[boomer]

Sorry to give you a non-answer but posting the actual codes along with the engine size might help others better understand the problem. When I read the phrase "catalytic converters missing" I am thinking there will be a big gap in the exhaust where the cat(s) used to be, and I doubt this will be the case as it would be easy to spot and the fix would be relatively obvious.

If the codes are for the catalytic converter being outside efficiency tolerance, I would think you have two main choices: -

• Replace the failing catalytic converter (clearly the right thing to do)
• Fool the emissions system by installing a spark plug non fouler on the secondary O2 sensor (may get you into trouble if discovered depending on local laws, environmentally inconsiderate, etc)

With the actual codes there might be other options / info.
Hope this helps

 

[boomer]

I would guess so, but have not tried it. The idea of the non foulers is to take the second (after the cat) sensor out of the exhaust stream. The first sensor is important for your fuel trims, the second is really only looking at the CAT efficiency as best as I understand it. Might be worth simply connecting an O2 sensor and see if that is enough to trick the system. There is probably also a way to simply feed the expected signal into the O2 connector, but that is beyond my capabilities.

 

[boomer]

Maybe something like this?
(108) How To Fix A Catalytic Converter Check Engine Code With Spark Plug Non Foulers! - YouTube