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

[phone] [phone] Fax [phone] www.jpinstruments.com www.jpitech.com www.BuyJPI.com [e-mail]

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
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

	tap STEP button		tap STEP and
			LFsimultaneously
AUTO INDEX		MANUAL INDEX		Toggle to include/
parameters		parameters		exclude
automatically		indexed when		parameter in
indexed	tap LF, then tap STEP	step in tapped	release buttons	indexing

L F S TEP

LF

LEAN FIND starts LeanFind procedure

In Lean of peak, after first LeanFind, LF will return to the inverted bar graph. Tap LF again to start LeanFind procedure

						P
					E
				T
			S						ly
		th			F
	o								s
b				L				u
ld			d				o
		n				e
o	a				n
h				a
			lt
		u
	im
s

Toggle between

LEAN R and

LEAN L of peak

b
l	e
	g
e		in
a
n
	i
	n
	g

	continue		hold LF	Displays
	leaning	see
	dot flashes			peak EGT
		LEANEST	release
				value
			LF

Section 1 - Introduction

Product Features

 indicates standard feature	700	711	800
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		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	RPM opt	RPM opt	
Automatically calculates percent horsepower			

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 measure the small temperature changes—as small as 1°F—that occur during mixture adjustment.

Temperature and Mixture

	CHT probe
cylinder	exhaust
head	manifold
	EGT probe

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.

Percent of best power EGT °F below peak

0

-50

-100

100

95

90

85

80

Best									Best
power								economy		Last cylinder to
range									range	peak. Use for
										Lean of Peak
										leaning with GAMI
										injectors

T		First cylinder to
G
E		peak. Use for
		Rich of Peak
				leaning
	T
H
C

								r
							e
						w
					o
				t	p
			n
		e
	rc
e
P

GAMI spread

20

0

-20

-40

-60

-80

°F change from	best power
CHT

Peak Power

S
p
e
c
i
f
i
c
f
	u
	e
	l
	c
	o
	n
	s
	u
	m
	p
	t
	i
	o
	n

Full Rich	Rich	Lean	Too
(Take-off)			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



Dash line or 

Cylinder

 Percent



Dot indicates which

NRM indicates

numbers 1

HP

 °F or °C

cylinder temperatures

Normalize or

through 6. T is

or RPM

Percent view

TIT otherwise

(EDM-

are shown in the

digital display

oil temp

800 only)

Maximum

line is the



EGT, TIT

NRM

7 3 HP

F

Exhaust Gas

and OIL

1

2 3 4 5

6 T

Temperature

redline

TSO

_

(EGT) is the top of

EGT

the column

CHT

CHT

%

absolute

450

Limit

 Systems with

scale

350

_

both TIT and

250

Cylinder Head

OIL, OIL is

I340 376

shown as

Temperature

missing segment

(CHT) is shown

STEP

LF

as a missing

EDM JPI 800

segment

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 onesegment 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	CHT
should be interpreted as follows: a missing	450
segment corresponds to the CHT in 25 F°	350

250

increments, starting at 250°F at the bottom. In

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.

		NRM			73 HP			F
			2	3	4	5	6
	TSO	1						T	_
									EGT
	CHT								%
	450								Limit
	350								_
	4 digit 250
	display of	I340 376							3 digit
	EGT
		STEP						LF	display of
			EDM JPI 800

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
JPI	LF button
STEP 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.

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.

	P: Percentage view	hold LF button	N: Normalize view
		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.

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	8I OAT	°F or °C
Induction Air	I25 IAT	Out of the intercooler
Temperature
Compressor Discharge	300 CDT	Into the intercooler
Temperature
Carburetor Temperature	-22 CRB	Not available when CDT is
		installed
Difference between	80 DIF	Dot indicates most widely
hottest and coolest EGT		deviating cylinder
EGT, CHT	I340 376	EGT, left, CHT, right. Dot
		indicates cylinder
TIT, Turbine Inlet	TIT	Turbine #1, left shows as
Temperature	TI2	column.
		Turbine #2, right
Oil Temperature	I78 OIL	Missing bar in TIT column or is
		column
Shock Cooling	-30 CLD	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 #1		CHT I	CHT #1		OIL	Oil
EGT 2	EGT #2		CHT 2	CHT #2		TIT I	TIT #1
EGT 3	EGT #3		CHT 3	CHT #3		TIT2	TIT #2
EGT 4	EGT #4		CHT 4	CHT #4		CDT CRB	CDT carb
EGT 5	EGT #5		CHT 5	CHT #5		IND	IAT
EGT 6	EGT #6		CHT 6	CHT #6		OAT	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

1

2

3

4

5

6

7

8

9

	Procedure	Example	Comments
	Establish cruise at approx.
	65 to 75% power.
	Pre-lean the mixture to 50°F	I490 370	*For your first flight with the
	estimated rich of peak EGT		EDM, use the method shown
	on any cylinder: _____°		below.
	Wait one minute		Let engine stabilize.
	Tap the LF button	LEAN R	Start LeanFind. (Optionally to
			change to “lean of peak”
			method, hold both STEP and
			LF simultaneously.)
	Lean the mixture—approx.	I520 LF	Flashing cylinder DOT
	10°/second without	Without FF	indicates hottest cylinder and
	pausing—while observing the	I520 I3.8	that LeanFind mode is active.
	display. When there is a 15°F	With FF
	rise in EGT, LeanFind mode
	becomes active.
	Stop leaning when		Flashing cylinder dot &
	a column begins flashing.	I545 SET	column indicates leanest
	You will see LEANEST for two		cylinder. (SET means Set the
		or with
	seconds, followed by:		mixture.) Due to thermal
		Fuel Flow
			inertia this will usually be
		I545 I 2.4
			about -15°F lean of peak.
	If you hold LF, peak EGT will	I560 PK	Captured peak EGT value is
	be displayed while the LF		displayed.
	button is held down.
	Slowly enrich the mixture. the		Peak EGT for best
	temperature will increase,	I560 SET	economy
	returning to peak.		100° rich of peak for best
	Stop enriching at the desired		power
	EGT.		Best	Temperature when
	Best economy	I560 SET	power	column flashes
	Best power	I460 SET	richer	leaner
				best economy
	If you have chosen the Lean	-I5 SET	Only for GAMI injected
	of Peak method, at step 5	OR	engines. When each cylinder
	continue leaning until the last		reaches peak, the cylinder
		-I5 I2.3
	cylinder has peaked.		number will begin flashing.

*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	N		P_
	hottest cylinder		° F
	flashes when	1 2	3 4 5	6 T
	EGT rises 15°	TSO		_
				EGT
	dot	CHT		%
	indicates	500		Limit
	hottest	400		_
	cylinder	300
	temperature	I360 LF
	and "LF"	STEP	EDM-700	LF
	displayed
			JPI
	Page 14		Engine Data Management

Continue leaning slowly without pausing. With a vernier mixture 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.

Leaning Rich of Peak

LEANEST	LEANEST				Cylinder
					number of the
displayed for					LEANEST
two seconds			P_		cylinder flashes
when peak is	N
		° F
found
1	2	3 4	5 6 T	_	Dot indicates
TSO					LEANEST
				_
				EGT	cylinder
CHT				%
450				Limit	Column of the
350
				_	LEANEST
250
					cylinder flashes
I340			SET
					EGT of the
	STEP	EDM-700 LF			LEANEST cylinder
					displayed with the
		JPI
					the word SET
Lean of Peak Leaning with GAMI injectors
For Your Safe Flight					Page 15