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.