X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf25aec.mail.bellsouth.net ([205.152.59.73] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1056649 for flyrotary@lancaironline.net; Mon, 03 Apr 2006 06:52:12 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.73; envelope-from=atlasyts@bellsouth.net Received: from ibm69aec.bellsouth.net ([65.11.149.236]) by imf25aec.mail.bellsouth.net with ESMTP id <20060403105121.NALM12116.imf25aec.mail.bellsouth.net@ibm69aec.bellsouth.net> for ; Mon, 3 Apr 2006 06:51:21 -0400 Received: from [192.168.0.100] (really [65.11.149.236]) by ibm69aec.bellsouth.net with ESMTP id <20060403105121.KAJC15586.ibm69aec.bellsouth.net@[192.168.0.100]> for ; Mon, 3 Apr 2006 06:51:21 -0400 Mime-Version: 1.0 (Apple Message framework v746.3) In-Reply-To: References: Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <7F49E69B-4D76-4785-B553-A95508BD8AC2@bellsouth.net> Content-Transfer-Encoding: 7bit From: Bulent Aliev Subject: Re: [FlyRotary] Re: Erratic mixture Date: Mon, 3 Apr 2006 06:51:53 -0400 To: "Rotary motors in aircraft" X-Mailer: Apple Mail (2.746.3) On Apr 3, 2006, at 1:27 AM, Bob White wrote: > On Sun, 2 Apr 2006 21:12:18 -0400 > Bulent Aliev wrote: > >> I have been trying to figure out why I'm having such a hard time >> tuning the engine. The other day we ran the plane on the long taxiway >> and it did not sound stable. We had occasional pops and the mixture >> kept going too rich or too lean. >> Today I was thinking if it has something to do with the fuel pressure >> regulator being controlled by the manifold pressure. As the MP >> varies, the FPR changes the fuel pressure. So the computer is trying >> to compensate the injector output for manifold pressure, but the fuel >> pressure is changing at the same time. I have seen the FP changing >> from 35 psi at low RPM to 50 psi at high boost? >> I wander if I should set the FPR at one value and let the EC2 take >> care of the rest? >> >> Buly >> Resealing the oil pan/engine mount to cure oil leak >> Welding a tiny leak in the radiator >> > > Hi Buly, > > I wonder if you have instability in your MP readings. If the MP seen > by the EC2 and the fuel pressure regulator is unstable because of > pressure waves in the plenum (or whatever) you could see erratic > changes > in the mixture. Do you have a restriction in the line to the MP > port on > your intake? If not, you might try adding one. Or, can you put the > tap > for the MP in a different location? > > Bob W. > Hi Bob, I made the hole in the plenum very small. The erratic behavior starts above 35" of MP pressure. Buly