Testing the ignition control module is a little trickier. When the module is exposed to a specific heat range—which can vary—it tends to fail. Therefore, the test may not be accurate.

CD ignition use a separate coil and ignition box along with the distributor, and the system makes it easy to fire a really hot spark all the way through the rpm range.

Classic Delco distributors seem to cover the gamut of types, ranging from single-point to dual-point in aluminum and cast iron. We're about to tackle a cast-iron, tach-drive distributor.

The first step in replacing ignition coils is determining the type., Depositphotos Here’s How To Diagnose and Test An Ignition Coil Let’s do this!

The distributor houses a movable breaker plate that can advance the ignition via a set of centrifugal weights or with a vacuum canister diaphragm system.