Scope and Multimeter Operations Ignition Scope
140
To open the Digital kV View, select Setup from the upper toolbar, then from the
menu select View > Display > Show Digital kV. (Figure 9-73).
Figure 9-73
This feature displays the digital kV readings corresponding to the selected channel,
and provides another way to monitor the secondary ignition system. When testing
wasted spark ignition systems, power firings display on channel one and waste
firings display on channel two.
The digital values are only as good as the source signal. If there is a problem
with the connections or setup and a stable waveform is not displayed, the
digital value may not be calculated correctly. If problems are experienced with
the digital values, check lead connections and setup settings. If a
measurement cannot be calculated, dashes display in place of values.
Firing kV, Spark kV, and Spark Duration (burn) measurements are calculated from
the secondary waveform.
• Firing kV (FKV)—voltage required to overcome the rotor and spark plug gaps
and establish a spark across the spark plug electrodes.
• Spark kV (SKV)—voltage required to maintain a spark across the spark plug
electrodes
• Spark Duration (Burn)—time the spark is maintained across the spark plug
electrodes.
Min/Max and current values for Firing kV, Spark kV, and Spark Duration are
displayed as digital values for each cylinder in the firing order. Intermittent problems
that happen too fast to be seen on the live waveform (without pausing / reviewing)
will be captured in the Min/Max reading, making it possible to spot problems that
can be difficult to see in the live waveform.
Digital kV / Multiple Spark Ignition Systems
On vehicles with multiple spark ignition systems, when more than one spark per
cylinder is present, Firing kV (FKV) is calculated at the start of the first spark and
Spark kV (SKV) and Burn are calculated from the last spark.
To calculate the Digital kV and Burn measurements, select an ignition pattern with
a 10 ms sweep, such as Parade 10 ms or Cyl 10 ms when testing a multiple spark
system.
Digital kV cannot be correctly calculated if, in the Ignition Scope view, the end
of the last spark for each cylinder is near the end of the screen or off of the
screen.
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