After trying numerous things like replacing the ingition module and the ingnition coil. Checking the fuses, replacing the plugs and checking the timing and timing belt, running the ingition diagnostic test. We checked the Diagnostic Trouble Code for a 91 Honda and came up with a code of 15 - Ingition Output signal. Can anyone tell me what this means and where do I go to find out how to fix it.

There is a strong possibility that installing a new Ignition Control Module (ICM)will solve the problem:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-4.html#post265896

Ensure all connections going to the ICM and coil are clean and tight.