I took a look at my exhaust on my 84 Bronco today and noticed i had 2 cat on it. do i need both of them or can i take the first (smaller) one out and still pass inspection? My 82 150 didn't have this. Whats the purpose of havin 2 cats?

 

Many people had no problem to pass emission with only one CAT, so you'll probably be OK, but I'd check older emission results to see how good they were. If they were borderline you probably need both CATs, but if you passed previous emission tests with flying colors, then you should be fine with one. BTW, leave the one CAT with the fresh air connector.

 

Front cat has a different chemical makeup than second cat - air tube between both makes them work as they were intended to clean up emissions at tailpipe.If I remember right front has rodium in it and second has platinum in it-unversal cats with air tube in middle have all the chemicals in one smaller unit(body)It would be impossible to pass an emission sniffer test with ONLY ONE of the factory design dual cat air tube design system.

 

i think im goin to take both the cats out and just use the one i gutted from my 150 and put it on. This cat doesn't have a fresh air connected but the engine in my 150 had a smog pump on it and was hooked up? do u really need the fresh air?

 

Why bother with putting any cats on it- the way you are going to do it isn't going to help with emissions anyways.

 

in my area u only have to have a visual cat they dont test what comes out of it just that it looks like u do

 

I know that in the state of Nevada they require the original smog equipment. I had an exhaust shop gut out my first cat and put a new Catco where the secaond was. Now when they look under my truck the have no idea the first one is hollow. I pass smog with flying colors. Keep in mind that the first cat is your y-pipe also. By removing it you would need to fab or buy a new one.

 

In Va. we are visual (state inspection)also unless in northern Va. where they state inspect AND emission test(sniffer)

 

rhissler,

If you are not going to run a working cat, then you will only need the air injection for the cylinder heads not for the cat. Without the air injection to the heads your O2 sensor will get "rich" readings and the computer will "lean" out your fuel mixture which leads to fouled plugs and performance problems.

 

hey Grey
Shouldn't the computer be in control of the air injection and adjust for when it is activated? If so then sending information indicating non active air injection may give DTC for non function, but CPU should make adjustment to mixture to compensate. Is air injection active all the time?
Now I'm gonna have to reveiw the function charts in my Ford Fuel Injection Book.
More Later.

 

Yes, the computer does control the flow of air injection through the diverter valve however, if it cannot correct the exhaust gas mixture by changing air injection flow through the diverter valve it will compensate by adjusting fuel/air mixture.

 

alright so right now my smog pump isn't hooked up because the guy i got the bronco from didn't have a belt on it but if i just hollow out the cats but leave them on, like im goin to do, this wouldn't effect my smog pump and my computer would it? and wheres the line for the cylinder injection? mine is carb so does this make any difference in what u said?