G Series Data:
G Series instruments are not just temperature
indicators, they compute real-time results using
manifold pressure, RPM, fuel flow and temperatures.
G Series handles the raw data to eliminate confusion
and provide answers. It couldn’t be easier.
While constantly displaying critical information
during flight the G Series always work diligently
behind the scenes too, logging data to a handy SD
card for study later so nothing is missed.
It’s easy to go back in time, study trends and trace
problems to root cause.
Decades ago Insight introduced the first instrument
to display cylinder and exhaust gas temperature of
all cylinders simultaneously.
This innovation eventually became the industry
standard as all other manufacturers followed suit.
Engine monitors depend on numerous temperature
probes that have equal potential to inform or confuse
when any of them fail.
In fact probe failures can easily be confused with
Only the G series has a probe diagnostic
system built in.
injected you should take your plane up and try a 50
degree lean of peak to see how your injectors are
and here is how to do it with a G2, G3 or G4.
You will know the order of the lean, temperature
spread and fuel spread.
You should be under .5 gallons from first to last to
All of this will be on your G Series screen when
Order of lean is boxes appearing as they hit peak
Temperature distance from peak is the number in the
Fuel Spread is on the EGT columns after EGT peaking
Set Bar Height and Lean Threshold
First push of SEL knob you can adjust EGT bar height
on G2-G3-G4 Single and G4 Twin.
Turn SEL knob to adjust height (This should be
preset at Insight)
If you have to adjust the bar height every time you
have a bad probe (Check
Second push of SEL knob you can adjust the lean
threshold (rich or lean) on G2-G3-G4 Single and G4
Turn SEL knob to adjust threshold (Set to 50) Then
If one injector's fuel flow is higher and still
won't freeze on EGT bar after all the other have
this could mean a dirty injector.
The spray pattern at the nozzle is determined by
the hole shape, size, fuel pressure, and the
amount of ambient or deck pressure air mixed at
A good spray
pattern will provide maximum atomization and
smooth, consistent engine operation.
a nozzle with a dirty shroud or deteriorated
upper deck shroud seals will not provide the
same spray pattern as a clean unit.
the calibrated orifice has become damaged due to
rough handling or if the inside diameter of the
orifice has been scratched or chipped by
insertion of safety wire or some other equally
offensive material, the spray pattern will never
be right — despite the cleanliness of the screen
or the condition of the shroud seals.
are some Continental charts showing
injector fuel spread
A very crucial function is needed for
"Running Lean Of Peak" is Insight's exhaust
valve analysis in-flight.
on the ground after the damage is done"
EGT Variation Function is
a standard patented feature on all G3, G4
and G9 engine monitors.
This is a new form of engine analysis.
Some valve related engine faults produce a
slow periodic variation in EGT.
The oscillation rate is on the order of one
cycle every minute or two. This is just too
slow to be identified by occasional
observation of the temperatures alone. Yet
it is very important to discover this
phenomenon because it may lead to a
catastrophic engine failure. It readily
appears in a slow sampled spectrum analysis.
Temperature samples are collected once per
second for each cylinder and analyzed each
second. The entire sample interval is about
8 minutes. A normal indication will be a
flat line with a little noise, while a
trouble indication will show as an obvious
Use this page after you lean the aircraft - IMPORTANT
you see a recurring spike on one of the
cylinders you can turn the SEL knob to see
which cylinder it is.
You might want to pull that and a good
cylinder plug compare and bore scope
effected cylinder to see how the exhaust
valve looks and compare to good cylinder's
Here is a animated short to see the LOP
process of 50
As each cylinder hits peak the fuel flow
freezes on the EGT column.
On the animated image above cylinder 4 is
first to hit peak with a fuel flow of 15.5
On the animated image above cylinder 3 and 5
peaked with a fuel flow of 15.2 gallons
So 15.5 gallons minus 15.2 means the Gami
spread here is .3 gallons