Return-Path: <13brv3@bellsouth.net> Received: from imf17aec.mail.bellsouth.net ([205.152.59.65] verified) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3141525 for flyrotary@lancaironline.net; Thu, 01 Apr 2004 21:52:56 -0500 Received: from rad ([65.0.128.69]) by imf17aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040402025255.ITJS1746.imf17aec.mail.bellsouth.net@rad> for ; Thu, 1 Apr 2004 21:52:55 -0500 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Rusty's O2 / EM2 problems. Date: Thu, 1 Apr 2004 20:55:01 -0600 Message-ID: <012101c4185d$e472f220$6001a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0122_01C4182B.99D88220" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 In-Reply-To: Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_0122_01C4182B.99D88220 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Considering that my O2 sensor exhibits similar behavior as yours = and I also measure downstream EGT temps (after turbo) right beside the O2 = sensor and only see temps in the 700F range, I can't help but think that maybe = the low temps are possibly the cause of the problem. =20 =20 My EGT probes are about 10 inches from the port, and the O2 sensor is = about 40 inches farther downstream. I'm confident that I can get the temps to 800F at the O2 sensor, but I may not have the day I installed the = sensor. I was seeing temps in the 1000 to 1100 range at low rpms, but the other = day, when tied down, I was reaching 1600's at full throttle. That was with = the old sensor though. I'll probably be doing some more running tomorrow, = so we'll see what I get. I also have the old mixture gauge installed as = well as the EM-2. =20 =20 =20 Here is a site that explains O2 sensors- http://www.ngkspark.com.au/tech_info_oxygen_sensors_index.htm =20 Here is an excerpt from that site: =20 How To Test Oxygen Sensors? Using an appropriate connecting device, connect the sensor output to = your oscilloscope; do not disconnect the sensor from the ECU. Run the engine = at approximately 2000 rpm. A properly functioning oxygen sensor will show a rapidly fluctuating output voltage between approximately 0.1 and 1.0 = volts. The time taken for the voltage to change from 0.1 V to 1.0 V (referred = to as the lean to rich response time) should be about 300 milliseconds. A = similar time should be measured when the voltage changes from 1.0 V to 0.1 V = (rich to lean response time).=20 If the sensor output is constant or the response time is too slow the = sensor should be changed.=20 =20 =20 Can anyone explain why the voltage is supposed to cycle between .1V and = 1.0V ? Tracy said the EM-2 doesn't do any averaging, but just captures the voltage in a snapshot when it's time to measure that channel. If that = was the case, it would seem that a "properly operating" sensor would cause = the EM-2 to be erratic. =20 =20 Hopefully, tomorrow's testing will reveal some more useful info. =20 =20 Rusty (looking to fly again this weekend) ------=_NextPart_000_0122_01C4182B.99D88220 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
        Considering that my O2 sensor exhibits similar behavior as = yours and=20 I also measure downstream EGT temps (after turbo) right beside the O2 = sensor and=20 only see temps in the 700F range, I can't help but think that maybe the = low=20 temps are possibly the cause of the problem.  
 
My EGT probes are about 10 inches from the = port, and the O2=20 sensor is about 40 inches farther downstream.  I'm = confident that=20 I can get the temps to 800F at the O2 sensor, but I may not have = the day I=20 installed the sensor.  I was seeing temps in the 1000 to 1100 range = at low rpms, but the other day, when tied down, I was reaching = 1600's at=20 full throttle.  That was with the old sensor though.  I'll = probably be=20 doing some more running tomorrow, so we'll see what I get.  I also = have the=20 old mixture gauge installed as well as the=20 EM-2.  
 
 
Here is a site that explains O2 = sensors-  ht= tp://www.ngkspark.com.au/tech_info_oxygen_sensors_index.htm
 
Here is an excerpt from that=20 site:
 
How To Test Oxygen = Sensors?

Using=20 an appropriate connecting device, connect the sensor output to your=20 oscilloscope; do not disconnect the sensor from the ECU. Run the engine = at=20 approximately 2000 rpm. A properly functioning oxygen sensor will show a = rapidly=20 fluctuating output voltage between approximately 0.1 and 1.0 volts. The = time=20 taken for the voltage to change from 0.1 V to 1.0 V (referred to as the = lean to=20 rich response time) should be about 300 milliseconds. A similar time = should be=20 measured when the voltage changes from 1.0 V to 0.1 V (rich to lean = response=20 time).

If the sensor output is constant or the response time is = too slow=20 the sensor should be changed.
 
 
Can anyone explain why the voltage is = supposed to cycle=20 between .1V and 1.0V ?  Tracy said the EM-2 doesn't do any = averaging, but=20 just captures the voltage in a snapshot when it's time to measure that=20 channel.  If that was the case, it would seem that a "properly = operating" sensor would cause the EM-2 to be erratic. =20
 
Hopefully, tomorrow's testing will reveal = some more=20 useful info. 
 
Rusty (looking to fly again this=20 weekend)
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