LAUNCH KES-200 Starting System Analysis
E-10
ignition mode that means that one ignition coil is linked
to two spark plugs.
When testing the ignition waveform of 1 cylinder on
the first mode, select [1.DLI EFS] on the main menu,
and then make selections according to the cylinders.
For the second mode, select [2.DLI DFS].
Different method of cable connection should be
adopted for different ignition mode at ignition
waveform test. Please refer to the relevant
descriptions in this chapter for cable connections.
Selection of Primary/Secondary Waveform
DLI ignition mode can be used to test the primary or
secondary ignition waveform, depending on the
vehicle model. In general, the primary ignition
waveform can be measured as long as the negative
lead of the primary coil is found.
When the high-tension wire is hidden inside the
ignition coil, the secondary inductive device or
secondary signal cable should be used to measure
the secondary ignition waveform.
On the function menu of waveform display, press
[1.PRIM], a dialogue box for selecting waveform will
appear. Select the corresponding display mode, and
then the primary/secondary waveform will be
displayed.
Waveform Output
On the 2-cylinder ignition mode, KES-200 will display
two peak voltages. This is because the ignition coil is
connected to two spark plugs, one for positive
electricity and other for negative electricity.
For DLI of 4-cylinder engine, there are 2 ignition coils.
Each coil is connected to 2 spark plugs. When one of
them discharges positive electricity (Cylinder 1 for
example), it also discharges negative electricity to
Cylinder 4 at the same time. When another coil
discharges positive electricity to Cylinder 3, it also
discharges negative electricity to Cylinder 2.
Therefore, electric discharge is generated at cylinder 1
and cylinder 4 simultaneously. Same situation takes
place at cylinder 2 and cylinder 3. But this will not
cause burning in two cylinders at the same time. This
is because, while one cylinder is preparing for igniting
at the end of compression stroke, the other is in the
exhaust stroke. The mixture in three other cylinders is
not concentrated enough for burning.
As ignition takes place at two cylinders, the effective
discharge waveform, which causes burning, is called
the “effective waveform”. Another waveform that only
ignites without burning is called “ineffective waveform”.
The voltage of effective waveform is higher than that
of the ineffective waveform. In this way, the two
waveforms can be easily recognized.
Display Control
Select the discharge polarity via
[POSITIVE/NEGATIVE].
If the discharge polarity on the tested vehicle is
different to the selected discharge polarity on KES-200,
the waveform may be displayed inversely or not
displayed at all. To switch the polarity between positive
and negative, just press [7] key.
Print Output
The operation is the same as that for oscilloscope.
Please refer to the relevant section about
oscilloscope.
Help Information
User can press [HELP] key to view the help
information at any time while operating KES-200.
