X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 15 May 2011 20:48:45 -0400 Message-ID: X-Original-Return-Path: Received: from snt0-omc3-s31.snt0.hotmail.com ([65.55.90.170] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with ESMTP id 4984304 for lml@lancaironline.net; Sun, 15 May 2011 10:27:17 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.55.90.170; envelope-from=scottekeighan@sympatico.ca Received: from SNT129-W7 ([65.55.90.136]) by snt0-omc3-s31.snt0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Sun, 15 May 2011 07:26:41 -0700 X-Original-Message-ID: X-Original-Return-Path: scottekeighan@sympatico.ca Content-Type: multipart/alternative; boundary="_86a4d6c9-7af0-4740-8c8c-2a7f00a2242a_" X-Originating-IP: [65.94.89.35] From: Scott E Keighan X-Original-To: Subject: RE: [LML] Fuel restriction or air? X-Original-Date: Sun, 15 May 2011 14:26:41 +0000 Importance: Normal In-Reply-To: References: MIME-Version: 1.0 X-OriginalArrivalTime: 15 May 2011 14:26:41.0687 (UTC) FILETIME=[1BFAFA70:01CC130C] --_86a4d6c9-7af0-4740-8c8c-2a7f00a2242a_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I had the exact same issue 2 years ago. It took me 6 weeks to finally trac= k down the problem. I did the same things as yourself as in dismantaling the engine driven fuel= pump=2C took the entire fuel system apart from the engine pump to the injectors=2C checked all the fittings and connectors from the t= anks to the engine etc. =20 An auto mechanic told me how to find the problem=2C vacuum not pressure. = Lots of time a system will hold pressure but not a vacuum.=20 =20 My issue was a broken o-ring on the fitting for the electric fuel pump (got= old and brittle). Air was being sucked into the system via the broken o-ring. This is what you do to check for this. Go t= o Harbor freight and get a hand pump vacuum pump (around $29). Remove the fuel line at the engine fue= l pump and make a fitting that will work with the vacuum pump. Place your fuel valve to th= e off position. Try to get some of the fuel out of the line by the vacuum pump as the fuel will ruin the di= aphram at the pump (i learned this the hard way). The pump will hold a vacuum if everything is ok. If there = is a leak start to disconnect fittings and cap them off between the fuel selector valve and the pump to determine = where the leak is. =20 Another check is to run the electric fuel pump with the mixture at idle cut= off. Have enough fuel in the tanks to cover the fuel return ports in the tanks. If you hear bubbles in the tank then air i= s getting induced into the system. (mine did this also). =20 Good luck Scott Keighan LIV=20 =20 =20 =20 =20 > To: lml@lancaironline.net > Date: Sun=2C 15 May 2011 08:04:47 -0400 > From: bbreen@cableone.net > Subject: [LML] Fuel restriction or air? >=20 > 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 in= dicator began to show fluctuations which I mistakenly believed to be false = readings. Shortly thereafter during the same flight the engine began surgin= g=2C slightly at first but increasingly worse in short time. So much so tha= t I began to plan for an emergency landing as I was looking to find the cau= se and to introduce a remedy. I turned on my electric (back up) fuel pump a= nd 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 fu= el 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 mu= ch of the fuel system as possible looking for potential restrictions. I loo= ked 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 excha= nged my engine driven pump for a rebuilt unit. >=20 > After installing the rebuilt pump the engine tested fine on the ground an= d fine in the air on a subsequent cross country trip. Approximately 2.1 hou= rs of flying time later the exact same symptoms returned...erratic fuel flo= w 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 poss= ibility? >=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.ht= ml = --_86a4d6c9-7af0-4740-8c8c-2a7f00a2242a_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I had the exact same issue 2 years ago. =3B It took me 6 weeks to final= ly track =3Bdown the problem.
I did the same things as yourself as in dismantaling the engine driven fuel= pump=2C =3Btook the entire fuel system apart from the engine
pump to the injectors=2C checked all the fittings and connectors from the t= anks to the engine =3Betc.
 =3B
An auto mechanic told me how to find the problem=2C =3B vacuum not pres= sure. =3B Lots of time a system will hold =3Bpressure but not
a vacuum. =3B
 =3B
My issue was a broken o-ring on the fitting for the electric fuel pump (got= old and brittle). =3B Air was being sucked into the
system via the broken o-ring. =3B This is what you do to check for this= . =3B Go to Harbor freight and get a
hand pump vacuum pump (around $29). =3B Remove the fuel line at the eng= ine fuel pump and make
a fitting that will work with the vacuum pump. =3B Place your fuel valv= e to the off position. =3B Try to get some
of the fuel out of the line by the vacuum pump as the fuel will ruin the di= aphram at the pump (i learned this
the hard way). =3B The pump will hold a vacuum if everything is ok.&nbs= p=3B If there is a leak start to disconnect fittings
and cap them off between the fuel selector valve and the pump to determine = where the leak is.
 =3B
Another check is to run the electric fuel pump with the mixture at idle cut= off. =3BHave enough fuel in the tanks to cover the
fuel return ports in the tanks. =3B If you hear bubbles in the tank the= n air is getting induced into the system. (mine did this also).
 =3B
Good luck
Scott Keighan
LIV =3B
 =3B
 =3B
 =3B

 =3B
>=3B To: lml@lancaironline.net
>=3B Date: Sun=2C 15 May 2011 08:04:4= 7 -0400
>=3B From: bbreen@cableone.net
>=3B Subject: [LML] Fuel r= estriction or air?
>=3B
>=3B I have been trying to chase down th= e 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 wh= ich I mistakenly believed to be false readings. Shortly thereafter during t= he same flight the engine began surging=2C slightly at first but increasing= ly worse in short time. So much so that I began to plan for an emergency la= nding as I was looking to find the cause and to introduce a remedy. I turne= d on my electric (back up) fuel pump and the engine immediately began to ru= n strong and the fluctuation readings stabilized.
>=3B
>=3B Aft= er gaining altitude I turned off the electric pump and the unstable fuel fl= ow readings as well as the engine surge returned.
>=3B
>=3B My i= nitial 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 m= y engine driven pump for a rebuilt unit.
>=3B
>=3B After install= ing the rebuilt pump the engine tested fine on the ground and fine in the a= ir on a subsequent cross country trip. Approximately 2.1 hours of flying ti= me later the exact same symptoms returned...erratic fuel flow readings foll= owed closely by engine surge.
>=3B
>=3B I am now at a loss as to= what I should now look for. Could my problem be due to air somehow being i= ntroduced into my fuel flow? Should I be looking at my fuel selector as a p= ossible culprit? If so how would I test that possibility?
>=3B
>= =3B Any and all suggestions would be most appreciated.
>=3B
>=3B= Sent from my iPad
>=3B Berni Breen
>=3B Bbreen@cableone.net
&= gt=3B --
>=3B For archives and unsub http://mail.lancaironline.net:81/= lists/lml/List.html
= --_86a4d6c9-7af0-4740-8c8c-2a7f00a2242a_--