Direct Ignition System (Dis)
The crankshaft position sensor senses slots (4 per cylinder, 20 degrees apart) around an extension of the drive plate. Basic timing is preset by crankshaft sensor position and is not adjustable. By using a crankshaft sensor, spark scatter has been eliminated.
A cam sensor is located on timing chain cover. Cam sensor senses slots on cam timing gear. Fuel injection synchronization and cylinder identification are provided through cam sensor. A unique combination of slots on cam gear are used to identify cylinders and initiate fuel and spark for start and run conditions.
The SBEC fires one coil at a time. This one coil in turn fires 2 spark plugs at once. One cylinder is on compression stroke and the other cylinder is on exhaust stroke. A low primary resistance allows SBEC to fully charge ignition coils for each firing. See Fig 1.