The AIR system is injecting air (oxygen) into the exhaust manifold before the O2 sensor. Wouldn't the O2 readings change if the A.I.R. was removed because there wouldn't be extra air coming in? Or am I missing something here?

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Good question. I never thought of that. But that would seem to make sense. The AIR tubes are shooting air into the ex. manifold before the O2 sensor sees the exhaust.

If the computer is programmed from GM to take the AIR into account from the O2 reading, then it would seem that it would lean out the mixture quite a bit after you took out the AIR system. After all, it would think that it's running REALLY rich due to the lack of oxygen.

Anybody have any experience with this problem, or have we just thought up a "doesn't matter" situation?

AJ

 

Yea you would think so but nothing happens.
BBT, im curious what the real deal is.

SSC

 

The real deal on the AIR is that air is injected into the exhaust manifold or headers while the engine is still cold. At a certain coolant temperature (can't remember) the divert valve then swaps over to inject the air into the catalitic converter. The air is then no longer injected into the exhaust stream before the O2 sensor.
This is done to help burn the exhaust gas at the exhaust ports while the engine is still cold, and allows the cat to heat up before air is injected into it to let the cat do the burning of the "unburned hydrocarbons".
The O2 sensor during this warm up time will be in "open loop" so the computer does not really register a lean exhaust condition.

 

Ozzy is right, no air to the manifolds in closed loop.

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sweet, I learned something today. I always wondered why the hell that box was there. Well used to wonder until I took the whole system off.

 

Those guys are correct. That is the purpose of the "diverter valve". During Open Loop operation (O2 sensor ignored) the air is injected into the manifolds. Once Closed Loop operation is acheived, the diverter valve sends the air to the catalyst.

ON a side note, a failed diverter valve can set a code 44 (Lean Exhaust) because it can put air into the manifolds during closed loop operation.

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Cool. So what you are saying is that if I were to remove my AIR tubes going to the ex. manifolds, then my car would be polluting the atmosphere at start up, but once it reaches closed loop (and if I left it hooked up to the cat) then it would still pass emissions?
That's all I really want. Just to get rid of those damn tubes under the hood. I still want the cat to work correctly.

How can I leave the cat hooked up and still have the AIR running into it? Just bypass (and remove) the diverter and have the pump running to the cat at all times? Or would I have to leave the diverter in there and just plug the side that goes to the "used to be there" tubes?

AJ