GxT V055-01 Diagnostic Analyzer - Manual (Page 11)

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The EngineLink will advise that the throttle should be
opened abruptly. This sets the minimum and maximum
readings. The composite screen will appear, showing
the average readings for all coils.
SPARK BURN DURATION
The spark burn duration on a DIS is usually between 0.5
and 1.5 mSec. Long burn duration comes from narrow
or fouled plug gaps, insulation shorts, low cylinder
compression, and rich fuel mixtures. Short burn duration
is caused by breaks in ignition secondary wires, wide
spark plug gaps, worn plugs, high circuit resistance, and
very lean fuel mixtures.
A reduction in burn durations, with snap acceleration, is
an ideal check for spark plug gaps that have the sharp
edges worn off, and to see that insulation does not arc
through.
Problems like wire breaks and high secondary resistance
are most easily detected at a moderate and steady RPM
between 1000 and 2000.
FIRING KV — Live and Maximum
Firing KV is the voltage that is required to start ionizing
the air/fuel mix in the spark plug gap. For the ignition
to always work, the KV available from the coil must be
more than the highest KV requirement. Causes of high
KV can be a wide or worn plug gap, a broken sparkwire
conductor, or a lean fuel mixture. Unusually low KV can be from a fouled plug gap, secondary insulation
failure, or low compression. Typical live KV is 5 to 10 at a steady RPM with not more than a 5 KV difference
between the highest and lowest.
INDIVIDUAL CYLINDER READINGS
Use the up and down arrows to see four additional screens that show data for the individual cylinders.
The burn time bar graph screen shows live spark burn time for each cylinder. The number in the upper left
corner shows the average for all cylinders. Press HELP to see this and explanation of the screen. The burn
time numerical screen shows min., max., and live spark burn time for each cylinder in numerical format.
The KV bar graph screen shows live KiloVolt readings for each cylinder. The bottom of the left bar
represents the minimum kilovolts and the top is the maximum. The top of the middle bar shows the live
reading for firing KV.
The KV numerical screen shows live, maximum and exhaust KV per cylinder in numerical format:
Ignition Secondary - Distributor