[RockBit]

Originally Posted by patrickt

The capacitor is installed "across" the positive and negative feeds to the MSD box. If it was just a wire it would be "short-circuiting" the two wires. But, it's a capacitor, so once it reaches its fully charged state it stops the direct current going across it but continues to act as a "shock absorber" for direct current voltage spikes, thus protecting the MSD box from them. Plus, if your alternator is leaking AC current out, a capacitor across the lines acts as a short cut for the AC to pass right through and head back home without ever going in to the MSD box to help muck up the electronics.

Great explanation. Thanks. I’ll put one on mine.