Catalytic Converter Rattles With Engine Running

I've been hearing rattling under the ZJ ('93) for a while now but its worsed recently an rattles louder. Jumped under with the engine and followed the sound to the catalytic converter, more towards the front it to be exact.

Is it clogged or failing or bad ?

 

Can i replace it with flex pipe ? I most definitely cant afford another cat right now.

 

So are you saying that there is something loose inside of it?

 

Yes. Googling and reviews say it's failing because the honeycombs are breaking and the pieces are jumping around...or the heat shield is rattling but I would visually see it shaking if that was the case but the rattling comes from the converter towards the front of it.

I had a '95 Jimmy 4x4 a couple years back. Hacked the clogged converter off and clamped flex pipe from O'Reillys for $12-15. Eventually it rusted, but the tranny blew up and died before I could drive it any further.

 

Sometimes the heat shield around the cat tends to rattle. Some sections rust and fall off while others hang around for a while rattling away. I've had some success with a stainless steel band clamp for several years.

 

I'll remove the heat shield and see, but the rattling comes from inside of the front of the cat

 

Mine does to. I will get around to doing something with it eventually. My XJ runs real good but sounds like a rattletrap, really makes it sound worse than it is.

 

As of yesterday I see a decrease in my acceleration, before I could floor it on the freeway and easy jump to 80-100 mph but now when I floor it it struggles to get to 80. Before I could feel good shifts almost on point, now shifting hesitates...and I'm thinking the cause is lack of engine power, which is caused by the clogged/bad converter. The new spark plugs I just put in a month ago seem already burnt.

 

If you don't have emissions testing you could cut it off and hollow it out and then reinstall.

 

I'll have to Google it but I don't think we do, I drove without my cat for awhile through city and highway with that Jimmy... Loud lol

 

Shaking my head-

You THINK there is a cat issue, use a exhaust back pressure tester. A loaner or rental.
You mention no money for a replacement - BUT did I just see a post referencing an NEW RADIO?
This is @18year old SUV and you mention 100mph as normal - AND it has known issues.

GMAFB speechless.

FYI: It is illegal to remove or render inop a emission device - thats FEDERAL not a state reg.

 

Radio was given to me and the rest I had from my last vehicle. 100 isn't normal, I do that to see if it's capable of doing as it says on the dash and if I get there and to complete stop with no problems and take off normally with no problems then I assume things are working as they should...lol no not normally. And ok on the exhaust back pressure tester. Yea, I didn't have money for a $300-500 cat replacement so I just cut it out and replaced it with flex pipe and clamps...right or wrong I was living in rough times and something had to give, regardless of any laws.

 

For a rig with various motor, trans, drive shaft, end links, exhaust, electric issues ETC...shaking her down at 100 could be an enlightening trip.

 

I installed a pressure/vacuum gauge to the port for the O2 sensor on the exhaust. From what I have read, there should be no more than 3 p.s.i. on the gauge. I did it on a cold engine so no codes would come up.

 

It was actually a smooth shot, on the freeway I usually drive 70-80 mph normally. When I bought this Jeep from my uncle I told him the cat seemed failing or bad. He told me to drill 2 holes in the front of it...I didn't

 

Bought some new NGK V Power plugs to keep track of timing them after some time.

 

I'm sorry. Don't mean to knock your spark plug purchase. Ummmm....But I tried them years ago in my motorcycle, a Yamaha Virago, and my XJ. I found they did not produce any more power or gas mileage improvement. And in fact burned the piston heads in the bike. Stick with what the manufacture recommends. If they found a better spark plug. With the pressure the govt is putting on car manufacturers to get better gas mileage. They'd be using them.
And your spark plugs have nothing to do with your timing. Unless you manually advance or retard it.

Sorry....just my 2 cents. And my experience.

 

Its cool. What brings timing to the probability in this ?

 

It doesn't dude. If it was the timing. Your motor would be bucking like a rabbid bull. It just wouldn't sound or run right. Misfiring. It would be very noticeable. No git up and go from a stop light. Your gas needle would just drop like you have a leak in the gas tank.

 

Oh ok i don't have any of those problems...yet. I read several Mopar guys using these plugs with great results, the last ones were AutoLite but seem to be burnt out after a month...I have 3 taken out...before I pulled the metal piece out of a SP wire smh to the junkyard tomorrow