J.P. Instruments EDM 700, EDM 800, EDM 711 User Manual
Pilot’s Guide
Engine Data Management
EDM-700
EDM-800
EDM-711 Primary
Copyright 2000-2007 J.P. Instruments, Inc.
All Rights Reserved
J.P. INSTRUMENTS INC.
Information: P. O. Box 7033
Huntington Beach, CA 92646
Factory: 3185 B Airway
Costa Mesa, CA 92626
(714) 557-5434 (800) 345 4574
Fax (714) 557-9840
www.jpinstruments.com
www.jpitech.com
www.BuyJPI.com
Support@jpitech.com
Printed in the United States of America Rev W 3/2009
Last printed 10/17/2012 9:05:00 PM
Table of Contents
Section 1 - Introduction 1
Product Features 1
Engine Data Management 2
Benefits of Proper Mixture Control 2
JPI Probes 2
Temperature and Mixture 2
Section 2 - Displays and Controls 4
Displays 4
Modes 7
Buttons 8
Parameter Scan— EDM-700 without Fuel Flow Options 9
Automatic Parameter Scan—EDM-711 10
Section 3 - Operating Procedures 11
Diagnostic Testing on Startup and During Flight 11
Modes 11
Automatic Mode 11
Manual Mode 12
LeanFind Mode—Leaning Rich of Peak 12
LeanFind Procedure—General Explanation 13
Operation for each Phase of Flight 18
Shock Cooling 19
Common Misapplications 20
Section 4 - Diagnosing Engine Problems 21
Alarms 24
Pre-Ignition and Detonation 25
Section 5 - Fuel Flow Option Operation 26
Fuel Flow Display Select Switch 26
Fuel Management 28
Parameter Scan—Systems with Fuel Flow Option 28
Section 6 - Long Term Data Memory 30
Downloading from Long Term Memory 31
Downloading Data from the EDM to a Flash Drive 31
Downloading from USB Flash Drive to a PC 33
Section 7 - Personalizing 33
Pilot Programming 33
Section 8 - Programming the EDM-800 Horsepower Constant 35
Section 9 - Programming Manifold Pressure (MAP) 35
Section 10 - Programming use of Factory Original TIT Probe 36
Section 11 - Programming the Fuel Flow Option 38
Fuel Flow Option Programming Procedure 40
Section 12 - Programming Long Term Data Memory 40
Section 13 - EDM-711 Primary Alarm Display 41
Section 14 - Alarm Limits 42
MAP, Fuel Flow Alarm Limits, Units, Fuel Capacity 44
Navigation Data Formats 46
tap STEPand
GPS-C Fuel Flow Format for GPS Bi-directional Comm 46
Diagnostic Messages, Fuel Flow 47
Navigation Data Ports for GPS Comm 47
Section 15 - Option Connector Pin Assignments 48
Section 16 - Reference Reading 49
Section 17 - Technical Support 49
Limited Warranty 50
Index 51
How to Change Modes (page 7)
EDM-700 enters Automatic mode two minutes after power up
AUTO INDEX
parameters
automatically
indexed
Toggle between
LEAN R and
LEAN L of peak
tap LF,then tap STEP
L
F
S
T
E
P
E
T
S
h
t
F
o
L
b
d
d
l
n
e
o
a
n
h
a
t
l
u
m
i
s
tap STEPbutton
LEAN FIND
starts LeanFind
procedure
P
y
l
s
u
o
LFsimultaneously
MANUALINDEX
parameters
indexedwhen
step intapped
LF
In Leanof peak, afterfirst
LeanFind, LF will returnto the
inverted bar graph. TapLF againto
start LeanFind procedure
b
e
g
l
e
in
a
n
i
n
g
dot flashes
release buttons
continue
leaning
Toggle to include/
exclude
parameterin
indexing
see
LEANEST
hold LF
release
LF
Displays
peak EGT
value
Section 1 - Introduction
Product Features
indicates standard feature
Hands-free, automatic scanning (711: primary only)
All programming done from the Front Panel
LeanFind finds the first and last cylinder to peak
with true peak detect—eliminates a false peaks
Displays both leaned temperature below peak and peak
Battery voltage with alarm
24 Programmable alarm limits
Normalize view
DIF low to high EGT with alarm
EGTs to stable 1°F resolution
Shock cooling monitored on every cylinder
User selectable index rate
Fast response probes
Non-volatile long term memory
Records and stores data up to 30 hours
Post-flight data retrieval
Data retrieval software
FAA Approved as primary temperature instruments for
CHT, OIL, TIT
Alarm and warning light panel
Oil temperature opt
Turbine inlet temperature opt opt opt
Outside air temperature opt opt
Compressor discharge temperature opt opt opt
Carburetor temperature opt opt opt
Fuel Flow FF opt FF opt
Solid-state rotor fuel flow transducer FF opt FF opt
Fuel quantity in gallons, kilograms, liters, or pounds FF opt FF opt
Low fuel quantity alarm FF opt FF opt
Low fuel time alarm FF opt FF opt
GPS interface FF opt FF opt
Instantaneous fuel flow rate FF opt FF opt
Total amount of fuel consumed FF opt FF opt
Total fuel remaining FF opt FF opt
Time to empty at the current fuel flow rate FF opt FF opt
Displays % horsepower and RPM
Automatically calculates percent horsepower
700 711 800
RPM opt RPM opt
opt
For Your Safe Flight Page 1
Engine Data Management
The EDM Engine Data Management system is the most advanced and
accurate piston engine-monitoring instrument on the market. Using the
latest microprocessor technology, the EDM will monitor up to twentyfour critical parameters in your engine, four times a second, with a
linearized thermocouple accuracy of better than 0.1 percent or 2 F°.
As your built-in flight engineer, the EDM is constantly “red line”
checking: all critical parameters are automatically checked four times a
second, regardless of the current display status. Leaning is accomplished
quickly and automatically using the LeanFind procedure. With the
EDM it is now possible to have substantially more diagnostic
information available to you in a timely and usable manner.
The real-time serial data port—a standard feature—permits you to
record scanned parameters in real-time using a user-supplied laptop PC.
Benefits of Proper Mixture Control
Improved engine efficiency Reduced maintenance costs
Greater fuel economy Reduced operating costs
Smoother engine operation Proper engine temperatures
Longer spark plug life Reduced engine vibration
JPI Probes
Temperature information
processed by the EDM is captured
by fast response, grounded
JPI
temperature probes, that accurately
cylinder
head
CHT probe
exhaust
manifold
measure the small temperature
changes—as small as 1°F—that
EGT probe
occur during mixture adjustment.
Temperature and Mixture
In a piston engine only a small portion of the energy from combustion
produces movement of the piston during the power stroke. The majority
of energy passes into the exhaust pipe as hot gasses. By monitoring the
temperature of these exhaust gasses you will have an indication of the
quality of the combustion process. Low compression, non-uniform fuel
distribution, faulty ignition, and clogged injectors diminish the
efficiency of the combustion process that generates power.
Page 2 Engine Data Management
From the cockpit you can adjust the fuel/air ratio by a process called
leaning. Retarding the mixture control changes the fuel/air ratio and
hence the resulting Exhaust Gas Temperature (EGT).
The following figure depicts the mixture and temperature relationship.
-100
EGT °F below peakPercent of best power
-50
100
95
90
85
80
Best
power
range
0
T
First
G
E
T
H
C
e
c
r
e
P
peak. Use for
Rich of Peak
w
o
p
t
n
S
p
e
c
cylinder to
leaning
r
e
i
f
i
c
f
u
e
l
c
o
economy
range
n
s
u
m
p
Best
t
i
o
n
GAMI
spread
Peak Power
Last
cylinder to
peak. Use for
Lean of Peak
leaning with GAMI
injectors
20
0
-20
-40
-60
-80
CHT °F change from
best power
Full Rich
(Take-off)
Rich
Lean
Too
lean
As the mixture is leaned, EGT rises to a peak temperature, and then
drops as the mixture is further leaned. Peak power occurs at a mixture
using more fuel than at peak EGT. Best economy occurs at peak EGT.
Accurate leaning yields optimal engine temperatures. By being able to
precisely adjust the mixture, your engine can produce either the best fuel
economy or maximum power, whichever you choose.
For Your Safe Flight Page 3
A single EGT gauge merely gives you an average of each cylinder’s
temperature: some cylinders can be too rich, while others too lean.
Variations produced by differences in fuel distribution, ignition, and
compression will cause each cylinder to follow its own mixture and
temperature relationship such that one cylinder will reach peak before
another.
Section 2 - Displays and Controls
The EDM monitors engine temperatures and voltages, assists in
adjusting the fuel/air mixture, and helps diagnose engine malfunctions.
There are three components of the user interface:
Analog display including cylinder number and index dot
Digital display for numeric readouts and messages
Two front panel operating buttons.
Displays
°F or°C
F
_
EGT
%
Limit
_
Dotindicates which
cylinder temperatures
areshownin the
digitaldisplay
Exhaust Gas
Temperature
(EGT) is thetop of
thecolumn
Systems with
both TIT and
OIL,OILis
shownas
missing segment
Dashline or
NRMindicates
Normalizeor
Percentview
Maximum
lineis the
EGT, TIT
and OIL
Cylinder Head
(CHT)is shown
redline
CHT
absolute
scale
Temperature
as amissing
segment
Cylinder
numbers 1
through6. T is
TIT otherwise
oiltemp
NRM
1 2 3 4 5 6 T
TSO
CHT
450
350
250
I340 376
STEP LF
EDM 800
Percent
HP
orRPM
(EDM-
800only)
7 3
J
P
I
HP
Analog Display
The upper half of the face of the EDM is the analog display with %HP.
The following is a description of the analog display, from top to bottom.
Numbers in circles refer to features in the above diagram.
Page 4 Engine Data Management
Normalize and Percentage View Indicators
Percentage view: when there is a dash — near the P at the top of
the display (EDM-700) or NRM is not lighted (EDM-800), the
columns indicate percent of EGT red line. Each column is
composed of a stack of segments. A maximum height column
depicts 100 % of red line and a one segment-high column
depicts 50 % of red line. For example, if the red line is 1650°F, a
maximum height column represents 1650°F and a one segmenthigh column represents half that value, or 825°F. The
Percentage view permits comparison of EGTs across all
cylinders. Hotter cylinders display higher columns than cooler
cylinders.
Normalize view: when there is a dash _ near the N at the top of
the display (EDM-700) or the letters NRM are lighted on the left
side (EDM-800), the EGT columns are displayed normalized.
When you change to the Normalize view, all column peaks are
set to the same half-height level for trend analysis. Any changes
are shown as an increase or decrease in column height. A one-
segment change in column height represents a 10°F change.
The Normalize view permits rapid visualization of EGT trends,
rather than a percentage of red line. You should use normalize in
level cruise and run-up.
To toggle between Percentage and the Normalize views, hold the LF
button for five seconds until the display changes. The analog display
becomes half height and the display changes to the Normalize view.
Selecting the Normalize view does not affect the digital display nor alter
the parameter sequence. The CHT display—described later—is not
affected by the Normalize or Percentage view.
You may select the Normalize view in either the Manual or Automatic
mode. Normalize view is most helpful for engine trend monitoring of
each cylinder’s operation. For example using the Normalize view during
engine run-up, a fouled spark plug will appear as a higher column.
A common misapplication is to be in the Normalize view and then
change your power setting, causing all columns to go off scale, high or
low. Set to the Percentage view before adding or reducing power.
Always set Percentage View when beginning your descent.
Temperature Units (°F or °C)
°F temperatures in the digital display are in Fahrenheit degrees.
°C temperatures in the digital display are in Celsius degrees.
For Your Safe Flight Page 5
To change the display of engine temperatures see “Changing the
Alarm Limits” on page 42.
Cylinder Numbers and Dot Index
A row of numbers 1 through 6 and the letter T are the column labels for
the analog display. The 1 through 6 are the cylinder numbers. If the TIT
option is installed, the T denotes the last column is displaying Turbine
Input Temperature (TIT) as a column. If the T is absent and the Oil
temperature option is installed, the last column displays Oil temperature.
If both TIT and Oil temperature options are installed, the last column
displays TIT and the missing segment displays Oil temperature. The
highest Oil temperature segment will flash only when the digital display
shows OIL. The highest TIT segment will flash on when the digital
display shows TIT. A round dot under the numbers 1 through 6 indicates
that particular column is shown numerically in the EGT and CHT digital
display.
Bar Graph EGT and CHT
Each column in the bar graph is composed of a stack of segments. The
total height of each column represents the EGT and the missing segment
in the column represents the CHT.
In the Percentage view, the EGT, TIT, and Oil temperature
resolutions depend on the programmed red line limits.
CHT is displayed by a missing segment and
should be interpreted as follows: a missing
segment corresponds to the CHT in 25 F°
increments, starting at 250°F at the bottom. In
CHT
450
350
250
the example shown here, the CHT is 300°F. If the EGT bar
is lower than the missing CHT segment, then the CHT will
be indicated by a single isolated lighted segment.
The CHT display is the not affected by mode or view.
Percent HP (EDM-800 only)
Displays percent of rated HP or RPM depending on pilot programming.
Digital Display
Beneath the bar graph is the 9-segment alphanumeric display.
EGT and CHT
When the dot index is beneath a cylinder number, 1 through 6, the digital
display shows the EGT on the left (four digits) and the CHT on the right
Page 6 Engine Data Management
(three digits). Other parameters are displayed in the digital display as
described in the subsection “Parameter Scan— EDM-700 without Fuel
Flow Option” on page 9. The EDM-711 will briefly display EGT – CHT
before displaying the numerical values.
HP
4 digit
displayof
EGT
NRM
1 2 3 4 5 6 T
TSO
CHT
450
350
250
I340 376
STEP LF
EDM 800
73
J
P
I
F
_
EGT
%
Limit
_
3 digit
displayof
CHT
Display Dimming
The entire display panel features automatic dimming. Allow ten seconds
for the display to adjust to ambient lighting conditions.
Modes
There are three standard operating modes of the EDM: Automatic,
Manual, and two LeanFind submodes. These modes will be described in
more detail beginning on page 11. Most of the time you will operate the
EDM in the Automatic mode. When you first turn on the power the
EDM starts in the Manual mode, but will enter the Automatic mode after
two minutes. The three modes affect primarily the digital display.
Automatic Mode
Just tap the LF button, then tap the STEP button. No user
intervention is required to use this mode. Each cylinder and each
parameter value is automatically sequenced and shown in the digital
display for a few seconds. The EDM-711 will automatically scan only
the primary temperatures: highest CHT, TIT, OIL.
Manual Mode
Just tap the STEP button. Automatic stops. Each indexed parameter is
frozen in the digital display until you manually index to the next
parameter by tapping the STEP button. The EDM-711 will manually
scan all parameters.
For Your Safe Flight Page 7
LeanFind Mode
Simply pre-lean, tap the LF button and begin leaning. The EDM will
assist you in finding the first cylinder to peak.
Buttons
I340 376
STEP EDM-700 LF
J
P
STEP button LF button
Buttons, Front Panel
Two operating buttons control all functions of the EDM.
The term tap will be used to denote pressing a button momentarily. The
term hold will be used to denote pressing and holding a button for five
seconds or longer.
STEP Button
Located on the lower left side near the instrument face.
In the Automatic mode, tapping the STEP button will stop
and change to the Manual mode. Then each tap of the STEP
button will display the next parameter in the sequence.
I
In the LeanFind mode tapping the STEP button will
terminate the LeanFind mode and change to the Automatic
mode.
Secondary functions of the STEP button include:
In the Manual mode holding the STEP button will display the previous
parameters in the sequence (rapidly backwards).
In the programming procedures, tapping the STEP button will advance to
the next item in the list.
When an alarm is displayed, tapping the STEP button will temporarily
delete that alarm from appearing for the next ten minutes.
When an alarm is displayed, holding the STEP button until the word OFF
appears will delete that alarm from appearing for the remainder of the
flight.
LF Button
Located on the lower right side near the instrument face.
Page 8 Engine Data Management
In Automatic or Manual modes, tapping the LF button will
change to the LeanFind mode.
In Automatic or Manual modes holding the LF button for
three seconds will toggle between Percentage and Normalize
views.
hold LF button
for 3 seconds
In the LF mode holding the LF button after peak EGT is
found will display peak EGT.
Secondary functions of the LF button include:
In the pilot programming procedure, holding or tapping the LF button is
used to increment or decrement parameter values and toggle between Yes
and No answers to questions.
STEP and LF Buttons
Holding both the STEP and LF buttons simultaneously for
five seconds changes to the pilot programming procedure.
Holding both the STEP and LF buttons simultaneously for
five seconds after entering LeanFind mode but before
beginning to lean will toggle between leaning “rich of peak”
and “lean of peak.”
Tapping both the STEP and LF buttons simultaneously in
Manual mode toggles to include or exclude the displayed
parameter from the Automatic mode. It has no affect on the
displayed parameters in the Manual mode.
N: Normalize viewP: Percentage view
In the LF mode tapping both the STEP and LF buttons
simultaneously will mark a data record in long term
memory and display will flash SNAP.
Parameter Scan— EDM-700 without Fuel Flow Options
The EDM steps through the engine parameters in a specific sequence.
Listed below is the sequence, parameter description and example of the
digital display.
For Your Safe Flight Page 9
Parameter Example Comments
Voltage, System Bus
I4.2 BAT
Battery voltage
Outside Air Temperature
Induction Air
Temperature
Compressor Discharge
Temperature
Carburetor Temperature
Difference between
hottest and coolest EGT
EGT, CHT
TIT, Turbine Inlet
Temperature
Oil Temperature
Shock Cooling
8I OAT
I25 IAT
300 CDT
-22 CRB
80 DIF
I340 376
TIT
TI2
I78 OIL
-30 CLD
°F or °C
Out of the intercooler
Into the intercooler
Not available when CDT is
installed
Dot indicates most widely
deviating cylinder
EGT, left, CHT, right. Dot
indicates cylinder
Turbine #1, left shows as
column.
Turbine #2, right
Missing bar in TIT column or is
column
Dot indicates fastest cooling
cylinder
The display will pause at each parameter for four seconds in the
Automatic mode. (The four second pause time can be changed.) In the
Manual mode, tap the STEP button to advance to next parameter. Only
the parameters for the options that are installed will be displayed;
uninstalled parameters will not appear.
Automatic Parameter Scan—EDM-711
The EDM-711 in automatic scan mode will display only the following
three primary temperatures: highest CHT, OIL and if the option is
installed, TIT.
Page 10 Engine Data Management
Section 3 - Operating Procedures
Diagnostic Testing on Startup and During Flight
When your EDM is first turned on, all digits light up for a few seconds,
permitting you to check for non-functional segments. Then each column
is self-tested in sequence while the EDM tests internal components,
calibration and integrity of the probes. If a problem is found, it will be
displayed as OPEN PRB or CAL ERR, followed by the name of the probe or
channel.
Display Channel Display Channel Display Channel
EGT I
EGT 2
EGT 3
EGT 4
EGT 5
EGT 6
EGT #1
EGT #2
EGT #3
EGT #4
EGT #5
EGT #6
CHT 2
CHT 3
CHT 4
CHT 5
CHT 6
CHT I
CHT #1
CHT #2
CHT #3
CHT #4
CHT #5
CHT #6
OIL
TIT I
TIT2
CDT CRB
IND
OAT
Oil
TIT #1
TIT #2
CDT carb
IAT
OAT
During flight, probes are constantly checked for inconsistent or
intermittent signals. A faulty channel or probe encountered during startup or during flight will be deleted from the sequence, producing a
missing column or blank digital data.
Modes
The EDM has three different operating modes: Automatic, Manual and
LeanFind. When you first turn on the power the EDM starts in the
Manual mode, but will enter the Automatic mode after a few minutes.
The Automatic mode provides you with engine monitoring information
for the majority of flight conditions. To adjust the mixture, use the
LeanFind mode. And to display specific parameters, use the Manual
mode. In both the Automatic and Manual modes the analog display
shows a bar graph of EGT and CHT for each cylinder and the TIT and
Oil temperature.
Automatic Mode
Just tap the LF button, then tap the STEP button. No user
intervention is required to use this mode. In the Automatic mode the
EDM displays the parameter sequence at a user-selected rate (see
“Personalizing” on page 33).
Individual parameters can be excluded from the Automatic mode
(exclusion does not apply to the EDM-711): tap STEP to enter the
Manual mode. Tap STEP to index to the parameter you want to exclude.
For Your Safe Flight Page 11
Then tap both the STEP and LF buttons simultaneously. Excluded
parameters display a decimal point before the parameter name. For
example:
Included: I84 OIL Excluded: I84 .OIL
Tapping the STEP and LF buttons simultaneously will toggle back and
forth between include and exclude.
Every time you turn on the EDM, all parameters are reset to be
included.
All installed parameters are always displayed in the Manual mode.
Exclusion only applies to the Automatic mode.
All parameters are checked for alarm conditions every second
regardless of their included or excluded status.
Manual Mode
Just tap the STEP button. Use the Manual mode when you want to
monitor one specific parameter such as shock cooling during descent, or
a particular cylinder temperature during climbs. To change to the
Manual mode, tap the STEP button once. Subsequent taps will index the
digital display through the parameter sequence (see “Parameter Scan—
EDM-700 without Fuel Flow Option” on page 9). To exit the Manual
mode and return to the Automatic mode, either tap the LF button and
then tap the STEP button—see “How to Change Modes” in the front of
this manual. You may disable the Automatic mode by setting “0” for
scan rate (disabling Automatic mode does not apply to EDM-711).
LeanFind Mode—Leaning Rich of Peak
JPI’s EDM-700 and EDM-800 provide two methods of leaning: lean
rich of peak (LEAN R) or lean of peak (LEAN L). The standard method is
to lean about 20° rich of peak. With the advent of GAMI injectors it is
now possible to set the mixture lean of peak—saving fuel and running
the engine cooler. Teledyne Continental recommends lean of peak for
the Malibu. This manual primarily describes the rich of peak method,
and provides the procedure for the lean of peak method. The default
method is set to rich of peak.
Simply pre-lean, tap the LF button and begin leaning. Upon reaching
cruise configuration, you will use the LeanFind mode to identify the first
cylinder to reach peak EGT.
Page 12 Engine Data Management
LeanFind Procedure—Step-by-Step
Procedure Example Comments
Establish cruise at approx.
1
65 to 75% power.
Pre-lean the mixture to 50°F
2
estimated rich of peak EGT
on any cylinder: _____°
Wait one minute Let engine stabilize.
3
Tap the LF button
4
Lean the mixture—approx.
5
10°/second without
pausing—while observing the
display. When there is a 15°F
rise in EGT, LeanFind mode
becomes active.
Stop leaning when
6
a column begins flashing.
You will see LEANEST for two
seconds, followed by:
I490 370
LEAN R
I520 LF
Without FF
I520 I3.8
With FF
I545 SET
or with
Fuel Flow
I545 I 2.4
If you hold LF, peak EGT will
7
be displayed while the LF
button is held down.
Slowly enrich the mixture. the
8
temperature will increase,
returning to peak.
Stop enriching at the desired
EGT.
Best economy
Best power
If you have chosen the Lean
9
of Peak method, at step 5
continue leaning until the last
cylinder has peaked.
I560 PK
I560 SET
I560 SET
I460 SET
-I5 SET
OR
-I5 I2.3
*For your first flight with the
EDM, use the method shown
below.
Start LeanFind. (Optionally to
change to “lean of peak”
method, hold both STEP and
LF simultaneously.)
Flashing cylinder DOT
indicates hottest cylinder and
that LeanFind mode is active.
Flashing cylinder dot &
column indicates leanest
cylinder. (SET means Set the
mixture.) Due to thermal
inertia this will usually be
about -15°F lean of peak.
Captured peak EGT value is
displayed.
Peak EGT for best
economy
100° rich of peak for best
power
Best
power
richer
Only for GAMI injected
engines. When each cylinder
reaches peak, the cylinder
number will begin flashing.
Temperature when
column flashes
leaner
best economy
*Determining the pre-lean value: while in cruise at under 65 percent
power, choose any cylinder and lean that cylinder to peak EGT in the
Manual mode or to engine roughness, whichever occurs first. Note the
peak, subtract 50° and write the resulting number in the space provided
in step 2.
LeanFind Procedure—General Explanation
For Your Safe Flight Page 13
Lycoming and Continental engines have established specific
restrictions on leaning that must be followed, such as
percentage of power, climb leaning, and TIT limits. Lycoming
recommends operation at peak EGT for power settings of
75% or lower, while Continental recommends operation at
peak EGT for power settings of 65% or lower. This guide is
not meant to supersede any specific recommendations of the
engine manufacturer or airframe manufacturer.
It is your responsibility to know your aircraft’s limitations.
Pre-lean the mixture to about 50° below peak. After pre-leaning, wait for
one minute for the temperatures to stabilize. Next, begin the leaning
process by tapping the LF button. This tells the EDM to begin looking
for a 15° rise in EGT for any cylinder. Begin leaning the mixture without
pausing. When a 15° rise occurs, eliminating false peaks, the LeanFind
mode becomes activated shown when the cylinder dot above the column
of the hottest cylinder begins flashing. The LeanFind mode is not
active until a cylinder dot is blinking.
With the Fuel Flow Option, instead of seeing the word LF in the
display, you will see numerical fuel flow rate during the leaning
process on the right side of the digital display, for example I2.4.
This allows you to observe the EGT rise and at the same time
watch the fuel flow rate decrease.
To show the progress of the leaning process, the EDM selects the hottest
cylinder for reference in the digital display. In the example below, the
I360 is the current temperature of the hottest cylinder.
When LF is activated:
number of
hottest cylinder
flashes when
EGT rises 15°
dot
indicates
hottest
cylinder
temperature
and "LF"
displayed
TSO
CHT
500
400
300
Page 14 Engine Data Management
N P
1 2 3 4 5 6 T
° F
_
I360 LF
STEP EDM-700 LF
J
P
I
_
EGT
%
Limit
_
Continue leaning slowly without pausing. With a vernier mixture
Leaning Rich of Peak
control, turn the knob about a quarter turn every second. With a nonvernier or quadrant mixture control, lean slowly and smoothly about
1/16 inch every five seconds. Eventually, one cylinder will reach peak
before any of the other cylinders. The EDM will determine this
automatically. Notice that this cylinder does not necessarily have the
hottest EGT.
The EDM will indicate success in finding a peak by displaying the
words LEANEST for two seconds, followed by flashing the column and
displaying the value of the EGT of the cylinder that peaked first. The
word SET will also be displayed. (With the Fuel Flow Option the current
fuel flow rate will be displayed on the right side of the digital display
instead of the word SET.) The flashing cylinder will be locked—or set—
into the digital display during the remainder of the LeanFind procedure
to allow you to set the final mixture. The peak EGT value is remembered
by the EDM and will be displayed as long as you hold the LF button.
You may now enrichen the mixture to operate at peak or continue
enriching to 100° rich of peak, or a value of your choice, consistent with
the procedures defined in your aircraft engine manual.
If you lean too much, the EGT will drop and the engine will be operating
lean of peak.
LEANEST
displayedfor
twoseconds
whenpeak is
found
LEANEST
N P
1 2 3 4 5 6 T
TSO
CHT
450
350
250
I340 SET
STEP EDM-700 LF
_
° F
J
P
I
Cylinder
number of the
LEANEST
cylinder flashes
Dotindicates
_
_
LEANEST
EGT
cylinder
%
Limit
Columnof the
LEANEST
_
cylinder flashes
EGT of the
LEANEST cylinder
displayed withthe
thewordSET
Lean of Peak Leaning with GAMI injectors
For Your Safe Flight Page 15
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