Catalytic Converter Question

[Old77]

Good thread.

Yeah, turned out to yield some good info in the end

 

[tuberbob]

I am going to get some pics of my truck, because in the thread I started, the info I learned leads me to believe that what I believed was a modified vehicle may in fact be completely stock. I will do my best to photograph the entire emissions/exhaust system, because I am burning with curiosity to know what I have here. If it helps, I can also post the VIN.

I will return shortly with pics.

 

[CorvairGeek]

I wonder if because of the A.I.R systems on our trucks that connect to the manifolds is what feeds the extra 02 to the three way cats rather than a tube run down to the cat itself????

Genrally, the air injected at the manifolds is for open loop operation only (at least the ports upstream from the O2 sensor), primarily for the control of HC and CO after start up. The converter only gets air injection (if so equipped) when the engine is warm. During deceleration, a hot idle, or under an overheat condition (or close to one), the system will divert to the air cleaner to prevent exhaust back fires or overheat of the catalytic converter.

As vehicles got more sophisticated, i.e. fuel injection, the need for extra air to the converter does go away. I sometimes forget that there are Squarebodies after '87 that are more advanced. Mine is so much like an antique from the 60s.

 

[tuberbob]

Posted in my thread as well, but for anyone interested, here are pics of my emissions/exhaust system. Everything appears to be stock to my untrained eye.