A good location for one of the coil packs is on top of the engine behind the fuel manifold provided by SDS. Installation ion this location will require removal of the engine lifting loop typically mounted at the rear of the engine of the case split.
Be sure to inform SDS of your plan to mount a coil pack in this location as they will; need to adjust the coil pack wiring harness.
Wiring Harness From ECU
The coil pack harnesses have two connectors. One of these connects to the large black connector shown on the left side of the coil pack shown in the picture to the right. The other connects to the other side of the coil pack.
The large black connector has 4 wires, two red, one black and one white. The first red wire is a power wire, the remaining red, black and white control the coil pack firing order.
As they control the firing order or the coils in the coil pack, the order of these wires in the black connector is important . You will notice that each coil pack has three individual coils with an electrode on either side of the coil. One coil is connected to spark plugs on cylinders 1 & 2, another to cylinders 3 & 4, and the third to cylinders 5 & 6. You will find the cylinder numbers are stamped on the engine case near each cylinder.
The spark for cylinders 1 & 2 is controlled by a red wire, 3 & 4 the black wire and 5 & 6 by the white wire. For a coil pack mounted on the rear top of the engine, it makes sense that cylinders 1 & 2 be controlled by the front coil, 3 & 4 by the middle and 5 & 6 the rear coil. This eliminates ignition wires crossing over each other.
To achieve this firing order, the wires on the black connector are installed in the order red, black and white. If for example, the wire order on the black connector was red, white and black then the front coil would control cylinders 1&2, the middle 5&6 and the rear 3&4. Therefore it is important that the ignition leads from coils are connected to the correct cylinders.
You may have noticed that the spark plugs on each cylinder pair fire at the same time as they are both controlled by the same coil. However, at any one time only one cylinder of the pair will have a fuel/air mixture to ignite. The spark to the other cylinder is “wasted” which gives rise to the term “wasted spark”.