First, check the instructions on the MSD box and follow TS guide. Its very easy to follow. I had no spark and wet with gas plugs
BUT............The TS guided me to the point where the guide said the box was good, but I had bad coil. So I changed the coil with a brand new one. Still no fire: the Prob came to that it was the MSD distributor: Module went bad. And you wont see anything in the MSD guides, box or distro, that will tell you if the distro is bad, or how to TS if the MSD distro is bad
Bottom line, if ALL your wiring is kosher, if the box checks out good, the coil is good, and you are not getting fire, its the distro/ After doing a search, lotsa probs out there with the MSD distros