X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 01 Jun 2005 15:56:26 -0400 Message-ID: X-Original-Return-Path: Received: from systems3.net ([68.14.236.16] verified) by logan.com (CommuniGate Pro SMTP 4.3.4) with ESMTPS id 980783 for lml@lancaironline.net; Wed, 01 Jun 2005 13:58:21 -0400 Received-SPF: none receiver=logan.com; client-ip=68.14.236.16; envelope-from=cberland@systems3.net Received: from systems0d3b724 ([192.168.1.81]) by systems3.net (8.13.4/8.13.4/Debian-1) with SMTP id j51HvaXF017067 for ; Wed, 1 Jun 2005 10:57:36 -0700 X-Original-Message-ID: <005901c566d3$50c5f390$5101a8c0@systems0d3b724> From: "Craig Berland" X-Original-To: "Lancair Mail List" Subject: [LML] misfire X-Original-Date: Wed, 1 Jun 2005 10:56:57 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0056_01C56698.A15B8940" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_0056_01C56698.A15B8940 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Matt said: I had a problem on a flight on Saturday that I have never = had before. The plane is just out of annual. I made a one hour flight = at 25" x 2400 RPM. Approach asked me to descend relatively quickly. I = pulled the power back to about 21" x 2500 RPM and the engine started = running rough. I noticed the #4 EGT at zero. I pushed the MP back up = and it cleared up. I pulled the RPM down to about 2300 - 2400 and it = cleared up. Just leaning the mixture didn't solve the problem, nor did = richening the mixture. This was the first annual where I have NOT replaced the plugs. Instead, = an A&P just cleaned them (they are automotive Iridium plugs). I have electronic ignition and electronic injection. Was it a clogged = injector? Not likely, as it cleared up at higher MPs and lower RPMs. = Was it a spark problem? Not impossible, but it would have had to kill = both plugs. Were the plugs fouled? Not impossible, as #4 is my richest = cylinder. But the problem happened later when I tested it, after I had = been running for 20 minutes LOP. Unfortunately, I tried to get it to happen again on the ground and, of = course, it won't repeat itself (at about 20" and 2400 RPM). Any thoughts? I'm going out to decowl the plane and inspect the plugs, = but I'd appreciate any thoughts as to what to look for. Matt, I don't think it is a bad plug since it is easier to fire a plug = at 21 MAP than it is at 25 MAP. If you have run the engine at this = exact MAP/RPM before without a problem, then I would look for a sensor = or connection that was disturbed during the annual. If this is a newly = tested/run MAP/RPM then I would check the MAP tables for the EFI. It = sounds like the computer was commanding the engine to not run. Why, I = don't really have a good idea. What is puzzling is just one cylinder = being affected. I assume it idles OK. ??? If so then the EFI injectors = are most likely OK. Craig Berland ------=_NextPart_000_0056_01C56698.A15B8940 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Matt=20 said: I had a problem on a flight on Saturday that I have = never had=20 before. The plane is just out of annual. I made a one hour = flight at=20 25" x 2400 RPM. Approach asked me to descend relatively=20 quickly. I pulled the power back to about 21" x 2500 RPM and = the=20 engine started running rough. I noticed the #4 EGT at zero. = I pushed=20 the MP back up and it cleared up. I pulled the RPM down to about = 2300 -=20 2400 and it cleared up. Just leaning the mixture didn't solve the = problem,=20 nor did richening the mixture.

This was the first annual = where I have=20 NOT replaced the plugs. Instead, an A&P just cleaned them = (they=20 are automotive Iridium plugs).

I have electronic ignition and = electronic injection. Was it a clogged injector? Not likely, = as it=20 cleared up at higher MPs and lower RPMs. Was it a spark = problem? Not=20 impossible, but it would have had to kill both plugs. Were the = plugs=20 fouled? Not impossible, as #4 is my richest cylinder. But = the=20 problem happened later when I tested it, after I had been running for 20 = minutes=20 LOP.

Unfortunately, I tried to get = it to=20 happen again on the ground and, of course, it won't repeat itself (at = about 20"=20 and 2400 RPM).

Any thoughts? I'm going = out to=20 decowl the plane and inspect the plugs, but I'd appreciate any thoughts = as to=20 what to look for.

Matt, I don't think it is a bad = plug since=20 it is easier to fire a plug at 21 MAP than it is at 25 MAP. If you = have=20 run the engine at this exact MAP/RPM before without a problem, then I = would look=20 for a sensor or connection that was disturbed during the = annual. If=20 this is a newly tested/run MAP/RPM then I would check the MAP tables for = the=20 EFI. It sounds like the computer was commanding the engine to not run. = Why, I=20 don't really have a good idea. What is puzzling is just one cylinder = being=20 affected. I assume it idles OK. ??? If so then the EFI injectors = are most=20 likely OK.

Craig Berland

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