How do you know if your catalytic converters starting to bite the dust?

[BDShort]

I've been really attentive to sounds from my beauty and I've noticed a sound from underneath i believe underneath the drivers side. Sometimes it would shake the car so I assumed it was the rubber hangers holding the exhaust going bad.

Replaced the hangars, and the shake is gone as far as Ive noticed, but the sound is still there. It's a metal sound, not quite sure on specifics, but I believe it to be the converter.

Whats a few tests I could run to know? I read when it does go out, it would sound like marbles being shaken around? What happens functionally to the car when it does kick rocks? Whats the average price of the part for repair?

Thanks to anyone who replys and sorry for all the questions

 

[rs2k]

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Do you smell and sulfur? Rotten egg / Lighting a match smell? Does your car smell more like gasoline or is it acrid and sharp? Cats make your exhaust smell very sharp and acrid when they are working correctly. If they are not working correctly your exhaust tends to smell more like gasoline.

Hit the cats with a rubber mallet or really hard with the bottom of your first and listen for rattling inside, but don't hit it so hard as to break the honey combs inside.

As long as the cats aren't plugged your car will run just find with bad cats.

To replace all FOUR cats you're looking at at least $500. One shop quoted me a ballpark of $1100. Not worth it unless you have to pass an emissions test...

 

[BDShort]

No smells, just a distinguished rattle. Enough to scare away anybody who'd want to buy.

Already had a muffler needing replaced for inspection, unfortunately, im a jack of all trades minus welding. If it is the cause I'm probably gonna just buy a torch from the auto store and do my worst. I figure a bad cat wouldnt cause a shaking though?

 

[rs2k]

If the front cat blew up and sent crap into your second cat then it could cause shaking because it would be impeding exhaust flow.

Try this: http://www.youtube.com/watch?v=d-jp1IIJVVk


I bought a mig welder and a reciprocating saw from harbor fright for the same reason. There's very little room to work with under the car. If you remove the exhaust you can probably do the job without too much trouble. I couldn't get one of the exhaust bolts out so I finally took it to an exhaust shop someone recommended.

Once you're inside the exhaust one way to fix a bad cat is to use a crowbar. You didn't hear that from me though. *cough**cough* gut them *cough**cough*

 

[BDShort]

Well I don't have an exhaust leak that I know of, but I do have/had a check engine light code. I had one pop up and I can't recall what the code was but I know it was fuel/emissions. I replaced a sensor just behind the front bumper in front of the driver side wheel, unplugged my battery, and haven't seen the light on.

When i turn the car to accessory mode there's a check engine light. (not sure if that's standard or if it means the issue is still there)

Could an O2 sensor be the cause? Granted the rough knocking sound and random shake couldn't' possibly be an issue caused by the sensor, but maybe?

 

[rs2k]

A clogged cat wouldn't cause a leak. It would cause excessive back pressure.

Knowing what that code is would help tremendously. In the future make sure you record what code you get. How bad is the shake? A misfire can cause a LOT of shaking if the conditions are right. When I had bad plug wires and was getting misfires while towing if was like going down a dirt road with severe washboard. It made the whole car rattle.

A check engine light is normal with the key on and engine off.

I'm not sure which sensor you replaced. What engine do you have?

 

[BDShort]

My muffler had a leak, I know cats are usually for NOX. I can't recall the code because once I replaced the sensor the light went away once I reset it with the battery.

It's a v6 SOHC. I can't remember what the sensors called, but I know it deals with the fuel lines in the front. Bolted on with 2 bolts, fairly simple and fast to remove, has 2 lines running to it.

I'm almost certain the sound is the cat based off the location of the sound. Is there any other possible scenarios for a knocking sound underneath the drivers side about where my feet would rest?

 

[bill06447]

Check the heat shield surrounding the muffler. Stick your hand around it (cold!) check for looseness or broken spot welds. I had to take mine off pending a replacement exhaust, the rattling shield about drove me buggy!

Bill