Jeeper  Adventures Under the Hood  Jeeper

Pulse Air System

The Pulse Air System consists of two identical assemblies. Each has some tubing, a computer-controlled vacuum solenoid , a vacuum-operated air valve (pictured right), and a reed-type checkvalve (pictured below). Injecting air (oxygen) into the exhaust stream at the exhaust pipe or catalytic converter aids in the further oxidation of partially burned hydrocarbons. This system is used instead of the air pump found on many engines, and has the advantage of requiring a lot less plumbing.
Air Valve
There are two assemblies, one on each side of the engine. The one on the driver's side injects filtered air into the the catalytic converter (downstream), and the one on the passenger side injects air into the exhaust pipe just below the exhaust manifold (upstream).
Check Valves

- Details -

Here is one side of the Pulse Air System. It relies on pressure pulsations in the exhaust stream and a one-way checkvalve to draw air down from the air cleaner. When it feels like it, the computer actuates the vacuum solenoid which actuates the air valve, allowing air to flow from the filtered side of the air cleaner down through the reed-type checkvalve to the catalytic converter or exhaust pipe. The checkvalve should not allow exhaust to flow up the tube into the air cleaner, or bad things happen.
Pulse Air Animation

With the engine warm and idling, and with the lid off the air cleaner, it is easy to hear the Pulse Air tubes resonating when they are energized. Holding your hand over them you can feel the pulsing. However, the overall pressure is negative.

If you jam a vacuum gauge into the tubes inside the air cleaner, you should find that they will pull a little vacuum.

Not working?

If you are looking in the air cleaner, and the Pulse-Air tubes do not appear to be doing anything ever, it's possible that one or both tubes have rusted through somewhere. These tubes are supposed to resonate, like trombone or trumpet tubing. If there is a hole somewhere this will not happen.

Block the tailpipe with something while the engine is idling. If there is a hole in one of the metal Pulse-Air tubes, you will find it easily.

Note that a properly operating PulseAir system will not affect engine power output, the point being that removing it will not make the engine run any better, but will cause an increase in emissions.

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