X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop: No license found, only first 5 messages were scanned Return-Path: Received: from [69.171.58.236] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WEBUSER 5.1c.1) with HTTP id 1191465 for lml@lancaironline.net; Tue, 20 Jun 2006 23:07:58 -0400 From: "Marvin Kaye" Subject: Re: [LML] Re: Crash follow-up Dave Hickman To: lml X-Mailer: CommuniGate Pro WebUser v5.1c.1 Date: Tue, 20 Jun 2006 23:07:58 -0400 Message-ID: In-Reply-To: <51f.acd958.31c9bf0b@aol.com> References: <51f.acd958.31c9bf0b@aol.com> MIME-Version: 1.0 Content-Type: text/plain;charset="iso-8859-1";format="flowed" Content-Transfer-Encoding: 8bit Posted for Sky2high@aol.com: Pat, Interesting....... There are at least two ways to create an over rich mixture. One, of course, is the way you mentioned - a system malfunction that supplies too much fuel for the selected operation mode. In the case of a take-off, the throttle is positioned wide open (WOT), where special enrichening is used and imparting its full effect when max RPM is reached. Closing the throttle somewhat takes the system out of the super-rich mode. Note that the problem would not be detected during run-up since that is not usually accomplished at WOT. Another way is to partially restrict the induction air while the throttle body is expecting more. Suppose an interconnecting induction hose partially collapses, a bird built a nest in the filter compartment and/or the filter stops supplying enough air where alternate air is not automatically supplied, etc. Again, this condition would not be detected at any partial throttle setting such as run-up but would definitely show up during take-off when operating at WOT and max RPM. Keeping your mind on the paragraph just above, consider the setup where filtered alternate air is used for take-off by manually closing off unfiltered ram air. Consider that the filter is the highly regarded K&N. Let's say the filter was recently cleaned and re-oiled. Let's further add that too much oil was used. Finally, after some use, the dirt and oil managed to close off the filter. OK, what stupid trick did I pull that made me think of an over oiled filter or restricted induction air? Well, my fancy computer controlled motorcycle engine is run by sensing coolant temperature, OAT, MAP, RPM, exhaust O2 and throttle position. It is equipped with a pricey polished one of a kind ram air induction port fed thru a rather small K&N filter. About a week after I cleaned and re-oiled the filter, the bike began to run like excrement - black smoke, fits and starts, sputtering, etc. Removing most of the oil from the filter restored the pulsating power of 110 ci crammed into 2 jugs.... Ahhh.... Anyway, the throttle position sensor led the computer to expect just so much air - but no, the air wasn't there and the mixture became too rich. BTW, since no sensor failed its reasonable range test, the computer did not think anything was wrong. Remember - Spark, Gas and Air are required for a burn. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Abnegate Exigencies!