Your 1990 Honda Accord overheating during the smog test would more than likely not have caused the smog check failure you've indicated. CO emission value of 8.73 is extremely high. This represents a condition called "running rich". Your Honda Accord's air/fuel ratio is not near specifications. 14.7/1 is (14.7 parts air and 1 part fuel) is what is needed for optimum fuel combustion. In this case it appears that your Honda Accord is delivering more fuel than the combustion chamber can burn, resulting in high CO emissions; as well as leaving behind un-burned fuel in the form of HC.
We recommend having a smog check repair station inspect possible rich fuel faults. They should begin with looking at mechanical faults such as leaking fuel injectors, defective (saturated) EVAP system, disconnected, broken, leaking vacuum hoses, and the like... any mechanical problem which would cause more fuel the necessary to get into the engine.
Once mechanical faults are ruled out, the diagnosis should turn to your Honda Accord emission control system (the electronics). This includes inspecting all emission sensors, specifically the MAP (manifold absolute pressure) sensor. Your Honda Accord's MAP sensor send crucial engine air intake, pressure, and vacuum information to the engine control unit (ECU). Based on the MAP's voltage signal the ECU decides how much fuel to mix with intake air. Without a properly functioning MAP signal the ECU could be dumping heavy amounts of fuel. Mind you, in order for the MAP to be working properly, the engine can not have any vacuum leaks. All vacuum hoses need to be inspected. This inspection should occur as part of the mechanic diagnosis portion of the overall smog check failure diagnosis.
