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All,
I have been working on getting my EC-2 tuned
to get smooth engine operation over the entire range.
I used Mode 1 to do the initial tuning, and got it
to run reasonably well with some roughness at various points.
I then used the auto tune feature on the ground,
running the engine up to higher and higher RPM and letting it tune in the
settings.
At that point I thought I was pretty much there,
with one exception.
When idling (600 rpm prop, 1710 engine) and
increasing the throttle slowly (with a vernier throttle, rotating the knob), the
engine would accelerate pretty smoothly all the way up, however, If I Pushed the
throttle in quickly, the engine would hesitate, buck, jump up and down in MP
until suddenly it would scream to life at 3000 engine rpm and then be
smooth.
I finally figured out what the issue was. When auto
tuning (or manual tuning) on the ground, the MAP table values at low RPM (Low
manifold pressure) are selected from the low rpm table (values 0-63). As I
slowly advanced the throttle, the EM-2 brought each table value into good order,
but at ~2400 rpm it switches to the high table value and keeps going on
adjusting the table values.
When advancing the throttle rapidly, the Manifold
pressure rises quickly, the RPM is still low, so the EC-2 selects values that
were never adjusted in the previous process, the engine ran rich (very), bucked
and snorted until the RPM gets to the high table, and then smoothed
out.
I finally figured this out by using the Track Mode
on the EM-2 and watching the bin # as the throttle was advanced using the
vernier. It would increase 2,3,4,5,6, 72, 73...etc.
When the throttle was advanced quickly, the bin
numbers went 2,3,4,5,6,14,12,15,13, 72, etc. By then turning the engine
off, and manually adjusting the values in bins 8-14 to the same value as 73, the
engine is much smoother during acceleration.
Bill Schertz
KIS Cruiser
#4045
N343BS
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