X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.3.7) with ESMTP id 4324086 for flyrotary@lancaironline.net; Mon, 24 May 2010 09:25:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=XJBoL1f5z3etUdR3EmbNHXFie2oYvtf87KacKPijUJE= c=1 sm=0 a=81wLIGtB8b0A:10 a=ood2b7iyd8MA:10 a=Er6hwA6a1l4K/FyzC6NN7w==:17 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=ekHE3smAAAAA:20 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=AacmUTCEptJhBq0n3KcA:9 a=6lklv-Hn6F18Lq4BjQQA:7 a=O7cKgIYALFWf8DsjzY8zPTZZzXwA:4 a=CjuIK1q_8ugA:10 a=1vhyWl4Y8LcA:10 a=EzXvWhQp4_cA:10 a=SSmOFEACAAAA:8 a=J-XTuLPuubjJ93WW0x4A:9 a=5DdixGPDwDBV88vMA6IA:7 a=r7NLN-3o36Z0cacFPnGxUemH7eYA:4 a=Er6hwA6a1l4K/FyzC6NN7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 75.181.123.159 Received: from [75.181.123.159] ([75.181.123.159:2780] helo=computername) by cdptpa-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id E9/AA-02347-02E7AFB4; Mon, 24 May 2010 13:24:49 +0000 From: "Ed Anderson" Message-ID: To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Emailing: fuel system 002 Date: Mon, 24 May 2010 09:24:28 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0030_01CAFB22.E8D89B90" X-Mailer: Microsoft Office Outlook, Build 11.0.5510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5931 In-Reply-To: Thread-Index: Acr7MHmQLi7vkQOXRDe3AxezatazHQAElTeQ This is a multi-part message in MIME format. ------=_NextPart_000_0030_01CAFB22.E8D89B90 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sounds like you are on the right track, John. Yes, "T"ing the high pressure return with your low pressure return could potentially end up sending some fuel toward your Webber. Idle rpm is when the fuel injector pressure regulator is dumping the most fuel back into the return line - and it dumping a lot. At idle, there is minimum fuel being injected into the engine, so therefore, the EFI pressure regulator has to release the maximum amount of fuel back into the return line to keep the pressure regulated to what ever value you have set it. At WOT there is much less fuel being returned as more of it is being consumed by the engine and there less fuel is need to be released by the Pressure regulator to maintain pressure. Now I see you have a pressure regulator in you Webber line, don't know what it is set for - but as I recall it only takes a few PSI of fuel pressure to feed a carburetor float bowl - so with the EFI pressure regulator dumping a whole lot of fuel into the return line - it may well raise the pressure to a couple of psi in that line which pushes back to the carb float bowl thereby providing an unintended path for fuel to the Carb when the injectors are operating. Could possibly be a faulty low pressure fuel regulator that is letting some fuel seep - I would think that if it sees no fuel pressure from your low pressure pump it should have its port to the return line closed off which theoretically should keep fuel from backing up through the return line to the Carb. But, one of two things could be happening there - you simply could have a leak in the low pressure regulator or if there is no fuel pressure from the low pressure pump - perhaps the return port on the low pressure fuel regulator remains Open. In any case, looks like you have nailed the source of the problem down. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of John Sent: Monday, May 24, 2010 7:01 AM To: Rotary motors in aircraft Subject: [FlyRotary] Emailing: fuel system 002 here is a picture of the fuel system, tried the scanner and the file was to large. Fuel must be seeping back thru the L.P. regulator and fuel pumps. JohnD To soon old, to late smart, which comes a bit at a time ------=_NextPart_000_0030_01CAFB22.E8D89B90 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Sounds like you are on the right = track, John.  Yes, “T”ing the high pressure return with your = low pressure return could potentially end up sending some fuel toward your Webber.   Idle rpm  is when the fuel injector pressure = regulator is dumping the most fuel back into the return line – and it = dumping a lot.  At idle, there is minimum fuel being injected into the engine, so = therefore, the EFI pressure regulator has to release the maximum amount of fuel = back into the return line to keep the pressure regulated to what ever value you = have set it.  At WOT there is much less fuel being returned as more of it is = being consumed by the engine and there less fuel is need to be released by the = Pressure regulator to maintain pressure. 

 

Now I see you have a pressure = regulator in you Webber line, don’t know what it is set for – but as I = recall it only takes a few PSI of fuel pressure to feed a carburetor float bowl = – so with the EFI pressure regulator dumping a whole lot of fuel into the = return line – it may well raise the pressure to a couple of psi in that = line which pushes back to the carb float bowl thereby providing an unintended = path for fuel to the Carb when the injectors are operating.  Could = possibly be a faulty low pressure fuel regulator that is letting some fuel seep = – I would think that if it sees no fuel pressure from your low pressure pump it = should have its port to the return line closed off which theoretically should = keep fuel from backing up through the return line to the Carb. But, one of = two things could be happening there – you simply could have a leak in = the low pressure regulator or if there is no fuel pressure from the low pressure = pump – perhaps the return port on the low pressure fuel regulator remains = Open.

 

In any case, looks like you have = nailed the source of the problem down.

 

Ed  =

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of John
Sent: Monday, May 24, = 2010 7:01 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] = Emailing: fuel system 002

 

here is a picture of the fuel system, tried the = scanner and the file was to large.  Fuel must be seeping back thru the L.P. = regulator and fuel pumps.  JohnD      To soon old, = to late smart, which comes a bit at a time

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