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LAUNCH X-431 PAD III User Manual
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13 Automotive Ignition waveform (Toolbox)
The ignition system is the system which has greatest impact on the
performances of gasoline engine, as the statistical data shows that nearly half of
the failures are caused by poor work of electrical system. And the performance
tests of engine often start from the ignition system. Nowadays ignition system
includes distributor and distributorless. Distributorless includes independent
ignition and simultaneous ignition.
1. Distributor ignition system i.e. contact breaker with contact-controlled ignition
system (commonly known as the platinum) and contact breaker with
noncontact-controlled ignition system combined with magnet, hall
components or infrared.
2. Independent ignition system: crankshaft sensor send out the ignition timing
signal and cylinder identification signal so that the ignition system can send
out ignition signal to specified cylinder in specified time, each cylinder has its
independent ignition coil.
3. Simultaneous ignition system: two cylinders share one ignition coil, when two
cylinder pistons reach top dead center at the same time (one is compression,
another is the exhaust), two spark plugs will be ignited at the same time, at
this time, the ignition for the former cylinder is in high-pressure low
temperature gas mixture, the ignition is valid, while for the latter one is in
low-pressure high temperature exhaust gas, the ignition is invalid.
X-431 PAD III can test and analyze the secondary signal for various engine
ignition systems.
13.1 Secondary-distributor ignition analysis
The following connection should be made before performing it:
1. Power the Scopebox on: Power is provided to the Scopebox in either of the
following ways:
• Power adaptor : Insert one end of the power adaptor into the Power
interface of the Scopebox, and the other end to the AC outlet.
• Battery clamps cable : Plug one end of the power adaptor into the Power
interface of the Scopebox, and then clamp the other two terminals to the
vehicle's battery (Red to +, and Black to -) respectively.