J.P. Instruments EDM 930 Primary Pilots Guide User Manual
Page 58

For Your Safe Flight
Page 53
Troubleshooting the EDM
Common Misapplications
Problem
Situation
Correction
Display freezes or may
be incorrect
A power transient
could cause the
processors to
malfunction
Recycle the power to the
EDM
LeanFind finds a
“peak” too soon
Failure to pre-lean
before performing
LeanFind or stopping
while leaning
Continue to lean without
stopping
Leaning too slowly
Lean more rapidly
Peak not found during
LeanFind
Lean Find not
activated or stopping
while leaning
Lean at the speed of
approximately 10°F per
second
Off-scale EGT
columns, too high or
low
Off-scale EGT column
readings. EDM in the
Normalize view (blue
scales)
The higher sensitivity of
the Normalize view can
quickly go too high or low
off-scale with only small
changes in EGT.
First cylinder to peak
is not the hottest
This is normal. The first to cylinder peak is not
necessarily the hottest
EGTs rise during
single magneto check
This is normal, due to incomplete combustion
persisting longer
EGTs not uniform
during low power
operation
This is normal. Fuel and air distribution is not
optimal at low power settings
Diagnostic Testing on Startup and During Flight
When your EDM is first turned on it tests internal components,
calibration and integrity of the probes. Most alarms are disabled until the
engine has been started.
During flight, probes are constantly checked for inconsistent or
intermittent signals. A faulty channel or probe encountered during start-
up or during flight will be deleted from the sequence, producing a
missing column or blank digital data.