How does the computer know which trailing ignition coil to trigger? Does the crank angle sensor send some sort of special signal for one coil vs. the other? Is there some other sensor that tells the computer which to fire?

 

http://www.teamfc3s.org/info/articles/demystifying.html

 

Its all in the CAS. It gives a signal to the ECU.

 

Thanks, Hailers -- excellent explanation on the site.