Gentlemen,
I own a stock 97 accord 2 door coupe, F22B engine, and had replaced the timing belt and H2O pump about 1 1/2 yrs. ago. Car has 188k miles, runs well, but was hearing noise determined by myself and a nephew that maybe the timing belt was slapping . Prior owner had a small area cut out or cover to see belt(exhaust side.) Noticed slack in belt, re- tensioned as per manual guidelines, had tension, started engine.......lost tension! What might be my next move???????

 

Are you fully torquing the tensioner all the way before starting the engine?

 

Should be able to loosen the accorn nut, rotate the engine forwards to remove slack, tighten acorn nut and the slack should be removed. But if the tensioner springs are missing/broke or the belt is incorrect for the application, you will need to remove the covers to inspect.
Incorrect belt tension/timing can lead to bend/broken valves.