Fuel System Pressure Release
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 2003 BMW Z8, 2003 BMW Z4, 2003 BMW X5, 2003 BMW M5, and 2003 BMW M3. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
ALWAYS relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components.
Wrap a rag around fuel line. Open fuel line slowly.