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Yeah Dave, I plan to order one of Ed's gauges soon!
I didnt forget. Just been tied up with other stuff and not much time for the
plane lately.
Mike Wills
RV-4 N144MW
----- Original Message -----
Sent: Tuesday, July 22, 2008 7:12
AM
Subject: [FlyRotary] Re: The SAGA
continues; More checking basics and development progress
Mike,
I second what Ed said.
I knonw your panel space is a little tight, but remember that my biggest
suggestion was to get Ed's EFI monitor. It has helped me far more than
any other single thing I have done. Not just for the mixture map
but lately I have been working on injector balance and it is very helpful
there as well because you can also see exactly the injector balance both
front/rear and side to side.
The fuel flow/totalizer is a really nice feature as well, but it was
worth it to me just to get the EC2 monitoring functions.
Dave Leonard
On Mon, Jul 21, 2008 at 10:50 PM, Ed Anderson < eanderson@carolina.rr.com>
wrote:
Mike,
Don't know whether
this may apply or not. But, for a number of years, I always had a
stumble when the injector staged (went from 2 to 4). It would not stop
the engine and you never noticed it in flight, but anytime you push the
throttle past the staging point on the ground, it would basically sag
and the Air/Fuel ratio indicator would run off the lean end of the
scale. So I suspected it was a moment of too much air and too little
fuel . But, in any case even though I did try enriching that
region it never seemed to make much difference.
Once I completed my
EFISM gadget so I could visually see the fuel map and where my engine was
operating on it, it was very easy to see that the fuel map dropped off from
the higher values needed for idle to lower values. So now that I could
see exactly which bars were causing the Air/Fuel ratio indictor go lean, I
could start increasing those specific fuel Map bars. It took quite a
bit of increase across a region of about 3-4 bars (manifold pressure bins)
but I finally got it to the point there was absolutely no hint of a stumble
or sag as the engine staged.
So at least in my
case, it was a case of the engine just being too lean in that region.
I hypothesize that when for an instance when the EC2 cuts from the two
primary injectors pumping all the fuel into the primary runners (and at this
point with NO fuel in the secondary runners), that the mixture is
initially just a bit too lean and it takes an instant of time for things to
get things squared away air/fuel ratio wise. But, just a guess on my
part.
In any case, if you
have Tracy's EM2 you can monitor those bars and see what they tell
you.
Ed
From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Tuesday, July 22, 2008 12:02
AM
To: Rotary motors in
aircraft
Subject:
[FlyRotary] Re: The SAGA continues; More checking basics and development
progress
Thanks for the input. I
still havent had a chance to get back to any serious engine tweaking yet. I
too assumed a big step somewhere in the bottom of the MAP
table.
You updated my EC2 in
January so I assume it is current or at least pretty close. I redid the
programming after i got it back from you, following the instructions in the
updated manual.
At this point I'm hesitant
to restore defaults because i feel like it is pretty close. But if I
cant get it figured out that is what I'll do.
----- Original Message -----
Sent:
Monday, July 21, 2008 8:14 AM
Subject:
[FlyRotary] Re: The SAGA continues; More checking basics and development
progress
A big
step in the MAP table is almost always the problem here.
Specifically, it sounds like the low end of the table (low MP) is too
lean. This would be the point where the MP is at its lowest
point which is usually around 2000 - 2300 rpm (with prop on).
Don't know what version software you are
running Mike but during the past couple of years the software has had MANY
changes aimed at making the MAP table programming less critical and
easier. If you have recent software, the best thing to do is go back
to default MAP then program Mode 3 and 2 (in that order) per the
instructions before doing ant MAP table programming. After doing
this. very little table programming is usually needed. Note that
Mode 2 is no longer the program address range, it is now the injection
dynamic range. It acts like the low speed / idle jet
adjustment in 'carburetor language'. Mode 3 is the 'high speed
jet' adjustment.
You
might also try loading the alternate default MAP by resetting default MAP
with the cold start switch UP instead of down. Remember to reset the
CS down after doing this.
On
Fri, Jun 20, 2008 at 11:33 PM, Mike Wills <rv-4mike@cox.net>
wrote:
I too still have intermittent
surging issues that havent been fully conquered. Doesnt happen all the
time. Always in the 2000 - 3000 RPM range. Usually happens when I'm
taxiing and back off the throttle. In my case the A/F reading is useless.
The engine surges rhythmically at about a 1Hz rate with RPMs varying
several hundred, MAP varying from high to low (hard to pin down exact
numbers - its moving around too much), and the A/F bouncing back and forth
from the rich stop to the lean stop. Fiddling with mixture always stops
it, but its a little disconcerting (and embarassing) when it happens
(usually as I'm taxiing away from the crowd at the local EAA chapter while
everyone is watching). For a while I thought adding some capacity to the
MAP sensing line (Dave Leonard's suggestion) had cured it, but not
entirely. I'll need to get this figured out before it flies. Could be a
real problem if it happens on short final.
I occasionally have a pretty
good backfire at the secondary staging point. The operational solution
seems to be to not linger in the area - just advance the throttle or
retard it right on through and it seems to be OK. Advancing the throttle
too slowly almost guarantees a big pop! I'm told it's particularly
impressive after dark!
I havent worked on the tuning
in months while I've been tweaking other little issues in prep for my DAR
inspection. Just about ready to get back to it. I'm sure i'll get it more
or less figured out eventually.
----- Original Message -----
Sent:
Friday, June 20, 2008 7:06 PM
Subject:
[FlyRotary] Re: The SAGA continues; More checking basics and development
progress
Chris,
As you've probably read from the
archives surging is usually caused by an overly lean air-fuel
ratio. What is your A/F reading during the surging?
Mark S.
On
Fri, Jun 20, 2008 at 8:41 PM, Christopher Barber <CBarber@texasattorney.net> wrote:
Well, to continue the saga,
I have not run the new 13b much since I got it running a few weeks ago
due to the EM2 not showing oil pressure as it should. It was
giving me erratic readings like -1, -3 etc. I hand propped the
engine before I ran it and oil pumped through the system fine....much
onto the hangar floor...alas, the sacrifices for certainty ;-).
Also, during my short runs everything heated up in the oil system evenly
and the oil temp stayed pretty much in line with coolant temp.
BUT, since I was not sure if this was a gage/sender issue or an actual
oil system problem I was very cautious about my few short engine
runs.
Well, today while dreading
the idea of dropping my pan, I happened across an extra oil pressure
sender (still in the package) I happened to have. I had seen it
laying around for a while, but didn't give it much thought until I was
thinking about dropping the pan. Low and behold, The problem was the
sender. I am getting good pressure reading now, along with coolant
and oil temp. Yeah. I am surprised at the temps as they seem to be
staying in check considering the 95 + degree Houston
weather.
I am able to start the
engine, shut it down and restart it (something I was not able to do with
the old engine). It is somewhat difficult, but seems to be getting
easier as I continue to tweak things (ie timing). I am trying to
do the various tuning via Tracy's manual. To be honest a lot
of the information in the manual is seemingly abstract until I actually
get to the step and/or problem. So, tonight, I got it to run, and
it seems to run better, but......
I am having a surging
problem. It seems intermittent, but it just may be I have not been
setting the throttle quite the same way as I get use to it all.
Also, I have had the coil C/B pop on me several times now....it seems as
if this is when the engine is near or at idle. I have not had a
chance to look into this as of yet. Also, I have gotten a number
of horrendously loud/powerful backfires. Not sure what changes as
the engine may have run fine. It backfires when attempting to
start. I wait a few minutes and it may then start. Gee,
isn't inconsistent crap fun <g>
I just did a search of the
archives on the surging issue, but have just started reading the 105
post on the topic. Seems our own Mr. Slade had the same problem
back in the day <g>.
Well, it is the middle of my
work week and I gotta turn in soon, but I wanted to share that it seems
as if actual progress is being made (hmmmm, wonder what will screw this
positive statement up<g>) as the Saga
continues.
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-- David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.nethttp://RotaryRoster.net
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