How do you test fuel pressure on 560sel?

To test fuel pressure on a Mercedes-Benz 560SEL, you need to access the fuel rail and connect a fuel pressure gauge to the test port. First, ensure the ignition is in the "on" position without starting the engine to check the pressure at key-on. The typical fuel pressure should be around 30-40 psi; if it's outside this range, you may need to inspect the fuel pump, filter, or pressure regulator. Always follow safety precautions when working with fuel systems.