"F. George McDuffee" wrote in
message ...
On Thu, 05 Jun 2014 09:11:06 -0700, wrote:

two types of ignitions

Kettering, where the coil "fires" when the points open.
This is because the magnetic field in the coil collapses
faster than it builds giving a "hotter" spark.

CD [capacter discharge] where a capacter discharges a higher
surge of current/voltage with a faster rise time into the
coil and it fires as the magnetic field builds up. If you
have a "pointless" system, which is likely as you mention a
module rather than points, it may well be a CD. Is this a
computerized system where the advance is controlled by the
module, and the sensor or points are just index location
signals?


My truck's electronic ignition is somewhat like a motorcycle's, with
one coil firing two plugs on every crank revolution, one before
compression TDC and the other before exhaust TDC.
http://rockledge.home.comcast.net/~r...y/DIS_EDIS.htm
"The spark plug on the compression stroke uses the majority of the
coil's stored energy, while the other spark plug, on its exhaust
stroke, uses very little of that energy."

The ignition module acts like points and fires by interrupting the
coil current.
"When the switch opens, the power is interrupted and the primary field
collapses, inducing high voltage pulses into the secondary coil
windings."

-jsw