Test prerequisite

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2005 BMW 325i, 2005 BMW 325Ci, 2004 BMW 325i, 2004 BMW 325Ci, and 2003 BMW 325i. However, it is still accessible from the selected car via links, so may be relevant.

The correct fuel pressure regulator has been installed.

Use the Electronic Parts Catalogue to check whether the correct fuel pressure regulator has been installed for the vehicle:

Connect test adapter.

The regulating function of the fuel pressure regulator must be ensured under all operating conditions. The fuel pump must always be able to generate a fuel pressure that is higher than the pressure that is adjusted by the pressure regulator.

The DME controls the injection period for which the injection rate is adjusted.

The fuel return line is depressurised at engine standstill and ignition key position 0.

The pressure regulator will close at engine standstill and ignition key position 0. The fuel pressure in the feed will be maintained for an extended period of time. A non-return valve will close in the fuel pump. This measure will maintain the fuel pressure in the fuel system. Extended start times are thereby prevented.

Let the engine run at idle and measure the fuel pressure.