X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 22 Sep 2014 08:59:24 -0400 Message-ID: X-Original-Return-Path: Received: from [63.230.26.161] (HELO exchange.arilabs.net) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 7159654 for lml@lancaironline.net; Mon, 22 Sep 2014 08:02:17 -0400 Received-SPF: none receiver=logan.com; client-ip=63.230.26.161; envelope-from=kevin@arilabs.net Received: from exchange.arilabs.net ([10.100.100.1]) by exchange.arilabs.net ([10.100.100.1]) with mapi; Mon, 22 Sep 2014 06:01:43 -0600 From: Kevin Stallard X-Original-To: "lml@lancaironline.net" X-Original-Date: Mon, 22 Sep 2014 06:01:20 -0600 Subject: Mechanical Fuel Pump Oddities Thread-Topic: Mechanical Fuel Pump Oddities Thread-Index: AQHP1lz5E3oAzIXKM06obAVEU01MXg== X-Original-Message-ID: <779FE3D761D7B741813E300858A248CF010CC3AAB3B9@exchange.arilabs.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Hi All, Recently (within the last couple of moths) as I climb past 8,500ft, my fuel= pressure becomes unstable. It drops and rises, from 13 to 14 PSI down belo= w 10 and then back up again. This, of course, has a noticeable effect on en= gine power (it drops and then comes back). By the time I get to 8500ft, I've already done the big pull and am running = LOP. If I turn on the electric fuel pump, and re-lean, everything stabilize= s. If I don't use the electric fuel pump and deal with the drop and surges in = power up to say 12,500ft, level off and begin to cruz, the fuel pressure st= abilizes to around 11 to 12 psi and the drops and surges in power stop. It's an IO-550N and tach time is north of 250 hours. Ideas? Thanks Kevin