuel line fastening bolts (shown by arrows).
3. Remove from the inlet pipeline a fuel highway/injectors in gathering.
4. Installation is reverse to removal. Be sure to replace all O-rings. To prevent damage to the rings during installation, lubricate them with a thin layer of impellent oil. Pressurize the fuel system (install the fuel pump fuse and turn on the ignition) and check for leaks before starting the engine.