Clogged Catalytic Converter?

[rgeier11]

I have suspected the catalytic converter on my 209k mile Galant has finally taken a dump. I'd like to get some insight before I sawzall it off and replace it with a straight pipe. The factory exhaust is completely rusted at the flanges, hence the sawzall.

THE SYMPTOMS:
When I first start up and drive the car it runs great with minimal hesitation during spool up. After driving the car for 15mins or so it will stumble/stay flat/no power. Sometimes while hesitating the car will blast off and accelerate hard.

If I stop the car and let it cool for a little bit and hop back in, it will run great.

 

[iceman69510]

I would think it would stay clogged all the time, no?

BTW, to remove it, I would just cut the nuts off. The one end is held with bolts, so you can knock those out if you cut the nuts off. theother end has studs in the cat side, so if you cut off the nuts you can get it out as well, leaving holes in the pipes at both ends to reattach a test pipe with bolts.

 

[Yao]

I have melted cat before, and it is power loss all the time.

 

Quoting iceman69510:
I would think it would stay clogged all the time, no?




SOmetimes it can be a molten chunk in there that can clog and unclog depending on how it rolls around in there. On my Montero I had a piece the size of a tennis ball that looked like igneous rock that rolled around.

 

[Diego]

May be way off hand here, but...... check your ecu and have a look around in there.


If the cat failed it would be like said above, it would stay suck at all times, you resting the car doesn't let heat off the cat and let it expand outward then cave again.


Hell, you should out the stock and get a decent 2.5"~3.0" turbo back if you plan on going straight pipe.


I like no cat straight turbo back. Imho my car sounds very serious when at idle and isn't too loud, it is a 2.5"dp to 3" Certified 0erformance Muffler /ubbthreads/images/graemlins/hsugh.gif