Mailing List flyrotary@lancaironline.net Message #57780
From: Tracy <rwstracy@gmail.com>
Subject: Re: [FlyRotary] Re: Mixture graph on EM-2
Date: Wed, 11 Apr 2012 21:15:09 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Bill,
      My cabin in Colorado is off-grid and I have no means to work on electronics out here so it will be May 8th before I can look at it.

Tracy

Sent from my iPad

On Apr 11, 2012, at 5:48 PM, "Bill Bradburry" <bbradburry@bellsouth.net> wrote:

Tracy,

 

The mixture function was working fine last June.  My mother in law fell and airplane stuff went by the way side until I was going to fly it last January.  That is when the mixture graph went south (north actually since it went up :>))

 

I will trace out the wire and ensure that it does in fact go to P2-8, but it looks like I will need to send it in.  Do you have to return from Colorado before it can be repaired?

 

B2

 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy
Sent: Wednesday, April 11, 2012 2:04 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Mixture graph on EM-2

 

Two possibilities:

1.  The EM2 is not working on the mixture function

2.   There is a miswire and the O2 input is not really connected where you think it is.

 

Only you are in a position to find out which it is.

 

Tracy

Sent from my iPad


On Apr 11, 2012, at 1:41 PM, "Bill Bradburry" <bbradburry@bellsouth.net> wrote:

Tracy,

 

Yesterday when I taxied the plane around to the hangar from the paint shop, the mixture graph was maxed out.  Today, the mixture graph is in the center (8 of 16 bars lit) with the engine not running.  I removed the O2 sensor so it was not grounded, no change, I disconnected the wire to the O2 sensor, no change, I then hooked up a wire from the sensor input to ground, no change!

 

New update:  Today with the sensor input grounded and the mixture bar at midscale, I turned on the fuel pump.  The fuel pressure went to 40 lbs, the fuel bar graph went to 2 bars above mid-scale, and the mixture graph pegged out at the top.  This happened with the mixture input grounded. All of the other indications looked normal.  I think this means there is an internal problem with the EM-2.  Are there other tests that you recommend?

 

Thank you,


Bill B

 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy
Sent: Tuesday, April 10, 2012 1:07 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Mixture graph on EM-2

 

Hi Bill,

First, be aware that O2 sensors do not work properly when cold so the reading means nothing when the engine is not running.

 

Try this test:    Connect the o2 sensor connection to ground and see what the monitor indicates.   It should be at minimum or no reading at all.   Or,  you could start the engine and see what happens.   Tell me what happens.

 

Tracy

Sent from my iPad


On Apr 10, 2012, at 11:23 AM, "Bill Bradburry" <bbradburry@bellsouth.net> wrote:

Hi Tracy,

 

I talked with you several weeks ago about my mixture graph going to max and staying there.  I just got the plane out of the paint shop and started trying to look at the problem. 

 

The graph stays maxed out and stays there when the power is turned on.  It is not affected by removing the O2 sensor from the exhaust so that it is not grounded.  This is all when the engine is not running and is cold.  What are the failure modes that could cause this?  I don’t think that it is coming from the sensor since it is the same when it is cold and ungrounded.

 

I know you mentioned bad grounds before, but I can find nothing wrong with grounds.  Everything else works that I know of.

 

Ideas please!

 

Bill B

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