X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 06 Jul 2012 10:50:57 -0400 Message-ID: X-Original-Return-Path: Received: from mail-pb0-f52.google.com ([209.85.160.52] verified) by logan.com (CommuniGate Pro SMTP 5.4.6) with ESMTPS id 5640565 for lml@lancaironline.net; Fri, 06 Jul 2012 10:44:41 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.52; envelope-from=pjdmiller@gmail.com Received: by pbbro8 with SMTP id ro8so14435923pbb.25 for ; Fri, 06 Jul 2012 07:44:05 -0700 (PDT) Received: by 10.68.189.199 with SMTP id gk7mr6330882pbc.25.1341585845076; Fri, 06 Jul 2012 07:44:05 -0700 (PDT) X-Original-Return-Path: Received: from [10.162.89.22] (s207-216-73-83.bc.hsia.telus.net. [207.216.73.83]) by mx.google.com with ESMTPS id b10sm22002774pbr.46.2012.07.06.07.44.03 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 06 Jul 2012 07:44:04 -0700 (PDT) From: Paul Miller Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-2-353901775 Subject: Re: [LML] Re: Fuel Pressure Problems X-Original-Date: Fri, 6 Jul 2012 07:43:58 -0700 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1084) --Apple-Mail-2-353901775 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 I don't think pressure on the Continental is used for inflight diagnosis = although they are used during setup and confirmed with takeoff flows. I = don't even have inflight fuel pressure readings on the Legacy. Cessna = previously used pressures as a proxy for flow but that was wrong when = higher pressures turned out to be injector blockage that resulted = actually in lower flows. Then, flows were introduced as the primary = means to manage the big TCMs. So, where is the transducer for pressure = and what are the flows at takeoff and cruise and did they change? = Because a huge amount of fuel in the Continental system is returned to = the tank, pressure may not be a factor. And, from experience, check the = cowling and other areas for blue staining and flag any aroma of avgas in = the cockpit as a show stopper (those flows were actually higher than = normal because of leaks). Paul Legacy 550N Calgary On 2012-07-05, at 9:36 PM, Robert R Pastusek wrote: > Alan, > How about a blockage in the fuel system? I mention this because we = just found a disintegrated fuel flow impeller (a wee tiny thing to start = with) that was blocking the fuel line on a TSIO-550. The owner says the = fuel flow was =93indicating=94 even when the engine would barely run, so = apparently there was enough impeller in the sensor to at least give a = reading, but most of it was down-stream in the fuel system. (the engine = did not run well at all=85) > =20 > Bob > =20 > From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Alan Crawford > Sent: Thursday, July 05, 2012 3:45 PM > To: lml@lancaironline.net > Subject: [LML] Fuel Pressure Problems > =20 > Just started having a change in fuel pressure at cruise. I have a = Legacy ... 550N ... been cruising 40 to 60 degrees lean of peak with no = problem, with fuel pressure above 8.2 psi. Depending on altitude 2500 = rpm - 2300 rpm ... 11.5 to 11.8 gph ... > =20 > The last few flights I can not get 40 degrees lean of peak at any = altitude without the fuel pressure dropping below 8.0 psi ... even if I = turn on the fuel pump to low =3D 9, 500 - 11,500 - 12,500 ???? > =20 > any ideas on what is going on???? Takeoff fuel pressure is 28.0 psi = .... =20 > =20 > Thanks ...=20 > Alan Crawford > Lake Buchanan, Texas > Lancair Legacy=20 > =20 --Apple-Mail-2-353901775 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 I = don't think pressure on the Continental is used for inflight diagnosis = although they are used during setup and confirmed with takeoff flows. =  I don't even have inflight fuel pressure readings on the Legacy. =    Cessna previously used pressures as a proxy for flow but = that was wrong when higher pressures turned out to be injector blockage = that resulted actually in lower flows.   Then, flows were = introduced as the primary means to manage the big TCMs.  So, where = is the transducer for pressure and what are the flows at takeoff and = cruise and did they change?  Because a huge amount of fuel in the = Continental system is returned to the tank, pressure may not be a = factor.  And, from experience, check the cowling and other areas = for blue staining and flag any aroma of avgas in the cockpit as a show = stopper (those flows were actually higher than normal because of = leaks).

Paul
Legacy = 550N
Calgary
On 2012-07-05, at 9:36 PM, Robert R = Pastusek wrote:

Alan,
How about a blockage in the fuel = system? I mention this because we just found a disintegrated fuel flow = impeller (a wee tiny thing to start with) that was blocking the fuel = line on a TSIO-550. The owner says the fuel flow was =93indicating=94 = even when the engine would barely run, so apparently there was enough = impeller in the sensor to at least give a reading, but most of it was = down-stream in the fuel system. (the engine did not run well at = all=85)
From: Lancair Mailing List = [mailto:lml@lancaironline.net] On Behalf Of Alan = Crawford
Sent: Thursday, July 05, 2012 = 3:45 PM
To:  [LML] Fuel Pressure = Problems
Just started having a = change in fuel pressure at cruise.  I have a Legacy ... 550N ... = been cruising 40 to 60 degrees lean of peak with no problem, with fuel = pressure above 8.2 psi. Depending on altitude 2500 rpm - 2300 rpm ... = 11.5 to 11.8 gph ...
 
The last few flights I can not get 40 degrees lean = of peak at any altitude without the fuel pressure dropping below 8.0 psi = ... even if I turn on the fuel pump to low =3D 9, 500 - 11,500 - = 12,500 ????
 
any ideas on what is going on???? Takeoff fuel = pressure is 28.0 psi = ....  
 
Thanks = ... 
Alan = Crawford
Lake Buchanan, = Texas
Lancair = Legacy