X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2.6) with ESMTP id 3070262 for flyrotary@lancaironline.net; Sun, 10 Aug 2008 19:36:35 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=alventures@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao102.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20080810233556.QWWN6684.fed1rmmtao102.cox.net@fed1rmimpo02.cox.net> for ; Sun, 10 Aug 2008 19:35:56 -0400 Received: from BigAl ([72.192.137.74]) by fed1rmimpo02.cox.net with bizsmtp id 0nbw1a00F1cVYgg04nbwoY; Sun, 10 Aug 2008 19:35:56 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Fuel pressure Date: Sun, 10 Aug 2008 16:37:06 -0800 Message-ID: <000001c8fb4a$61ab7f40$6401a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C8FB07.538AB040" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C8FB07.538AB040 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Tracy; =20 I'm glad you mentioned that. I was about to conclude that the problem = was incorrect data, not faulty regulator. I could not be sure that the = richer mixture I had connected with the first occurrence of higher fuel = pressure was cause and effect - I possible had not leaned again after climbing to = a higher altitude - then noticed the mixture and the higher pressure = reading. On the second occurrence I had not noted a mixture change. Flew for an = hour today (beautiful up and down the beach:-)) and the fuel pressure was = always where it should be. The sensor offset was also what it should be. So = until it happens again . .=20 =20 Are you going to replace the VDO sender? =20 Al G =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Crook Sent: Saturday, August 09, 2008 3:57 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Fuel pressure =20 I am seeing some similar indications on fuel pressure (going higher) = myself but not a change in mixture. =20 I looked at the sensor offset in EM2 after landing (and relieving the pressure in fuel system) and it looks like the sensor is drifting = around. I reset the sensor offset and things went back to normal for awhile.=20 =20 VDO now has a warning on their senders to not use them on anything but = oil. Don't know if this has anything to do with it or not. My sender is = about 6 years old. =20 Tracy On Sat, Aug 9, 2008 at 3:32 PM, Al Gietzen wrote: Somewhere during my trip a few weeks ago, I had noted that the engine = seemes to be running a bit rich from where I had set it. I then noted that the fuel pressure was reading high - like about 48 -49 psi; and I have the regulator set for 40 psi at WOT. Not know what else to try, I switched = from pump 1 to pump 2. After a bit the pressure was back to normal; and = worked fine after that. =20 My thought later was that switching the pumps should have nothing to do = with it. The two pumps are in parallel, then the filter, then the pressure sensor, then the fuel rail with the regulator on the end, bypassing back = to the tank. =20 Last week on a short flight I noted the fuel pressure bar on the EM2 at = the max and blinking. The readout was 50 psi. I watched for a short while nothing changed; then switched pumps. Nothing changed right away, but = the pressure slowly returned to normal. Then running pump1, both pumps, or = pump 2 didn't make any difference. =20 I discussed with the expert at TWM (the maker of the pressure regulator) = and after some discussion, he was completely at a loss as to what could = cause the pressure regulator to act in that fashion. It is a MAP referenced regulator, and the MAP readout was as it should be. =20 I'm baffled. =20 Al =20 ------=_NextPart_000_0001_01C8FB07.538AB040 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Tracy;

 

I’m glad you mentioned = that.  I was about to conclude that the problem was incorrect data, not faulty regulator.  I could not be sure that the richer mixture I had = connected with the first occurrence of higher fuel pressure was cause and effect = – I possible had not leaned again after climbing to a higher altitude = – then noticed the mixture and the higher pressure reading.  On the = second occurrence I had not noted a mixture change.  Flew for an hour today = (beautiful up and down the beachJ) and the fuel pressure was always where it should be. =  The sensor offset was also what it should be. So until it happens again . . =

 

Are you going to replace the VDO = sender?

 

Al G

 

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Crook
Sent: Saturday, August = 09, 2008 3:57 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = Fuel pressure

 

I am seeing some similar indications on fuel = pressure (going higher) myself but not a change in mixture.

 

I looked at the sensor offset in EM2 after = landing (and relieving the pressure in fuel system) and it looks like the sensor = is drifting around.  I reset the sensor offset and things went back to = normal for awhile.

 

VDO now has a warning on their senders to not = use them on anything but oil.  Don't know if this has anything to do with it = or not.  My sender is about 6 years old.

 

Tracy

On Sat, Aug 9, 2008 at 3:32 PM, Al Gietzen = <ALVentures@cox.net> = wrote:

Somewhere during my trip a few weeks ago, I = had noted that the engine seemes to be running a bit rich from where I had = set it.  I then noted that the fuel pressure was reading high – = like about 48 -49 psi; and I have the regulator set for 40 psi at WOT. Not = know what else to try, I switched from pump 1 to pump 2. After a bit the pressure = was back to normal; and worked fine after that.

 

My thought later was that switching the = pumps should have nothing to do with it.  The two pumps are in parallel, = then the filter, then the pressure sensor, then the fuel rail with the = regulator on the end, bypassing back to the tank.

 

Last week on a short flight I noted the fuel pressure bar on the EM2 at the max and blinking. The readout was 50 psi. = I watched for a short while nothing changed; then switched pumps.  = Nothing changed right away, but the pressure slowly returned to normal. Then = running pump1, both pumps, or pump 2 didn't make any difference.

 

I discussed with the expert at TWM (the = maker of the pressure regulator) and after some discussion, he was completely at = a loss as to what could cause the pressure regulator to act in that = fashion.  It is a MAP referenced regulator, and the MAP readout was as it should = be.

 

I'm baffled.

 

Al

 

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