At 01:05 PM 6/28/2009, Ken Lewis wrote:
>   Lowering the voltage mostly changes the speed and hence frequency emited,
>by the fuel pump (I did some experimenting where I ran the engine
>electronics off solar powered batteries).  It is still just as loud. I am
>wondering if the rubber vibration isolation stand-off has hardened over
>time. It might be easier to invest time and energy in that area instead.

Right.  What I'm proposing would only be useful if the noise was
resulting from cavitation arising from inlet restrictions.

 From my own experience with clogged inlet filters, the cavitation
noise is a high-pitched whine that is clearly audible from ground
level alongside the running vehicle, whereas a properly running pump
is inaudible or nearly so.  Likewise, a correctly running pump cannot
be heard from inside with the engine running, while the cavitating
pump is clearly audible.

I'm embarrassed to say that on Dutiful Passage I swapped in under
warranty from Auto-Zone a perfectly good Pierburg pump (not to
mention replacing the original Bosch pump) through not understanding
this problem.

  --
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'89 Po' White Star "Scamp"