In closed loop, my AIR diversion valve never diverts to atmosphere, constantly sending air to the converter (causing my previous converter to burn up after only one year). Since a new valve costs over $400, I grabbed one from the junkyard, which behaves exactly the same. In both cases, the valve is unable to switch between the converter and atmosphere.

I'm looking for a way to evaluate whether or not a valve is functional without having it connected to an operating AIR pump. This way I can go back to the junkyard to buy a working unit.

By removing the two solenoids from the valve, two small vacuum connections are revealed. The connection that switches between exhaust and converter/atmosphere holds a vacuum, while the connection that switches between converter and atmosphere does not hold a vacuum.

Should both connections (behind the solenoids) hold a vacuum?
Is it common for the converter/atmosphere section of the valve to get stuck in converter mode?

Any insight into how the diaphrams and individual valves within the diverter valve work could be helpful.

 

Why not remove the AIR system

 

Your computer tells the diverter valve when to exaust. I would look to see that all your sensors are functioning. Odds of two valves doing the same thing are slim I think. My z28 is an 85 and it reads the vacuum differential sensor to determine what to do with the diverter valve.