FAA Approved Installation Manual for the EDM-960 system
Report No 909
Primary Engine Data Management System
Page 13 of 45 Rev C
Date 12-12-12
12. Wiring Markings
The EDM-960 is supplied with special Teflon insulated Chromel Alumel factory assembled wiring harness
configured for the correct number of cylinders. The wire harness is marked E1= EGT-1, C1= CHT-1, etc.
NOTE:
Unlike most other EGT & CHT installations the probe wire length is not critical and should be trimmed to any
length as required for a clean installation. Do not extend the thermocouple wire with copper wire.
13. Exhaust Gas Temperature Probe (EGT) Installation
Use the J2 connector harness 700700 or 700702 labeled E1 through E4 or E6. Remove the existing EGT gage and
Probe. Replace with JPI probe M-111 in all exhaust stacks.
The Model M-111 Probe will fit any engines where
the existing holes in the exhaust stack are 1/8" to
1/4" in diameter. If no hole exists, it will require the
drilling of a 1/8" diameter hole and ream to fit. It is
important that each probe be mounted the same
distance from its exhaust stack flange. A nominal
distance of 2 to 4 inches from the exhaust flange is
recommended. If the recommended distance is
impractical because of obstructions, slip joints or
bends in the exhaust system then position the
probes a uniform distance from the flange as space
permits. Do not mount probes in slip joints. Be
certain to locate all holes BEFORE drilling to
ensure that nothing interferes with the probe,
clamp, screw or wire. Careful matching of probe
position will provide best temperature readings.
Insert the probe in the exhaust or previously drilled hole so that the tip of the probe is in the center of the exhaust
stream. Tighten the stainless steel clamp to a torque of 45 in/Lbs. Cut off the excess strap close to the screw.
Position probe
in approximate
center of
exhaust
Probe
Clamp
Thimble
note orientation of
slot
Seal Washer
RADIAL ENGINE EGT
Radial engine exhaust, require a larger EGT clamp (supplied) to fit the 2.5 inch exhaust pipe. The EGT probe is
installed in the same fashion as a Lycoming or Continental engine and should be placed between the exhaust pipe
flange and the accumulator at a distance of 2 to 3 inches form the engine exhaust flange. Cylinder head
temperatures are measured with a spark plug gasket type probe placed under the front sparkplugs. Front spark
plugs will read 15 to 20 degrees cooler than the rear plugs. Refer to the engine manufactures recommended
location. Do not route the EGT/CHT harness in with the ignition harness. Do not extend the yellow thermocouple
leads with copper wire.
2" to 4"
EGT probe
Drill no. 40
pilot hole,
then no. 30
hole.
CHT probe
e
x
h
a
u
s
t
s
ta
c
k
