Originally posted by SEBilly:
"Some of the multi-coil ignitions are a waste-spark type, and fire on the exhaust stroke as well. This means the plugs fire twice as much. To make things worse, the second spark goes in the opposite direction, so they get hammered from both sides. That's why some of them are dual platinum."

Comments?
Thanks
Bill



This is exactly our system. The circuit of the electric is like this:

Coil+ --> wire --> Center Electrode Plug1 ---. Ground Electrode Plug1 --> Engine Block --> Ground Electrode Plug2 --> Center Electrode Plug2 --> Coil-

So each timne the coil fires, 2 plugs spark. The reason this is done is not for emissions as there is not enough air in the exhaust for the second spark to do anything. It is done because it is easier for the computer to control 3 coils then 6 coils and it is cheaper. Cheaper is the key word.

The Zetec 4cyl uses this method also. But only 2 coils.

V8 uses 2 four cylinder coils.


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