2.3 dohc wont pass smog - 1993 Honda Prelude

Did you do a full tune up?
Do a compression test and check for any cyclinder that is low in PSI.
Look of wet plug and oil coated plug(s).
== Which item CO,NOx,Hc is failing?
You may need to repose to add information.
Use a plug non-fouler / protector on the weak cylinder will help if HC is just shy from the passing limit.