J.P. Instruments EDM 930 Primary Pilots Guide - Manual (Page 16)

For Your Safe Flight Page 11
Display Symptom Probable Cause Recommended
Action
Slow rise in
EGT. Low
CHT Burned exhaust
valve. CHT is low
due to low power
output. Have compression
checked.
High CHT on
cylinders on
one side of
engine Obstruction under
cowling. Check for improper
installed baffling,
cowl flap
misalignment or bird
nests.
Rapid rise in
CHT of one
cylinder Detonation. Reduce power.
Sudden off
scale rise for
any or all
cylinders
Pre-ignition
Normalize view
or failed probe
Full rich and reduce
power.
Change to Standard
view
Check probe
(no picture)
Loss of peak
EGT Poor ignition or
vapor in fuel
injection system. Have magneto tested.
(no picture)
Decrease in
peak or flat
EGT response
to leaning
process Detonation. Usually
the result of 80
Octane fuel in 100
Octane engine. Enrich mixture,
reduce power and
relean mixture.
Repeat to find power
setting where normal
peak is obtained or
run rich.
Below 10,000
ft. full throttle
causes EGTs
to rise Weak or defective
mechanical fuel
pump. Apply booster pump.
If EGTs drop, replace
fuel pump.
CHT more
than 500°,
EGT normal.
Adjacent EGT
may be low Leaking exhaust
gasket blowing on
CHT probe. Look for white
powder around
cylinder to determine
leak area.