Engine Misfire - The Saga continues

[Bobcat]

Byron ... you should be more concerned with voltage spikes than current , as voltage fluctuations/transients are what kill the MSD system ... and other electronics . This normally happens , for example , if you jump start your car ( connecting/disconnecting the jumper cables ) or switching some accessories on and off . This causes your voltage to do weird things ( transient spikes ) that can hurt the MSD . For lack of a better description , this is a noise filter ( surge suppressor/clipper ) and it must be located such that it filters the power going to the MSD system .
You could probably get one at the local Radio Shack ( around 25 k to 50 k microferrads and 16 vdc ) , but in all honesty , the MSD unit is such a neat package and comes with instructions and mounting hardware , it`s hard to beat .

[Ronbo]

Actually the best filter would be a combination of a choke (coil) in series and a capacitor in paralell. Chokes work much better at blocking the pulses than caps do.

If you have a 2-way radio shop near you stop by and see if they have any of the Motorola filter kits. The car battery is basically like a huge capacitor and provides most filtering in your electrical system but high frequency spikes can still ride on the system. The choke filters by magnetic fields as opposed to static fields like caps.

The secondary (low voltage) winding on a power transformer will also work.