X-431 Throttle User Manual
106
13.3 Secondary-direct ignition analysis
Connection
：
1) When the high-voltage wire is exposed, plug the BNC end of secondary
ignition pickup into CH1/CH2/CH3/CH4 channel of Scopebox, then connect
the high-voltage clip to high-voltage line, and crocodile clips to ground.
2) If no high-voltage wire exposes, dismantle ignition coil of tested cylinder and
use direct ignition extension cord. Connect one end to ignition coil which
should be grounded via direct ignition grounding wire, and insert the other
end into cylinder to joint with spark plug. Then plug the BNC end of
secondary ignition pickup into CH1/CH2/CH3/CH4 channel of Scopebox,
then connect the high-voltage clip to high-voltage line, and crocodile clips to
ground.
Connections are shown in Fig. 13-4:
Fig. 13-4
Fig. 13-5 shows the normal secondary (the upper one) and (the lower one)
primary ignition waveform of direct ignition system. Beause the on/off of primary
circuit is not opening/closing of mechanical contact, but the conduction of
transistor. The primary voltage has no obvious oscillations within the duration,
but the voltage increases during the magnetization process due to current
limiting, and this change can cause corresponding fluctuations of secondary
voltage line as a result of induction of ignition coil.
