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Date: Sun, 19 Jul 2009 17:42:09 -0600
From: Bob White <bob@bob-white.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] More EC2 Tuning - Less progress - need help/ideas
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Hi Mike,

From what I seem to remember about engine operation (I'm far from an
expert), the surging sounds like an over rich mixture, and the knocking
and banging would indicate the timing was too far advanced.  The EC2
has a timing adjustment in Mode 8.  Can you put a timing light on the
engine and compare timing on the B controller with timing on the A
controller?  If the timing is off, that should be fixed first.  Then if
the surging is still a problem, try adjusting the mixture to see if it
improves.  

Bob W.

On Sun, 19 Jul 2009 16:52:27 -0600
Mike Fontenot <mikef@apexconsultingservices.com> wrote:

> Hi all,
> 
> Hope the summer has been going well for the rest of you. I had a detour in
> my EC2 tuning, but am back at it.
> 
> Summary: EC2 on A controller has the engine surging at just about all RPMs I
> could manage to attain. Kind of a "rummm.... rummmm..... rummm..".  I could
> only get the RPMs up to around 1800 (out of a 5600 max) and the engine is
> knocking and banging, and even making a 'pffffut' kind of noise. Sounded
> like air or something.  Maybe coolant spewing out, because at the end of my
> session today I did find coolant on the ground, from my overflow tank.  Not
> smooth at all and I was afraid of losing parts! off the engine! Really
> rough, never develops much power.
> 
> However, when I flip to the B controller it runs great. Very smooth,
> responsive, no surging at all. I can run the engine through the full range
> of RPM.  I noticed that a MAP of 22 is at about 5200 RPM.  In may I got to
> around 4700 at a MAP of 22. I noted this because I was going to start with
> Mode 3 programming (at MAP 22). I could not get anywhere near MAP 22.
> 
> Background: I had been making progress getting the EC2 tuned in May and
> early June. The A controller worked fine but the B controller would not
> function and the engine would die. TC had me remove the EC2 and send it back
> to him. He did find problems with the B side and repaired it. And set all
> the programming back to the defaults.
> 
> I have dual crank position sensors, one dedicated to A controller, and one
> dedicated to the B controller. TC was kind enough to make the repairs before
> his trip to Colorado in mid-June. I got the unit back, reinstalled it last
> weekend, fired the engine up for a quick test last Tuesday night. Then
> yesterday (Saturday) I just ran the engine in my driveway for about an hour,
> playing with different settings. This is really when I noticed the engine
> running rough on A.
> 
> I had recorded some of the values (mode 3/Mode 2) from the May tuning
> sessions. I reset mode 3 to that same setting (203) but it made no
> difference, engine rough.
> 
> I swapped the crank sensor connections (A controller to B cps, and B
> controller to A cps), made no different. A was rough and B was smooth as a
> baby's behind.
> 
> I have an EM2, but as I understand things, the EM2 really can only see
> values of the A controller. Even when flipped to B.  And there is no way to
> back-copy from B to A. It is always A to B. Grrrrr
> 
> I also instaled a wideband O2 sensor for the purpose of tuning. That seemed
> to work OK, but I never really got a chance to use it.
> 
> So... I really need some ideas, suggestions, insights of what to try next.
> 


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