J.P. Instruments EDM 740 Pilots Guide - Manual (Page 37)

For Your Safe Flight Page 37
Pre-ignition is caused by hot spots in the cylinder. Ignition occurs prior
to the spark plug firing. The EDM depicts pre-ignition as a sudden red
line of the EGT on the analog display. This may occur in one or more
cylinders. The affected cylinder column(s) will flash while the digital
display will show an EGT higher than 2000°F. At this temperature
pre-ignition will destroy your engine in less than a minute unless you
take immediate corrective action.
Section 4 - Fuel Flow Option Operation
Fuel Management
Without a means of measuring accurate fuel flow, you must rely on the
aircraft fuel gauges or total time of flight. Aircraft fuel gauges are
notoriously inaccurate (they are only required by the FAA to read
accurately when displaying empty). Determining fuel consumption by
multiplying time of flight by estimated flow rate is, at best, an
approximation, and assumes a constant fuel flow rate for each phase of
flight. However, the EDM Fuel Flow Option uses a small, turbine
transducer that measures the fuel flowing into the engine. Higher fuel
flow causes the transducer turbine to rotate faster which generates a
faster pulse rate. Because the transducer turbine generates thousands of
pulses per gallon of fuel, it can measure with high resolution the amount
of fuel that flows into the engine. Prior to engine start you inform the
EDM Fuel Flow Option of the known quantity of fuel onboard, it
subsequently tracks all fuel delivered to the engine.
IMPORTANT: For EDM fuel calculations to be
accurate, it is mandatory that you inform the EDM of
the correct amount of usable fuel onboard the aircraft
and confirm proper operation of the fuel flow transducer
prior to and during flight. Do not rely on fuel flow
instruments to determine fuel levels in tanks. Refer to
original fuel flow instrumentation for primary fuel
management information.