Checking fuel pump capacity (B204i/E)
| WARNING | This check involves partial dismantling of the car's fuel system. The following points must be observed in connection with the work: Work only in a well-ventilated area! If approved equipment for the extraction of fuel vapors is available, be sure to use it. Wear suitable gloves! Prolonged contact with fuel can cause skin irritation or dermatitis. Keep a class BE fire extinguisher close at hand! Beware of sparks caused by short circuits and when connecting and disconnecting leads in electrical circuits. No smoking anywhere in the vicinity. |
Scheme 1
Scheme 2
- Detach the return line from the fuel rail. Use special tool no. 83 95 261. Remove the rubber seal from the quick-release coupling with a pair of flat-nose pliers. (Scheme 2): Detaching Return Line From Fuel Rail
- Connect the adapter and hose, special tool no. 83 94 918, to the return side of the fuel rail. Run the hose to a receptacle.
- Run the fuel pump for 30 seconds. Use battery voltage from fuse in (no. 4) coupled to fuse out (no. 32) in the fuse panel. Use jumper lead no. 83 93 886. (Scheme 3): Using Battery Voltage From Fuse In (No. 4) Coupled To Fuse Out (No. 32) In Fuse Panel While being run for 30 seconds, the pump should deliver at least 700 ml fuel to the receptacle. IMPORTANT: It is essential that great care is taken not to damage the sealing surface on the male part of the fuel line quick release coupling when it is disconnected. If the male part is excessively dirty, it should be cleaned before being released. In addition, clean the sealing surface after releasing it if necessary. Use a soft rag. Lubricate the male part before fitting.
- Disconnect the test equipment and reconnect the return line from the fuel rail.
Checking fuel pump capacity (B235R, B204L/R)
| WARNING | This check involves partial dismantling of the car's fuel system. The following points must be observed in connection with the work: Work only in a well-ventilated area! If approved equipment for the extraction of fuel vapors is available, be sure to use it. Wear suitable gloves! Prolonged contact with fuel can cause skin irritation or dermatitis. Keep a class BE fire extinguisher close at hand! Beware of sparks caused by short circuits and when connecting and disconnecting leads in electrical circuits. No smoking anywhere in the vicinity. |
Scheme 3
Scheme 4
Scheme 5
- Remove the engine cover. (Scheme 4): Removing Fuel Pump Fuse No. 32
- Remove the fuel pump fuse no. 32 while the engine is running. Turn off the ignition once the engine has stopped. Refit the fuel pump fuse no. 32.
- Detach the return line from the fuel rail. Use special tool no. 83 95 261. Remove the rubber seal from the quick-release coupling with a pair of flat-nose pliers. IMPORTANT: It is essential that great care is taken not to damage the sealing surface on the male part of the fuel line quick release coupling when it is disconnected. If the male part is excessively dirty, it should be cleaned before being released. In addition, clean the sealing surface after releasing it if necessary. Use a soft rag. Lubricate the male part before fitting.
- Connect the adapter and hose, special tool no. 83 94 918, to the return side of the fuel rail. Run the hose to a receptacle. (Scheme 5): Connecting Adapter And Hose, Special Tool No. 83 94 918, To Return Side Of Fuel Rail
- Connect the diagnostic tool and run the fuel pump for 30 seconds. While being run for 30 seconds, the pump should deliver at least 700 ml fuel to the receptacle.
- Disconnect the adapter with hose from the fuel rail return.
- Connect the return line to the fuel rail, lubricating the male part with acid-free vaseline, part no. 30 06 665, before connecting it. see scheme 43: Connecting Return Line To Fuel Rail
- Fit the engine cover.
Checking injector flow capacity (B235R, B205L/R)
| WARNING | This check involves partial dismantling of the car's fuel system. The following points must therefore be observed in connection with the work: Work only in a well-ventilated area! If approved equipment for the extraction of fuel vapors is available, be sure to use it. Wear suitable gloves! Prolonged contact with fuel can cause skin irritation or dermatitis. Keep a class BE fire extinguisher close at hand! Beware of sparks caused by short circuits and when connecting and disconnecting leads in electrical circuits. No smoking anywhere in the vicinity. |
| IMPORTANT | The utmost cleanliness must be observed when handling the fuel rails and injectors. Wash around the injectors, fuel rail and intake manifold and dry with compressed air. |
Scheme 6
Scheme 7
- Remove the fuel rail as described under Fuel rail (B235R, B205L/R).
- Attach the fuel connections to the fuel rail. Fit a transparent hose to the nozzle. The hose should be approx. 40 cm long with an inner diameter of 15 mm. see scheme 55: Fitting Transparent Hose To Nozzle
- Direct the hose into a receptacle/measuring glass.
- Plug in the connectors to their respective injectors.
- Start the fuel pump by connecting jumper lead, 83 93 886 Diagnostics cable, LH system, between the lower pin of fuse 32 for the fuel pump and the upper pin of fuse 4 for the luggage compartment lighting.
- Conduct the flow capacity test using the diagnostic tool. The diagnostic tool will then activate the injector in question with battery voltage for exactly 30 s. see scheme 56: Conducting Flow Capacity Test Using Diagnostic Tool
- After 30 seconds, the amount of fuel should be 176 +/- 7 ml. The difference between injectors must not exceed 14 ml.
- Change any defective injectors.
- Disconnect the fuel line connections from the fuel rail and fit the fuel rail as described under Fuel rail (B235R, B205L/R).
