when does the split air pipe pump air?
 

when does the split air pipe send air to the cat? I'm just wondering cause I just removed my cats so now the air just comes out. I guess I'll be pulling the pump soon.

i would think the air pump sends air to the cats all the time. cause the air pump is always turning; and i dont know of any way it is turned on and off other than the car running or not.
well
later

The Air Control Valve (ACV) controls the airpump air and either dumps it or sends it to the split air pipe.

The ACV will send air either to the Cat ("split air") or directly to the exhaust ports, depending on the position of the switching valve (part of the ACV controlled by the ECU). This assumes that the Relief valve (ECU venting pump air to the atmosphere) is not energized (Also a part of the ACV).

Irv, Keith's dad.