SirKnightTG

I hope my high flows that came with my Kooks LT package last longer than that. lol.

I put 1K miles in less than a month.

I looked in the cats but I don't know what material that is. I only know I can blow through them with my mouth just as easily as a straight pipe. LOL.

MustangGT0405

So how did you know they were gone? I have had them on my car for about 2 months.

If mine went out I would just cut them out and weld in straight pipes.

Norm Peterson

OBD II monitors converter efficiency, so unless the downstream O2 sensor signal was tinkered with I'm betting it threw a code with a number somewhere between P0420 and P0439.

Replacing a converter with straight pipe gets you into trouble in some areas either at periodic emissions inspection or at roadside inspections. I know that NJ at least used to do the roadside thing.


First guesses as to why they died is either running too rich or there was excessively high exhaust gas temperatures and it burned up. If that's the case, whatever it is needs to be fixed or the same thing will happen to the new cats.

Norm

MustangGT0405

Thanks Norm, I am a little less worried now. My A/F doesnt ever go below 11.0 and I have not heard or felt anything odd lately. I dont have my rear O2's on though so I would not get a code.

What would the symptoms of a blown cat be, without the comp?

This and a few other things I have read lately has me a little spooked running an aftermarket ceramic cat.

I am now on the fence whether to just order a MAC O/R Prochamber and be done with it.

No emmissions or inspections in FL. Although when I used to live up north we used to weld in hollowed out sleeved cats so it looked like you were still running them. When the added the sniffer that was no longer an option. That is why everyone should keep their stock H pipe, just in case.

Norm Peterson

I suppose that either excessive backpressure or loose stuff rattling around inside could happen, though backpressure might cause a separate code.

If your upstream O2 sensor goes bad, it'll probably run slightly rich all the time, and that could kill a cat. Suddenly poorer fuel mileage would be a clue. I think that's what happened on another car of mine with a retrofit multiport EFI system, actually.

Maybe shane will drop back in and mention what caught the problem for him.


Norm

shane.stockard

It was the after cat O2 sensor that was throwing my engine light. The pypes cat had the O2 sensor in the cat its self. So I had the sensors moved behind the cats. I have now thrown a engine light for awhile now. But I really did not have the time to have the exhaust looked at since I was in the process of moving.