X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Thu, 26 Nov 2009 09:04:58 -0500 Message-ID: X-Original-Return-Path: Received: from smtp1.av-mx.com ([137.118.16.57] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 3991524 for lml@lancaironline.net; Wed, 25 Nov 2009 21:42:39 -0500 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.57; envelope-from=pinetownd@volcano.net Received: from DennisPC (65-166-101-81.dsl.volcano.net [65.166.101.81]) (Authenticated sender: pinetownd@volcano.net) by smtp1.av-mx.com (Postfix) with ESMTP id 48B6E290C71 for ; Wed, 25 Nov 2009 21:42:03 -0500 (EST) X-Original-Message-ID: <49FC715F12804B568F870F96E31AC94B@DennisPC> From: "Dennis Johnson" X-Original-To: "Lancair Mailing List" Subject: Re: Fuel Pressure question X-Original-Date: Wed, 25 Nov 2009 18:42:04 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0144_01CA6DFE.FB66A790" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6001.18000 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 This is a multi-part message in MIME format. ------=_NextPart_000_0144_01CA6DFE.FB66A790 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable I have a Legacy with an IO-550 engine. I installed the fuel pressure = sensor to measure metered pressure for three reasons: 1. That's what the Chelton installation manual suggested. 2. That's what seemed to me to be the most diagnostic fuel pressure, = since that's what the fuel injectors are seeing. 3. The SID97-3 fuel setup procedure uses metered fuel pressure at full = power and unmetered fuel pressure at idle. I think the full power = pressure is more valuable than the unmetered idle fuel pressure. =20 Every fuel pressure spec I've seen in the TCM engine manuals, as well as = SID97-3, includes metered and unmetered pressures. However, to fully = comply with SID97-3 fuel system setup requires pressure gauges on both = the unmetered and metered pressures. It says to set the unmetered fuel = pressure at idle and the metered fuel pressure at full power. It's in a = footnote, which says: FULL POWER unmetered fuel pump pressure limits are provided for = reference only. Use metered fuel pressure specifications for adjustments at full = power. By the way, my metered fuel pressure at idle 1,000 RPM is 4 PSI. Dennis Legacy ------=_NextPart_000_0144_01CA6DFE.FB66A790 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

I have a Legacy with an IO-550 engine. I installed the fuel = pressure=20 sensor to measure metered pressure for three reasons:

1. That's what the Chelton installation manual = suggested.

2. That's what seemed to me to be the most diagnostic = fuel=20 pressure, since that's what the fuel injectors are seeing.

3. The SID97-3 fuel setup procedure uses metered fuel = pressure at=20 full power and unmetered fuel pressure at idle. I think the full = power=20 pressure is more valuable than the unmetered idle fuel pressure. =

Every fuel pressure spec I've seen in the TCM engine manuals, as = well as=20 SID97-3, includes metered and unmetered pressures. = However, to=20 fully comply with SID97-3 fuel system setup requires pressure gauges on = both the=20 unmetered and metered pressures. It says to set the unmetered fuel = pressure at idle and the metered fuel pressure at full power. It's = in a=20 footnote, which says:

FULL POWER unmetered fuel pump pressure limits = are=20 provided for reference only.
Use metered fuel = pressure=20 specifications for adjustments at full power.

By the way, my metered fuel pressure at idle 1,000 RPM is 4 = PSI.

Dennis

Legacy

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