Return-Path: Received: from mail.viclink.com ([206.212.237.11] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 726114 for flyrotary@lancaironline.net; Sat, 12 Feb 2005 09:32:20 -0500 Received-SPF: none receiver=logan.com; client-ip=206.212.237.11; envelope-from=pjmick@mail.viclink.com Received: from mail.viclink.com (pt67-76.onlinemac.com [198.92.67.76]) (authenticated bits=0) by mail.viclink.com (8.13.2/8.13.2) with ESMTP id j1CEVW2n080512 for ; Sat, 12 Feb 2005 06:31:33 -0800 (PST) Message-ID: <420E12AF.5040306@mail.viclink.com> Date: Sat, 12 Feb 2005 06:29:03 -0800 From: Perry Mick User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Fly Rotary Subject: Vapor Lock Content-Type: multipart/alternative; boundary="------------040601070803000209010604" --------------040601070803000209010604 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Ed Anderson wrote: I believe someone, Jim S?, mentioned that if there is a vapor lock problem it is almost certainly occurring before the EFI pumps, and I agree. Many EFI automobiles today are using a "no-return" fuel system. But in those systems the fuel system is pressurized to high pressure all the way from the in-tank pump to the engine - so with 20-40 psi fuel pressure in the lines it considerably reduces the probability of vapor forming. Although if you heat any fuel sufficiently (like a line next to an exhaust header pipe) you can get vapor bubbles. In Paul's case, I am not certain it was vapor lock since he mentioned he found the his header tank cool to the touch. Certainly not a definitive temperature sensor - but a reasonable one. Certainly not to be discounted as a possible source of the problem and it possibility needs to be confirmed or eliminated. Ed, this was my experience, the vapor lock was in the main line between the main tank and the sump tank, not in the EFI system. This caused the sump tank to drain dry, fortunately on the ground. I think this could have happened to Paul - because he had been running his engine on the ground and generating a lot of heat, a vapor lock formed in the low pressure input side of his sump tank such that it wasn't filling with fuel. He suffered fuel exhaustion because the sump tank ran dry. He said his tank is just 1.5 gallons, mine is 1 gallon. Just a theory... Perry --------------040601070803000209010604 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit

Ed Anderson wrote:

I believe someone, Jim S?, mentioned that if there is a vapor lock problem it is almost certainly occurring before the EFI pumps, and I agree. Many EFI automobiles today are using a "no-return" fuel system. But in those systems the fuel system is pressurized to high pressure all the way from the in-tank pump to the engine - so with 20-40 psi fuel pressure in the lines it considerably reduces the probability of vapor forming. Although if you heat any fuel sufficiently (like a line next to an exhaust header pipe) you can get vapor bubbles.

In Paul's case, I am not certain it was vapor lock since he mentioned he found the his header tank cool to the touch. Certainly not a definitive temperature sensor - but a reasonable one. Certainly not to be discounted as a possible source of the problem and it possibility needs to be confirmed or eliminated.

Ed, this was my experience, the vapor lock was in the main line between the main tank and the sump tank, not in the EFI system. This caused the sump tank to drain dry, fortunately on the ground. I think this could have happened to Paul - because he had been running his engine on the ground and generating a lot of heat, a vapor lock formed in the low pressure input side of his sump tank such that it wasn't filling with fuel. He suffered fuel exhaustion because the sump tank ran dry. He said his tank is just 1.5 gallons, mine is 1 gallon. Just a theory...

Perry

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