learn me on cat-converters and O2's

[original balzer]

So I searched and didnt find the answers I need.

My 97 has rotten exhaust it was true dual 2.25" with 2 cats and 4 O2's and 18" long glasspacks. Its swiss cheese now and the "doughnuts" are shot. It sounds like CHIT. It also throws a code for bad cats.

If I can I would rather not run a cat on it as they are not required here and they add to the expence. Its an old truck with alot of miles so I dont want to spend a bunch on exhaust.

Heres the options (or at least what I think are options)

I have herd they sell a "spark plug anti-fouling bung" sounds like its basicaly a sleeve with a small hole in the end. they claim you use that on your rear O2's and it fools them into thinking there is a cat there. If I can go that route Ill do true dual without cats.

If not and I have to buy a cat I only want to run single cuz Im definatly not gunna buy 2 cats. BUT what do I do with the other 2 O2's?

And finaly has anyone run a high flow cat are they any good and about how much are they? I was told to expect $430-450 for a stock cat. OUCH thats the price of the rest of the exhaust.

 

[lectric80]

What year truck are we talking about here? If it is a 97, that would be a problem. Any vehicle made 1990 and newer, you cannot remove the cat. Prior to 90 you could remove it and say that it wasn't there when you bought it, and they would not make you replace it. The fine on a 90 and newer, if you are caught, is about 10K. I would think that the cat wouldn't be that expensive. I did a quick search (and granted I am guessing here) but most 97 catalytic converters can be picked up for around 60 -80 dollars each.

 

[original balzer]

I havent looked into it yet I guess I need to go get an estimate so I know better.

 

[loafer]

You should keep the two "upstream" O2 sensors before the cat. The ECU needs these to run in closed loop.

You are right about the O2 sensor downstream from the cat though, you can buy a little device that replaces the sensor and "fools" the ECU into thinking there is a well performing cat there. Jegs and Summit used to sell them.

The only advantage to removing the cat is $$$. It won't hurt performance on most engines.

 

[Blue85]

The first two O2's are totally required. The second two are just to monitor function of the cats. With leaks in the system you should expect to get codes for O2 and or cat performance. The cats might be just fine.

If you do want to replace the cats, universal ones are generally cheaper (check eBay, Summit, etc. for units <$50) and since you have two, they don't have to be "high flow". In fact, the price of these is not a lot higher than the cost of O2 simulators (http://www.o2simulator.com/)

BTW, check engine lights are not there to tell you about how the engine is running. They come on when a problem with emissions is suspected.

 

[dyeager535]

Should be able to install basically dummy O2's in place of the rear ones after cat removal. You'd have to if you remove the converters.

Really not that much anymore for good flowing replacements, and if your cats are still good, no reason not to have them put back in IMO.

 

[BGKYK5]

If the price is even close, I would recomend getting new cats as opposed to downstream O2 slimulators. Cats on a '97 won't hurt performance and when working right they remove something like 95% of the HC, CO, and NOX emissions. That way you avoid any leagal entanglements and aren't so hard on the air. I don't know where Roosevelt is, but somedays the air in the Salt Lake valley can be kinda nasty.