Mailing List flyrotary@lancaironline.net Message #13548
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: Nice to Have Re: ECU oxygen sensor
Date: Tue, 7 Dec 2004 11:46:01 -0600
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
    I thought that you had the EM2, but sometimes it's hard to keep track of everybody's projects.... well, except John's & Rusty's :-)
The EM2 really is the better way to go.
 
Todd 
 
 
Hey, some of us don't have poopy diapers to change, so we have time for the list :-)  
 
As for your EM-2 air/fuel display, does your engine run well at the mid-scale reading?  My engine used to run at mid-scale on the old mixture monitor gauge, but I have to be at about 8 bars on the EM-2.  Tracy says his runs fine at mid-scale on the EM-2, and of course I believe him, but I've never been able to explain this.  
 
I did some testing with a variable voltage source, and these are my notes:
 

3-30-04

 

Checked the old mixture gauge, and found that it lights the first bar at .33V, the 5th bar (mid scale) at .86V, and the last bar at 1.4V.  The EM-2 lights a bar every .1V, with full scale at 1.0V.  This is supposed to be the way O2 sensors work, but my old gauge worked fine on the previous engine configuration. 
 
I ran the old gauge with the EM-2 for a while, and just accepted that my new "normal" reading is 8 bars.  
 
There's a possibility that my old mixture monitor gauge was just wrong, but I find it odd that mid-scale is right where the engine wanted to be.  Since you have one of these, and have the ability to fashion a variable voltage source, would you test yours to see if the mid-scale reading is similar to the .86V I found with mine?   Since that gauge has colored markings, perhaps the manufacturer centered the green range on .86V for a reason.  I've thought about scaling my EM-2 down to make midrange "normal".   It's just one of those things that festers in the back of my brain and bothers me. 
 
Cheers,
Rusty (debating flaperons on the Kolb list)
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