The ECU is based on the Arduino micro-controller. They control both the injectors and the spark and require feedback from the motor timing.
It requires either a sensor on a crank sprocket with one missing tooth or a once around signal on the camshaft to know when top dead center of cylinder 1 occurs.
Last time I looked inside the crankshaft cover it seemed pretty crowded. I don't think there is room for another sensor in there.
Perhaps a magnet mounted on one of the cam sprockets would suffice. More study is required.
![Huh? ???](http://zggtr.org/Smileys/default/huh.gif)
From their documentation ...
" A dual wheel trigger is one where there is a primary multi-tooth wheel combined with a secondary single pulse to provide location information. The primary input should contain no missing teeth. Both pulses can run at either cam or crank speed, but sequential operations requires that the secondary pulse is located on the cam. The design of the secondary trigger can vary (Eg a single short tooth, half-moon wheel etc), provided it only provides a single pulse per revolution.
Tooth #1 is defined to be the first tooth on the primary wheel AFTER the pulse on the secondary wheel."
it looks like the missing tooth is not necessary if there is a second sensor to indicate where the cam is. So a sensor on the flywheel and another on the cam should be what they are looking for.