Emission Test With Hi-Flow Cat and No Air Pump
Failed due to high HC (hydrocarbon)
The 3rd Gen RX-7 comes with a three-way catalytic converter that's divided into three chambers. The front chamber handles nitrous oxides (NOx). The air pump supplies air to the center chamber (and to the exhaust stream before the down-pipe). This injected air is used by the rear chamber of the converter which handles hydrocarbon (HC) and carbon monoxide (CO), so it's not surprising this car, using a hi-flow, three-way main cat without an air pump, failed with high HC.
It may be possible to use a programmable fuel computer to lean out the mixture and reduce the HC output, but it would be difficult to reduce it from 1.10 g/mi to the 0.49 g/mi reference. It looks like an air pump is necessary to pass this state's emission test.
Tips for Passing an Emission Test
Make sure your car is completely warmed up before it's tested for emissions. It's also important to keep the car out of the boost during a dynamometer type emission test. Since a technician will be "driving" the car, be sure to tell him to be very gentle with the throttle. You should also pinch off the hose that runs from the small, black fuel catch tank (under the intake elbow) to the extension manifold. This keeps the car from purging the fuel in the catch tank into the manifold during the test which will give you a very high HC spike.
Test car in red, reference car in black, speed in green