missing the o2 generally makes the car run directly off the maps on a honda. the maps usually are set up as a 13.5:1-13:1 afr. since it's obd1 there is only a primary o2 and the o2's responsibility is to give feedback to the ecu and adjust fueling to get it to 14.7:1 when it is in closed loop operation (less than 75% throttle position w/ o2 active in place). that's why you'll see an air fuel meter bouncing around so much because that is the o2 and ecu correcting from the fuel tables.

obd1 emissions test is on a roller at idle and then at a load at a specific rpm. typically it's going to test closed loop since at cruising you're not above 75% throttle position. the gases it's looking for at 14.7:1 and running through a cat will be way different than your car at 13.5:1 running through a cat.