Many of the maintenance and testing methods discussed for an air injection system apply to the pulse air system. Inspect all hoses and lines. Measure O2 with a four-gas analyser to test the system. Exhaust analyser oxygen readings should drop when the pulse air system is disabled. If readings do not drop, check the action of the aspirator (Reed) valves.
Fig. 32-10 shows a mechanic testing the operation of the aspirator valves. With ~he engine running, you should be able to feel vacuum pulses on your fingers. However, you should NOT feel exhaust pressure pulses trying to blow back through the valves. Replace the valves if they do not function as designed.