J.P. Instruments EDM 960 Twin Pilots Guide - Manual (Page 13)

For Your Safe Flight Page 8
Engine Diagnosis Chart
The following chart will help you diagnose engine problems in your
aircraft (note: only one engine is shown).
Display Symptom Probable
Cause
Recommended
Action
TIT ~100° higher
than EGTs This is normal
75° to 100° EGT
rise for one
cylinder during
flight Spark plug not firing
due to fouling, faulty
plug, wire or
distributor. Enrich mixture to
return EGT to normal.
Have plugs checked.
EGT Increase or
decrease after
ignition
maintenance Improper timing: high
EGT
→ retarded
ignition; low EGT
→
advanced ignition.
Check EGT for each
magneto to
determine any
uneven timing.
Loss of EGT for
one cylinder and
Engine rough Stuck valve. Other
cylinders are okay. Have valve train
checked.
Loss of EGT for
one cylinder and Failed probe
or
failed wire harness.
no digital EGT
and/or bad probe
message.
Swap probes to
determine if probe
or wire harness is
bad.