Reply-To: <jandre@nc.rr.com>
From: "Jeffery J. Andre'" <jandre@nc.rr.com>
To: "'Rotary motors in aircraft'" <flyrotary@lancaironline.net>
Subject: RE: [FlyRotary] Re: EWP - series pumps and wacky ideas
Date: Mon, 13 Oct 2003 17:55:46 -0400
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>  Does anyone know with any accuracy how fuel pumps fail?  I
> >doubt they fail catastrophically.  I suspect they fail by degrees
> >(probably very gradually as the poorly maintained filter clogs up).

My experience with two electric fuel pump failures (one GM, one Jeep).

They both started making a substantial amount of noise (high pitched whine)
which increased in volume over about a two-three weeks time, after which
they failed completely (siezed).  I assumed from that behaviour that one
failure mode for these things is bearing failure, and that you do get some
fairly obvious warning with plenty of time to do something about it.  Both
were in-tank sealed pumps, and I didn't take them apart to see what exactly
failed.  I suppose the bearings may have failed because the seals failed,
and allowed fuel into the bearings.

I would think contaimination, either through a clogged intake screen or
contaminants actually getting into the pump and "jamming" the impeller would
be another.

Jeff Andre'
Raleigh, NC