Re: [DML] Noisy fuel pump

["M1" <PWPilot@xxxx>]

Walt;

Re: Noisy Fuel Pump.

I've been through quite a few situations with the fuel pump in '83. Without
going into all of the details at this time, I can say that from my
experiences the fuel pump, when receiving a sufficient supply of fuel runs
very quietly. The only time mine makes any real amount of noise is when the
pump itself is starved for fuel. The fuel starvation at the fuel pump inlet
causes cavitation ( air bubbles ), and these passing through the pump are
what makes the noise.

The cause of this on my car was bad parts in the fuel tank supply system:
defective filter material on the fuel tank baffle, and collapsed fuel hose
from tank baffle to the pump. The noise, in several episodes of fuel system
problems, was always the first sign of impending fuel pump failure.

Interestingly enough the fuel pump itself is actually cooled by the fuel
passing through it, and is a significant source of heat. The pump draws
about six amps: this results in about 60 watts of heat added to the fuel
over time. Strange as it may seem, the fuel actually passes directly over
the pump motor armature and the commutator brushes. The reason that this
does not cause an explosion is because the pump body is hermetically sealed,
and with no way for air to get in there can be no problems.

George Ryerson



-----Original Message-----
From: Scott Cagle <sharkywtrs@xxxx>
To: dmcnews@xxxxxxxxxxxxxxx <dmcnews@xxxxxxxxxxxxxxx>
Date: Tuesday, February 27, 2001 10:52 PM
Subject: Re: [DML] Noisy fuel pump
>
>Walt;
>
>I had the same problem this weekend. During the meeting of the ETDOC, at
the very tail end of the trip, mine started making some noise.