J.P. Instruments EDM 900 User Manual

Pilot’s Guide

Engine Data Management

EDM-900

Primary

TSO/STC

Copyright  2011 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] Fax [phone]

www.jpinstruments.com
www.JPITech.com

www.buyJPI.com

Printed in the United States of America Rev A

Last printed

For Your Safe Flight Page 1

Table of Contents

Section-1 Getting Started 4

View Angle 4
Rotation 6
Fuel Flow Computer Basics (independent of fuel quantity) 6
Display Screen Basics 7
Horizontal Display Mode 7
Vertical Display Mode 8
Remote Annunciate Light Basics 8
RPM and MAP Display Basics 9
Linear Bar Graph Display Basics 9
Scanner® Information Area 10
LeanFind Basics 11

Section 2 - Interpreting Data 12

Operation for each Phase of Flight 12
Typical Normal Measurements 14

Section 3 - Displays and Controls 17

Control Buttons 17
Scanner Displays 19
Additional Displays Hobbs, Revisions, and Alarm Limits 21
Dimming the Display 22

Section 4 - Operating Modes 22

Automatic Mode 22
Manual Mode 23

Section 5 - LeanFind 24

LeanFind Procedure—General Explanation 28
Expanded Leaning Procedures 31
Common Misapplications 32

Section 6 - Fuel Flow Operation 33

Fuel Management 33
Start Up Fuel 34
Resetting ‘USD’ 35
Trip Mode (Accumulate Trip Totalizer) 35

Scanner Fuel Flow Display Select 35
Section 7 - Alarms 36
Section 8 - Memory and Data Download 37

Downloading Data from the EDM 37

Transferring data from the USB Flash Drive to a PC 38
Section 9 - First Time Setup and Customization 38
Section 10 - Adjusting Manifold Pressure & %HP 41

Adjusting the HP Constant for Rich of Peak Operation 41

Adjusting the MAP 41

Adjusting the HP Value 42
Section 11 - Programming the Fuel Flow 42

Page 2 Engine Data Management

Fuel Flow K factor 43

Programming Trip Mode 45

Setting the GPS Com Format 45

Troubleshooting the EDM 47

Diagnostic Testing on Startup and During Flight 47

Diagnostic Messages 47
Section 12 - Appendices 48

Shock Cooling (CLD) 48

List of ALL messages in EDM-900 49

Navigation Data Formats 50

Navigation Data Ports for GPS Comm 50

Interface connections to selected GPS models 50
Section 13 - Technical Support 51

For Your Safe Flight Page 3

Section-1 Getting Started

This is a summary of basic operation. Detailed descriptions of all
operations appear later in this Pilot’s Guide.

EDM-900 primary instrument has preset alarm limits and
cautionary ranges per the POH (user cannot change them)
typically for the following measurements of: oil temperature, oil
pressure, fuel pressure, fuel quantity, cylinder head temperature,
turbine inlet temperature, manifold pressure, and RPM.

Note: Fuel quantity gauges must be calibrated to the aircraft and
will not be functional until the fuel calibration process has been
performed.

View Angle

The best view angle for the pilot is in the horizontal mode with the
buttons on the bottom. The best Portrait mode is with the buttons
on the right.

View angles are per the table below:

Horizontal Left 65 Degrees
Viewing Right 65 Degrees
angle Vertical Left 60 Degrees

Right 50 Degrees

Page 4 Engine Data Management

List of abbreviations and acronyms

Message Area

Alarm

Abbreviation

Engine Oil Temperature

Gauge Function

Primary Primary

Engine rotational speed RPM xxxx
Engine Manifold Pressure MAP xx.x in hg
Engine Cylinder Head Temp CHT2 xxxoF

O-T xxxoF

Engine Oil Pressure O-P xxxoF
Fuel Pressure F-P xx PSI
Fuel Flow to engine F-F xx.x GPH

Comp. Discharge Temp. CDT xxxoF
Turbine inlet Temp. Left side TIT-L xxxxoF
Turbine Inlet Temp. Right side TIT-R xxxxoF
Single Turbine Inlet Temp. TIT xxxxoF

Non-Primary Non-Primary

Exhaust Gas Temp. EGT2 xxxxoF
Shock Cooling of CHT CLD xxo/MIN
Differential Temp. of EGT DIF xxoF
Bus Voltage Volts xx.x
Amperage Load AMPS xx
Outside Air Temp. OAT xxoF
Estimated Time to Empty Est. T to E xx:xx H:M
Fuel used to date USED xx.x GAL
Estimated Remaining fuel Est. REM xxGAL

Estimated Fuel required to Waypoint Est. WP REQ xx GAL
Estimated Fuel Remaining at

Waypoint
Nautical Miles per Gallon ECON xx.x MPG
Brightness, Dim control DIM/BRT

Est. WP RES xx GAL

For Your Safe Flight Page 5

Rotation

Holding the step button in for 5 seconds, with the engine OFF, will
produce the gray arrow. This arrow can be rotated to a new up position
by tapping the LF button and then the STEP button. If for some reason

you chose the one bad angle (Landscape looking up from the
buttons), return the instrument to JPI and JPI will rotate the
screen.

Fuel Flow Computer Basics (independent of fuel quantity)

The fuel flow computer tracks the fuel flowing to the engine and
computes various values based on this. At installation, then each time
you refuel the aircraft, you must inform the EDM about how much
useable fuel is onboard. This is done via the REFUEL function.
See page 33 for detailed information

Control Button Basics

Four operating buttons control all functions of the EDM. These buttons
change labels depending on the current state of the EDM.

Page 6 Engine Data Management

Display Screen Basics

The display screen is arranged into three sections. The top left is the
MAP and RPM section. The bottom left is the Scanner® section or
message area. On the right side are the horizontal primary strip gauges.
Non-Primary gauges have a digital read out only. The instrument ranges
and alarm limits are configured to match those of your aircraft POH when
the EDM is set up as a Primary instrument. TIT column is to the right

of the last EGT/CHT when applicable.

Horizontal Display Mode

For Your Safe Flight Page 7

Vertical Display Mode

Remote Annunciate Light Basics

The Remote Annunciator Light ‘RAL’
provides notification that an alarm is present
in the display, for all Primary gauges. Upon
power up, the RAL shows Red and yellow
indicating it is functional. Before each flight,
confirm that it is functional. Non-functioning
RAL must be repaired before flight.

Remote
Annunciator Light
(RAL)

Page 8 Engine Data Management

Horizontal mode Vertical mode
RPM and MAP Display Basics

In the vertical mode to the right and the
Horizontal mode above MAP (Manifold Pressure)
and RPM (Revolutions per Minute) are shown.
Operations exceeding red line cause the digital
value to turn red or yellowwith the RAL coming
on and a digital value in the Scanner message
area.

Linear Bar Graph Display Basics

The Bar Graphs section contains dedicated bar graphs with digital
display. An example is shown here. Pointers move horizontal left to right
showing value changes and digital readouts turn red
when primary exceedances occur. Non primary

functions flash white.

Horizontal mode Vertical mode

For Your Safe Flight Page 9

Scanner® Information Area

The Scanner® Information Area provides expanded information in the form of
alpha-numeric messages, parameters and calculations. In Auto-Scan,
parameters will ‘scan by’ once every 4 seconds (default). This rate can be
changed in Pilot Programming Mode. Tap the STEP button for ‘Manual’ selection
of any parameter. Parameters for the installed options will be displayed. To start
the automatic scan tap LF and then STEP.

DISPLAY PARAMETER DESCRIPTION

EGT 1436 CHT 382 EGT/CHT

TIT 1580oF TIT Single Turbine Inlet Temp.

TIT-L and -R 1490

o

F

Oil-T 204oF OIL TEMP Oil temperature in degrees F

Oil-P 64 PSI OIL PRES Oil pressure in psi

F-P16 PSI FUEL PRES. Fuel pressure in psi

F-F 2.7GPH FUEL FLOW Fuel flow in GPH

CLD 75oF

VOLTS 13.9 BATTERY Battery/Bus voltage

AMPS -6 Amperage Set up per the specific aircaraft

OAT 23oF OAT Outside air temperature F or C

DIF 40oF DIF Hottest minus coldest EGT

CRB 56oF CRB

CDT 145oF CDT

IAT 105oF IAT Induction Air Temp

Est. REM 68.0GAL

WP REQ 12.7 GAL

Est. WP REM 63 GAL

ECON 9.8 MPG

EST. T to E 04:32
H:M

GPH 15.0 GPH

USD 7.2 GAL FUEL USED Actual fuel used by the engine

FUEL-P 64 PSI FUEL PRES Fuel pressure in PSI

TIT-L, TIT -R

SHOCK

COOL

FUEL

REMAINING

FUEL

REQUIRED

FUEL

RESERVE

Nautical

MILES PER

GALLON

Estimated

Time to

Empty

FUEL FLOW

RATE

Shows successive pairs of EGT &
CHT per STEP tap.

Two Turbine Inlet Temp. Left and
Right engine side

CHT cooling rate (deg/min)

Carburetor Air Temp (only allowed if
IAT not present)
Compressor Discharge Temp (only
allowed if CRB not present)

Calculated fuel remaining on board
based on what the pilot put in as
maximum.
Calculated fuel required to reach
waypoint or destination (GPS
interface must be corrected)
Calculated fuel reserve at waypoint
(GPS interface must be correct)

Calculated fuel miles per units
(GPS interface required)

Calculated time remaining to fuel
exhaustion in Hours and Minutes at
present power.
Actual fuel flow rate in Gallons per
hour

Page 10 Engine Data Management

LeanFind Basics

Simply pre-lean, tap the LF button
(Lean Find) and begin leaning. The
EDM will assist you in finding the first
cylinder to peak. This example is for
Rich of Peak, ROP. See page 24 for
a more detailed description of
leaning. Press LOP to exit the ROP
mode and enter the LOP mode.

1. Establish cruise at approximately 65 to 75% power and pre-lean the

mixture to 50°F estimated rich of peak EGT on any cylinder.

2. Wait about 30 seconds, then tap the LF button.

3. Begin leaning the mixture smoothly without stopping. Turn a vernier

about ¼ turn per second; retract a non-vernier or quadrant lever so
that EGT rises about 10°F per second.

4. Stop leaning when you see LEANEST for two seconds, followed by—

for example—
temperature of the first EGT to peak and the right number is the
current fuel flow.

5. Now tap the PEAK button to display the EGT difference from peak

which is very useful for setting desired degrees below peak.

6. Slowly enrich the mixture noting that the EGT difference diminishes

as EGT climbs back to peak, followed by it going minus again. Stop
enriching at the desired EGT difference (such as ‘EGT -75’).

7. You can also see what the peak EGT was by holding the PEAK

button.

8. Tap STEP to

exit the Lean
Find Mode.

EGT

1449FF14.7 The left number is the current

For Your Safe Flight Page 11

Section 2 - Interpreting Data

Operation for each Phase of Flight

(Worth adding to your run-up checklist)

Suggested setup:

 Setengine to run-up RPM

Engine
Run-Up

Take-Off,
Climb, and
Full
Throttle
Operations

Normalize view:

 Manual mode

Verify:

 Uniform rise of about 50°F in all EGTs in single

magneto operation.

 Uniform rise of EGTs with application of the mixture

control.

Be alert for:

 unusually low voltage (less than nominal battery

voltage)

 cold OIL and normal oil pressure
 abnormally high CHT

 Large drop in EGT on one cylinder in single magneto

operation—may be fouled spark plug.

Suggested setup:

 Standard view
 Automatic mode

Verify:

 EGTs and CHTs consistent with past climbs. EGTs

should be in the 1100 to 1300°F range (100° to 300°F
cooler than cruise) due to fuel cooling.

Be alert for:

 High EGT in one cylinder, 300°F above the others may

indicate plugged injector or leaking manifold gasket on
a carbureted engine. At high density altitude an overly
rich mixture can significantly reduce engine power.

 If all EGT columns go off scale to the top of the

column, be sure you are not in Normalize view, as
indicated by the symbol NRM above the Scanner®
section.

Page 12 Engine Data Management

Cruise

Descent

After the engine is warmed up, use LeanFind to lean the
mixture.

Suggested setup:

 Normalize view
 Automatic mode

Be alert for:

 Uneven EGTs (injected engines). Make fine

adjustments to throttle, then RPM, then mixture to
level the display columns.

 Abnormal patterns of EGTs and CHT. (see Engine

Diagnosis Chart on page 15).

Suggested setup:

 Standard view
 Manual mode

Be alert for:

 CLD: shock cooling alarm is set to -60°F. Average

cool rates of -40°F/minute to -50°F/minute are normal,
depending on the engine size.

For Your Safe Flight Page 13

Typical Normal Measurements

The following chart lists typical normal measurement values that you will
observe for most general aircraft engines. Your particular engine’s
ranges may not fall within these values.

Measurement Normal range Comments

EGTs in Cruise 1350°F

1550°F

EGT span (DIF) 70 to 90°F

120 to 150°F

TIT 1600°F average
CHTs 350°F (OAT 60°F)

410°F
CHT span 50 to 70°F
OIL T 200°F

OIL P 30 to 60 psi
FUEL P (injected) 14 to 18 psi
FUEL P (carbureted) 0.5 to 8 psi
Shock cooling* -40°/minute

-55°/minute

-200°/minute

 under 200 HP engines
 high performance engines
 (EGT should drop 200°F when

full throttle is applied)

 fuel injected engines
 carbureted engines
 100° higher than EGT
 normally aspirated engines
 Turbocharged engines
 100° with gasket probes
 oil cooler thermostat typically

opens at 180°F

 varies with aircraft type
 varies with aircraft type

 tightly cowled engines
 Bonanza
 helicopter

* Maintain a cooling rate magnitude of less than -50°/minute. You will find

that the cylinder with the greatest shock cooling may shift from front
cylinders (during climb out) to the rear cylinders (during descent ).

Page 14 Engine Data Management

Engine Diagnosis Chart

The following chart will help you diagnose engine problems in your
aircraft.

Display Symptom Probable

Cause

TIT ~100°
higher than
EGTs

75° to 100°
EGT rise for
one cylinder
during flight

EGT Increase
or decrease
after ignition
maintenance

Loss of EGT
for one
cylinder.
Engine rough

Loss of EGT
for one
cylinder; no

digital EGT

Decrease in
EGT for one
cylinder

This is normal

Spark plug not
firing due to fouling,
faulty plug, wire or
distributor.

Improper timing:
high EGT 
retarded ignition;
low EGT 
advanced ignition.

Stuck valve. Other
cylinders are okay.

Failed probe
or
failed wire harness.

Intake valve not
opening fully; faulty
valve lifter.

Recommende

d Action

Enrich mixture to
return EGT to
normal. Have
plugs checked.

Check EGT for
each magneto to
determine any
uneven timing.

Have valve train
checked.

Swap probes to
determine if probe
or wire harness is
bad.

Have valve lifter or
rocker arm
checked.

Increase in
DIF at low
RPM

EGT and
CHT not
uniform

Decrease in
EGT for all
cylinders

Low compression
(blow by) in
cylinder

Normal for
carbureted
engines. Dirty fuel
injectors or fouled
plugs.

Decrease in airflow
into the induction
system. Carb or
induction ice.

Check
compression.

Check injectors
and plugs.

Check for change
in manifold
pressure.

For Your Safe Flight Page 15

Display

(no picture)

(no picture)

Symptom Probable

Cause

Slow rise in
EGT. Low
CHT

High CHT on
cylinders on
one side of
engine

Rapid rise in
CHT of one
cylinder

Sudden off
scale rise for
any or all
cylinders

Loss of peak
EGT

Decrease in
peak or flat
EGT
response to
leaning
process

Below 10,000
ft. full throttle
causes EGTs
to rise

CHT more
than 500°,
EGT normal.
Adjacent EGT
may be low

Burned exhaust
valve. CHT is low
due to low power
output.

Obstruction under
cowling.

Detonation. Reduce power.

Pre-ignition
Normalize view
or failed probe

Poor ignition or
vapor in fuel
injection system.

Detonation.
Usually the result
of 80 Octane fuel
in 100 Octane
engine.

Weak or defective
mechanical fuel
pump.

Leaking exhaust
gasket blowing on
CHT probe.

Recommended

Action

Have compression
checked.

Check for improper
installed baffling,
cowl flap
misalignment or bird
nests.

Full rich and reduce
power.
Change to Standard
view
Check probe

Have magneto
tested.

Enrich mixture,
reduce power and
relean mixture.
Repeat to find power
setting where normal
peak is obtained or
run rich.

Apply booster pump.
If EGTs drop,
replace fuel pump.

Look for white
powder around
cylinder to determine
leak area.

Page 16 Engine Data Management

Section 3 - Displays and Controls

The EDM monitors engine temperatures, pressures and voltages, assists
in adjusting the fuel/air mixture, and helps diagnose engine malfunctions.
There are multiple components of the user interface:

 Four front panel operating buttons below the bottom of the display.
 RPM and MAP display in the upper left corner of the display
 Scanner analog display including cylinder number and index square

in the lower left corner of the display

 Scanner digital display for numeric readouts and messages at the

bottom left

 Bar graph displays on the right half of the display

Control Buttons

Four operating buttons control all functions of the EDM. These buttons
may change labels depending on the current operating mode of the EDM.
The term tap is used to denote pressing a button momentarily. The term
hold is used to denote pressing and holding a button for five seconds or
longer. Button layout is shown below:

1st Button

 In the Automatic mode, tapping the STEP button stops Scanner auto-

sequencing and changes to Manual mode. Each tap of the STEP
button then displays the next measurement in the sequence. Holding
the STEP button sequences in reverse order.

 In the LeanFind mode tapping the EXIT button will terminate the

LeanFind mode and change to the Automatic mode.

 In the Program mode tapping the NEXT button will advance to the

next item.

2ndButton

 In Automatic or Manual modes, tapping the LF button will activate the

LeanFind mode.

For Your Safe Flight Page 17