Sender: <marv@lancaironline.net>
To:  lml@lancaironline.net
Date: Sun, 15 May 2011 20:48:46 -0400
Message-ID: <redirect-4984695@logan.com>
Received-SPF: none
 receiver=logan.com; client-ip=209.86.89.61; envelope-from=colyncase@earthlink.net
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=dk20050327; d=earthlink.net;
  b=Hmbp7V9LiKPfqtDGJ+EIE6sE08dYoImumNJ0cFMGspmhU/fJij0jw7yiGgGW+4pM;
  h=Received:Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Content-Transfer-Encoding:Message-Id:References:To:X-Mailer:X-ELNK-Trace:X-Originating-IP;
Content-Type: text/plain; charset=us-ascii
Mime-Version: 1.0 (Apple Message framework v1082)
Subject: Re: [LML] Fuel restriction or air?
From: Colyn Case <colyncase@earthlink.net>
In-Reply-To: <list-4984183@logan.com>
Content-Transfer-Encoding: quoted-printable
References: <list-4984183@logan.com>

Did you verify the fuel vents are working properly?   ....and that the =
check valves on the vents are oriented correctly?

Also - what were the ambient temperatures?

Another more far out issue:   Is there a heat source in the engine =
compartment aimed at any fuel lines?   e.g. on my IV-P if the joints on =
the transfer tube leak, the gascolator and associated plumbing get the =
heat.  (Although I now have wrapped them in heat resistant covering).

On May 15, 2011, at 8:04 AM, Berni wrote:

> I have been trying to chase down the cause of a fuel issue in my =
normally aspirated Lancair IV engine.  During a cross country flight my =
fuel flow indicator began to show fluctuations which I mistakenly =
believed to be false readings.  Shortly thereafter during the same =
flight the engine began surging, slightly at first but increasingly =
worse in short time.  So much so that I began to plan for an emergency =
landing as I was looking to find the cause and to introduce a remedy.  I =
turned on my electric (back up) fuel pump and the engine immediately =
began to run strong and the fluctuation readings stabilized. =20
>=20
> After gaining altitude I turned off the electric pump and the unstable =
fuel flow readings as well as the engine surge returned.
>=20
> My initial take was that my problem was caused by a failing engine =
driven fuel pump.  Even with that belief (once back on the ground) I =
checked as much of the fuel system as possible looking for potential =
restrictions.  I looked at and cleaned the screens at the wing root =
connections as well as the inlet on the GAMI injectors.  I found no =
restrictions so I removed and exchanged my engine driven pump for a =
rebuilt unit.
>=20
> After installing the rebuilt pump the engine tested fine on the ground =
and fine in the air on a subsequent cross country trip.  Approximately =
2.1 hours of flying time later the exact same symptoms =
returned...erratic fuel flow readings followed closely by engine surge.
>=20
> I am now at a loss as to what I should now look for.  Could my problem =
be due to air somehow being introduced into my fuel flow?  Should I be =
looking at my fuel selector as a possible culprit?  If so how would I =
test that possibility?
>=20
> Any and all suggestions would be most appreciated.
>=20
> Sent from my iPad
> Berni Breen
> Bbreen@cableone.net
> --
> For archives and unsub =
http://mail.lancaironline.net:81/lists/lml/List.html