Supra L6-2997cc 3.0L DOHC MFI (1998)
Igniter: Description and Operation
CIRCUIT DESCRIPTION
A DIS (Direct Ignition System) has been adopted. The DIS improves the ignition timing accuracy, reduces high-voltage loss, and enhances the
overall reliability of the ignition system by eliminating the distributor. The DIS is a 2-cylinder simultaneous ignition system which ignites 2
cylinders simultaneously with 1 ignition coil. In the 2-cylinder simultaneous ignition system, each of the 2 spark plugs is connected to the end of
the secondary winding. High voltage generated in the secondary winding is applied directly to the spark plugs. The sparks of the 2 spark plugs pass
simultaneously from the center electrode to the ground electrode. The ECM determines ignition timing end outputs the ignition signals (IGT) for
each cylinder. Based on IGT signals, the igniter controls the primary ignition signals (IGO) for all ignition coils. At the same time, the igniter also
sends an ignition confirmation signal (IGF) as a fail-safe measure to the ECM.
