Fuel Supply

Safety Precautions


Fuel pressure in the high pressure pipe can be up to 120 bar! Follow the safety precautions when releasing the high side pressure.

• Releasing the high side pressure. Refer to => [ High Side Fuel Pressure, Releasing ] Service and Repair.

• The fuel supply line is under pressure. Always wear protective eyewear and protective clothing to prevent injuries and fuel from coming in contact with your skin. Wrap a cloth around the connection before removing a fuel hose. Remove the hose connection carefully to release the pressure.

For safety reasons, switch off the current to the fuel pump before opening the fuel system. Otherwise the fuel pump will activate when the drivers door is opened. Use one of the following ways to switch off the current:

• Battery, disconnecting

or

• Remove the fuse for the fuel pump control module (J538)

or

• Disconnect the connector from the fuel delivery unit flange or the fuel pump control module (J538)


When doing any repair work, especially in the engine compartment, pay attention to the following due to clearance issues:

• Route all lines and wires in their original locations.

• Ensure sufficient clearance to all moving or hot components.

To reduce the risk of personal injury and/or damage to the fuel injection and ignition system, always observe the following:

• Do not touch or disconnect ignition coils with power output stages when the engine is running or turning at starting RPM.

• The ignition must be turned off before connecting or disconnecting injection and ignition system wiring or tester cables.

Always observe the following when removing and installing the fuel delivery unit or the fuel pump from a full or partially filled fuel tank.

• Before starting work, place the extracting hose from an exhaust extractor that is turned on near the fuel tank opening. This will extract the fuel vapors. If no exhaust extraction system is available, a radial fan (as long as motor is not in air flow) with a displacement greater than 15 m3/h can be used.

• Prevent fuel from contacting skin! Wear fuel-resistant gloves!

If special testing equipment is required during road test, note the following:

• Testing and measuring instruments must be secured on the rear seat and operated by a second person from that location.

• If the vehicle is involved in a collision while testing and measuring equipment is operated from the front passenger seat, the person sitting in that seat could be seriously injured when the airbag deploys.