I have a 1990 Civic. One day driving home from work it lost power at a stop light. Since then when I turn the key it doesn't turn over at all. It is getting fuel to the injectors. My ECU flashes once which indicates an oxegen content problem. I have disconnected the 02 sensor and checked the catalytic converter. There is a small amount of exhaust coming out, however it does not start to build up enough compression. Should I check the coil? Or which direction should I go in now? Any info would be helpful.

Perform tests, in Sections 1 and 2, below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563.html

I will try that and get back to you... thanks.