The air injector pump with an integral filter compresses the air going to the manifolds by injection tubes into the exhaust system in the area of the exhaust valves. This fresh air burns the unburnt portion of the exhaust gases in the system thus reducing exhaust contamination. The diverter valve when triggered by a sharp increase in manifold vacuum stops the air from getting to the exhaust port areas thus preventing backfiring during this richer period. The diverter also includes a relief valve that could by-pass the air out of the pump if the air pump clutch fails to disconnect the pump at high speeds. The air pump was standard equipment for USA Daytonas.