As the subject says, when does the A.I.R. system actually send air into the manifold tubes and to the cat? I know this has been covered before but I just couldn't seem to find it in a search. If I remember correctly, doesn't it send air to the manifolds and the cat at different times? If this is true, I am more concerned with when air is pumped into the cat. If it's not true, then laugh at me and tell me what really happens. Thanks.

 

When engine is cold "OPEN LOOP," the port solenoid is energized and air pump pressure opens the passage to the exhaust ports.

During normal operation "CLOSED LOOP," the port solenoid is de-energized, the converter solenoid is energized, and air pump pressure opens the passage to the catalytic converter.

When the ECM determines that air divert is necessary, both solenoids are de-energized and air pump output is diverted to the air cleaner through a divert/relief valve. The divert/relief valve limits system pressure.
Air is diverted to the atmosphere under the following conditions:

• Rich operation.
• When the ECM recognizes a problem and sets the "Service Engine Soon Light.
• During deceleration
• During high rpm operation when air pressure is greater than the setting for the internal relief valve.

 

Thanks a lot. So essentially when the car is in closed loop during normal driving, air is always being sent to the cat except for during high RPMs?

 

during high rpms as well if the pressure is less the the relief valve setting.

 

thank you

 

you guys know how to test if the air divert valve is operating properly?