While driving slowly with low RPM or while idling, a faint knocking or fluttering noise can be heard from the fuel tank with a low fuel level (less than two gallons).
Note that if the noise continues with the fuel cap removed, the noise may be related to the fuel pump itself.
The first part of this bulletin applies to all BMW vehicles except the F48. While driving slowly with low RPM or while idling, a faint knocking or fluttering noise can be heard from the fuel tank with a low fuel level (less than two gallons).
It may sound like a helicopter noise from the rear of the vehicle. Pressure fluctuations from the tank ventilation valve will cause the fuel tank filler pipe non-return valve to vibrate. Check the integration level of the vehicle. If it is not already F020-19-03-540 or higher, then reprogram the vehicle with ISTA 4.17.1X or higher.
If F48, if it is not already F056-20-03-540 or higher, reprogram with ISTA 4.23.1X or higher.
Note that if the noise continues with the fuel cap removed, the noise may be related to the fuel pump itself.
Mike Mavrigian has written thousands of automotive technical magazine articles involving a variety ofspecialties, from engine building to wheel alignment, and has authored more than a dozen books that crisscross the automotive spectrum. Mike operates Birchwood Automotive, an Ohio shop that builds custom engines and performs vintage vehicle restorations. The shop also features a professional photo studio to document projects and to create images for articles and books.
