Table of Contents
Advertisement
Quick Links
EDM-760/790 Quick Reference Guide
How to use LeanFind (page 15)
Pre-lean
Tap LF
the mixture
button
How to Change Modes (page 9)
EDM-760 enters Automatic indexing mode two minutes after power up
AUTO INDEX:
tap STEP button
parameters
indexed
tap LF button, then STEP button
automatically
(or wait 15 minutes)
tap LF button
LEANFIND:
tap STEP button
procedure
How to ...
interpret CHT trends page 8
lean turbocharged engines page 22
diagnose engine problems page 25
calibrate OAT readings page 39
change from °F to °C page 39, 46
dump data to a PC page 36
Note: Tank size can be entered by holding in the STEP button on power
up of the display.
Lean the
mixture
MANUAL
INDEX:
parameters
indexed when
STEP is tapped
LF
hold LF button
starts
LeanFind
release LF button
reset an alarm page 28
set start up fuel page 31
accumulate total fuel page 32
reset fuel used page 32
set fuel tank capacity page 50
set K factor page 45
PEAK EGT
Enrich to
Stop at
peak or
peak
100° rich of
peak
tap both
STEP and LF
Toggle
simultaneously
include/
exclude
parameter in
release
indexing
buttons
Displays peak
EGT value
Advertisement
Table of Contents
Related Manuals for J.P. Instruments EDM-760 TWIN
Summary of Contents for J.P. Instruments EDM-760 TWIN
- Page 1 EDM-760/790 Quick Reference Guide How to use LeanFind (page 15) PEAK EGT Enrich to Pre-lean Tap LF Lean the Stop at peak or the mixture button mixture peak 100° rich of peak How to Change Modes (page 9) EDM-760 enters Automatic indexing mode two minutes after power up tap both MANUAL STEP and LF...
- Page 2 Specifications Calibration: type K (J CHT avail.) FAA Approved Operating Temperature Range: Indicator TSO & STC Fuel Flow Option STC -40 to 195 o F Temperature Range: Display Size: EGT bar graph: variable 3 1/8 in panel mount EGT, TIT digital: -40 to 2500 o F 3.5 in.
- Page 3 Data capacity: Typical 760/790-6C at 6 seconds up to 15 hours. With F/F and TIT’s it is 10 to 15 hours with a sample rate every 6 seconds. Recording rate: programmable, every 2 seconds to 500 seconds.
- Page 4 Pilot’s Guide EDM-760/790 TWIN Copyright 1999, 2001, 2003, 2005, 2016 J.P. Instruments, Inc. All Rights Reserved Printed in the United States of America J.P.INSTRUMENTS Information: P. O. Box 7033 Huntington Beach, CA 92646 Factory: 3185-B Airway Avenue Costa Mesa, CA 92626...
-
Page 5: Table Of Contents
Table of Contents Section 1 - Introduction Product Features Engine Data Management Benefits of Proper Mixture Control JPI Probes Temperature and Mixture Section 2 - Displays and Controls Displays Modes Buttons Measurement Indexing—without Fuel Flow Option Section 3 - Operating Procedures Diagnostic Testing on Startup and During Flight Modes Automatic Indexing Mode... - Page 6 Section 7 - Start running the downloaded program in the PC, referring to the instructions supplied with that program Section 8 - Personalizing Pilot Programming Fuel Flow Option Programming Fuel Flow Option Programming Procedure Setting Long Term Memory Option Parameters Alarm Limits Fuel Flow Alarm Limits, Units, Fuel Capacity Section 9 -...
-
Page 7: Introduction
Section 1 - Introduction Both the EDM-760 and EDM-790 have the same functionality display on the EDM-760 is a plasma display and the EDM-790 is an LCD display. Note: For the EDM-790, the body is offset to allow for installation clearance. -
Page 8: Product Features
EDM-790 Product Features EDM-760/790 Standard Instrument: Fuel Flow Option: Hands-free, automatic scanning Solid-state pulse generating rotor Bar graph fuel flow transducer LeanFind mode Fuel quantity measured in gallons, Battery voltage kilograms, liters, or pounds ... -
Page 9: Engine Data Management
Engine Data Management The EDM-760/790 Engine Data Management system is the most advanced and accurate piston engine monitoring instrument on the market. Using the latest microprocessor technology, the EDM-760/790 will monitor up to twenty-four critical measurements in your engines, three times a second, with a linearized thermocouple accuracy of better than 0.1 percent or 2°F. -
Page 10: Temperature And Mixture
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. - Page 11 Best Best Peak EGT power economy range range -100 -200 -300 Peak Power Full Rich Rich Lean (Take-off) lean Leaner Mixture 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.
-
Page 12: Displays And Controls
temperature relationship such that one cylinder will reach peak before another. Section 2 - Displays and Controls The EDM-760/790 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: ... - Page 13 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. To change the display of OAT see “Pilot Programming” on page 40. To change the display of engine temperatures see “Changing the Alarm Limits”...
- Page 14 trends, rather than a percentage of red line. You may use normalize in level cruise. To toggle between Percentage and the Normalize views, hold the LF button for three seconds. 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 measurement sequence.
-
Page 15: Modes
CHTs on the bottom (three digits for each engine). Other measurements are displayed in the digital display as described in the subsection “Measurement Indexing—without Fuel Flow Option” on page 12. CHT shown ° F 1 2 3 4 5 6 T 1 2 3 4 5 6 T on calibrated scale... -
Page 16: Buttons
Manual Indexing Mode Just tap the STEP button. Automatic Indexing stops. Each indexed measurement is frozen in the digital display until you manually index to the next measurement by tapping the STEP button. If no button is depressed for 15 minutes, the Automatic Indexing Mode will resume. LeanFind Mode Simply pre-lean, tap the LF button and begin leaning. - Page 17 When an alarm is displayed (“Alarms” are described on page 47), tapping the STEP button will temporarily delete that measurement from the sequence for the next ten minutes. When an alarm is displayed, holding the STEP button until the word appears will delete that measurement from the sequence for the remainder of the flight.
-
Page 18: Measurement Indexing-Without Fuel Flow Option
displayed measurement from the Automatic indexing mode. It has no effect on the displayed measurements in the Manual indexing mode. Measurement Indexing—without Fuel Flow Option The EDM-760/790 steps through the engine measurements in a specific sequence. Listed below is the indexing sequence, measurement description and example of the digital display. -
Page 19: Operating Procedures
TIT 2 Carburetor Temperature Shock Cooling Dot indicates fastest cooling cylinder The display will pause at each measurement for four seconds in the Automatic indexing mode. (The four second indexing rate can be changed. See “Pilot Programming” on page 40.) In the Manual indexing mode, tap the STEP button to advance to next measurement. -
Page 20: Automatic Indexing Mode
mode. And to display specific measurements, use the Manual indexing mode. In both the Automatic and Manual indexing modes the analog display shows a bar graph of EGT and CHT for each cylinder and the TIT, if installed (or Oil temperature, if it is installed and TIT is not installed). -
Page 21: Leanfind Mode-Leaning Rich Of Peak
will index the digital display through the measurement sequence (see “Measurement Indexing—without Fuel Flow Option” on page 12). To exit the Manual indexing mode and return to the Automatic indexing mode, either tap the LF button and then tap the STEP button or wait 15 minutes (see “How to Change Views”... - Page 22 Best Best Last cylinder to power economy peak. Use for range range Lean of Peak leaning with GAMI injectors GAMI First cylinder to -100 spread peak. Use for Rich of Peak leaning Peak Power Rich Lean Full Rich (Take-off) lean Page 16 Engine Data Management...
- Page 23 LeanFind Procedure—Step-by-Step Procedure Example Comments Establish cruise at approx. 65 to 75% power. 1490 Pre-lean the mixture to 50°F *For your first flight with the on the rich side of the EDM-760, use the method estimated peak EGT on any shown below.
-
Page 24: Leanfind Procedure-General Explanation
LeanFind Procedure—General Explanation 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. - Page 25 When LF is activated: To show the progress of the leaning process, the EDM-760/790 selects the hottest cylinder for Reference in the digital display. When LF is activated: To show the progress of the leaning process, the EDM-760 selects the hottest cylinder for reference in the digital display.
- Page 26 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-760/790 and will be displayed as long as you hold the LF button.
- Page 27 In the “lean of peak” method the columns will invert with the first to peak progressing down from the top of the display. The inverted column scale lean past peak is 5° per segment below peak. As you continue to the dot of the each successive cylinder will flash as it peaks.
-
Page 28: Operation For Each Phase Of Flight
Turbocharged Engines The leaning process for turbocharged engines is by reference to the first cylinder or TIT to reach peak. However, the TIT factory red line may limit the leaning process. TIT red line is generally 1650°F, and up to 1750°F in some installations. - Page 29 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. Take-Off, Climb, and Full Throttle Operations Suggested setup: Percentage view Automatic mode Verify: ...
-
Page 30: Common Misapplications
Descent Suggested setup: Percentage view Manual mode Be alert for: CLD: shock cooling alarm is set to -60°F. Average cool rates of -40°F/minute to –60°F/minute are normal, depending on the engine size. Common Misapplications Some of the more common misapplications made by first-time EDM- 760/790 users are presented here in an attempt to help you avoid similar problems. -
Page 31: Diagnosing Engine Problems
Section 7 - Diagnosing Engine Problems Normal Engine Limits The follow chart lists typical normal measurement values that you will observe for most general aircraft engines. Measurement Normal range Comments EGTs in Cruise 1350°F under 200 HP 1550°F high performance ... - Page 32 Engine Diagnosis Chart The following chart will help you diagnose engine problems in your aircraft. (Views are Percentage views). Notice that there is always one CHT that is shown hotter than the others. Display Symptom Probable Recommende Cause d Action 75°...
- Page 33 Display Symptom Probable Recommended Cause Action EGT and Dirty fuel Check injectors CHT not injectors or and plugs. Non- uniform fouled plugs. uniformity is normal for carbureted engines Decrease Decrease in Check for change in EGT for airflow into the in manifold all cylinders induction system.
-
Page 34: Alarms
Display Symptom Probable Cause Recommended Action Decrease in Check EGT for one compression. compression. cylinder at low RPM Pre-ignition, Full rich and Sudden off reduce power. scale rise for Normalize view, Change to any or all Percentage view. cylinders or failed probe Check probe Loss of peak Poor ignition or... -
Page 35: Pre-Ignition And Detonation
returns to within normal limit(s), the display will stop flashing the alarm. If your installation includes a separate panel mounted alarm warning enunciator light or audible warning, it too will be activated. There is no alarm for the individual EGTs because the temperature values can assume different ranges depending on the flight configuration (run up, climb, cruise). -
Page 36: Data Logging
avgas contaminated by jet fuel. Fuel additives, such as lead, boost the octane rating and slow down the combustion process, producing an even pressure to the piston. Pre-ignition is caused by hot spots in the cylinder. Ignition occurs prior to the spark plug firing. - Page 37 in the digital display in either the Automatic or Manual indexing modes or during the pilot programming procedure. In the FF (Fuel Flow) position only fuel flow measurements are displayed in the digital display in either the Automatic or Manual indexing modes or during the pilot programming procedure.
- Page 38 tanks. to the tabs. If some additional fuel is added to the auxiliary tanks, you will input this next when .0 GAL is displayed FILL (not available) Topped the Topped both the main main tanks. and auxiliary tanks. FILL Did not top, but added additional fuel to the aircraft, or removed fuel from the aircraft.
-
Page 39: Fuel Management
Resetting “USED” Every time you inform the EDM-760/790 that the aircraft is refueled, the amount of fuel used is set to zero, unless the instrument is programmed to accumulate. The display of fuel used pertains only to the fuel used since the last time you informed the EDM-760/790 that the aircraft was refueled. -
Page 40: Measurement Indexing-With Fuel Flow Option
Measurement Indexing—with Fuel Flow Option The EDM-760/790 steps through the engine measurements in a specific sequence. Listed below is the indexing sequence, measurement description and example of the digital display. The display will pause at each measurement for a few seconds in the Automatic indexing mode. In the Manual indexing mode, tap the STEP button to advance to next measurement. -
Page 41: Long Term Memory
MPL, MPP) 1340 T, A EGT, left, CHT, right. Dot EGT, CHT 1430 indicates cylinder 1370 T, A TIT, Turbine Inlet 1450 Temperature T, A Oil Temperature 1450 T, A Only one of these three options TIT #2 Second 1460 may be installed in the aircraft Turbine Inlet T 12... -
Page 42: Transferring Data From The Edm-760 To A Laptop Pc
next data record by tapping the LF button twice. You will see the word SNAP within the next six seconds, indicating a data record has been marked. Tap the STEP button to return to the Automatic indexing mode. Recording begins when EGTs are greater than 500°F or “snap” is requested. - Page 43 Serial Cable supplied with your EDM If no serial port is found on your newer laptop, you will need an option which allows direct download of flights to a USB Thumb drive. This can be accomplished with a JPI Download box. This allows the direct connection using the serial cable to a USB Thumb Drive eliminating having to bring your laptop to the airplane.
- Page 44 NEW will transfer only data newly recorded since you last saved your data. ALL will transfer all the data that is in the EDM-760 memory. In either case, no data will be erased from the EDM-760. 7. Tap the STEP button to begin the transfer process. The display shows the percentage of memory remaining to be transferred.
- Page 45 Section 10 - Start running the downloaded program in the PC, referring to the instructions supplied with that program. For Your Safe Flight Page 39...
- Page 46 Section 11 - Personalizing Pilot Programming You can program the automatic indexing rate (1-9 seconds or 0 = don’t auto-index), the temperature display (°F or °C) and the EGT resolution (1 or 10°). To start the Pilot Programming Procedure, simultaneously hold the STEP and LF buttons for five seconds.
- Page 47 OAT+0 OAT-10 This step will be normally be T, A skipped. See step above. OAT 10 Adjust the indicated temperature up or down by up to 10°. For example, adjust the OAT upward 3°. OAT 3 T, A Y—Yes—sets the digital display to 1?N ...
- Page 48 Using a Factory Original TIT Probe If your aircraft is using the factory original TIT probe and gauge, you will be required to calibrate the EDM-760/790 for that probe. The factory original TIT probe must be a type K and the leads must be wired red-to- red and yellow-to-yellow.
- Page 49 Fuel Flow Option Programming Fuel Flow Parameters Three additional parameters may be set by the pilot when the Fuel Flow Option is installed: K Factor—the fuel flow transducer calibration constant. Accumulate—default is OFF: reset the fuel used to 0 every time you inform the EDM-760/790 that the aircraft was refueled.
- Page 50 Fuel USED shown by Actual fuel used by EDM-760/790 topping tanks Flight USD L USD R filled left filled right Total 2. Total the EDM-760/790 fuel used and the actual fuel used for each tank. 3. Record the current K factor here left_________ right_________ and in the table below.
- Page 51 Every time you fine tune the K factors, record the measurements here: Right Engine EDM- actual Current K New K factor = x / 760 fuel fuel used factor Date used Left Right Left Right Fuel Flow Option Programming Procedure Setting the K factor...
- Page 52 11. Hold STEP and LF buttons simultaneously for five seconds to exit this procedure. Accumulate Total—Trip Total Select “no” if you wish to display total fuel used since the last time you informed the EDM-760/790 that the aircraft was refueled. Select “yes” to display total fuel used for an extended trip with multiple fuel stops.
- Page 53 moves to the next character. To Save the Aircraft ID, Hold both STEP and LF for 5 sec. Tap STEP button to exit the procedure. Alarm Limits Factory Set Default Limits JPI conservatively sets the default alarm limits below Lycoming and Continental recommendations.
- Page 54 To start the alarm limit procedure, after power up, wait until the EDM- 760/790 completes its self test and is in the Automatic or Manual indexing mode. If in doubt, tap the STEP button a few times. Then follow the steps depicted here: Hold both Hold both Tap STEP...
- Page 55 Changing the Alarm Limits Procedure STEP button sequences to next item LF button sequences through Description these values FAC? FAC? Restore factory defaults? REV X.XX Firmware rev. number (momentary) ENG F ENG C Select F or C degrees for all engine temps. You must also change the alarm limits to °F or °C.
- Page 56 Main tank capacity, in units selected MAIN=100 AUX? AUX? Y Y—Yes—aircraft has auxiliary tanks Auxiliary tank capacity AUX=0 Alarm limit in minutes for low time in MIN=45 tanks Alarm limit for low fuel quantity in REM=10 tanks, in units selected ...
- Page 57 Main Tank Capacity Enter the total capacity of the main tanks in the fuel flow units selected. If you have tank tabs (but no auxiliary tanks) and sometimes fill only to the tabs, set the main tank capacity to the capacity up to the tabs. Auxiliary Tanks If you do not have auxiliary tanks or tank tabs, answer “No.”...
- Page 58 Format Baud rate NMEA-183 4,800 This is the format for most handheld (Marine GPS receivers. Loran must have Navigation Data sentences RMA & RMB. GPS must Format) have sentences RMB & RMC. Aviation Data 9,600 “Output sentence type 1” Req’d Format sentences: A, B, C, D, E, I and L first char id byte.
- Page 59 GPS Interface Diagnostics Measurements REQ, RES, & No communications from GPS receiver to EDM-760. Possibly no connection or MPG are all missing from the aircraft GPS is off. scan. NO - COM message and Communications are received by EDM- 760/790 and the Auto-Protocol setup is measurements REQ, RES, &...
- Page 60 Navigation Data Ports for GPS Comm (These ports are completely independent of the EDM-760/790 serial data output port.) Navigation Data (output of GPS; input to EDM-760/790) Compatible with RS-232, TTL, RS-423, RS-422 SDA. Serial data format 8 data, 1 start, no parity. Baud rates: 1,200, 4,800, or 9,600 depending on the GPS data output format.
- Page 61 Section 14 - Reference Reading You may wish to know more about the effect of engine operations on EGT and CHT. The reading list below provides general overviews as well as original references on topics that may be of interest. General Overview These references are readily available to pilots and provide a readable source of general technical information.
- Page 62 3185-B Airway Avenue (800) 345-4574 Costa Mesa, CA 92626 jpinstruments.com Page 56 Engine Data Management...
- Page 63 Limited Warranty J.P. Instruments, Inc. (JPI), warrants all parts in your new EDM-760/790 to be free from defects in material and workmanship under normal use. Our obligation under this warranty is limited to repair or exchange of any defective part of this unit if the part is returned, shipping prepaid, within three years for electronics and one year for probes from the date of original purchase.
- Page 64 Index Accumulate, 40, 44 CAL ERR, 13 total, 32 Calibration, 13 Adapter probe, CHT, 24 K-factor, 42 Adding fuel, 31 TIT, factory original, 41 Adjusting Capacity, fuel tank, 30 K-factor, 42 CARB?, 49 TIT, factory original, 41 Carburetor, 50 Alarm limits ice, 26 changing, 46 Celsius...
- Page 65 GPS formats, 50 Exclude measurements, 13 ports, GPS, 53 Exhaust leak, 27 Data logging EzCapture™, 35 manual, 29 Data output serial port, 30 Date set, 45 Factory default alarm limits, 45 Day set, 45 Factory original TIT probe, 41 Default alarm limits, 45 Fahrenheit Defueling, 31 display indicator, 6...
- Page 66 GAMI, 14, 19, 20 Garmin, 51 Gasket probe, 24 LBAT, 48 Gasket, manifold, 27 Leak GPH, 33 manifold, 27 Lean of Peak, 19 comm settings, 44 Default, 49 constant, 40 Lean of Peak Leaning, 19 data formats, 50 Leanest cylinder, 16 data ports, 53 LeanFind GPS-C, 40...
- Page 67 Programming, 39 alarm limits, 45 data recording, 45 Nautical miles per gallon, 34 fuel flow option, 42 Navigation data formats, 50 NEW, 35, 37, 40 NMEA-183, 51 NO COM, 52 NO SIG, 52 Range, normal temperature, 24 NO WPT, 52 Rate Normal engine limits, 24 baud, 53...
- Page 68 Long Term Memory Option, 45 Shadin Miniflow, 51 Shock cooling, 12, 14, 23, 24, 34 Valve SNAP, 35 lifter, 25 Spark plug stuck, 25 fouling, 7, 21, 25, 26 Vapor, 27 Specifications, 2 View Startup change diagram, 10 diagnostics, 13 normalize, percentage, 7 fuel, 30 Voltage, 11, 33...
- Page 69 For Your Safe Flight Page 63...
Need help?
Do you have a question about the EDM-760 TWIN and is the answer not in the manual?
Questions and answers