J.P. Instruments EDM 960 Twin Pilots Guide - Manual (Page 57)

For Your Safe Flight Page 52
Troubleshooting the EDM-960
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 the unit performs several tests on
internal components, calibration and integrity of the probes. Typically,
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.