There goes the catalytic converter

[irowiki]

For a while I had noticed rattling at lower RPM's but could not pin down the source.

On the way to work, the road noise coming off the car suddenly tripled! Once I got off the highway I tested some revs and sure enough, the engine was much louder, but still running fine.

I looked underneath once I got there and there was smoke (exhaust?) coming from the catalytic converter. I think it is hosed.

So question, can I still drive the car without damaging anything, and is this an easy fix to replace or bypass it?

[danzo]

You can certainly do without the cat if your local regs allow it (in near-lawless NM I bet you're OK). I removed and traded mine a few years ago for a window regulator for my other car. I had a 'test pipe' made for 30 Somalians which is really not much louder than stock, and I can still use the otherwise stock exhaust parts. Party on.

[irowiki]

There's no emissions testing here. I have to guess the cat wasn't even doing much for a long time!

Where do you get such test pipes made? A reman cat is $50 or so on ebay.

Am I okay to keep driving it until I do something?

[danzo]

I imagine that any muffler shop around you will do a test pipe since you don't need to do emissions. With an exhaust leak you may be breathing some fumes until you get the leak(s) fixed. Your mental health's monetary value can only be determined by yourself.

[Petros]

you will not harm anything in the car by driving it as is. You can cut the old cat out and with a couple clamps and a length of pipe from an auto parts store you can by-pass it yourself. If it is too loud you could get a "fix it" ticket, depending on the local gendarmes.

Most states, like mine and likely yours, do not require keeping all of the emissions systems working after the car is 25 years of age, however there are federal laws that do not allow you to disable the systems. The practical matters are there is no enforcement process other than the EPA threatening to fine repair shops (unconstitutionally) if they have an active business of removing cats for their customers.

So for about $40 many muffler shops will do it, if they do not think they will get nailed. If you find a repair shop where few or no-one speaks English (which should not be hard to find there), they will likely do it for you for cash. Tell them in Spanish that it is a "temporary repair" to drive it home, until you can afford a permanent repair.

[irowiki]

I'd like to add that this happened the day after I set the timing to 10* instead of 5*, do you think this is related? I noticed much better responsiveness and a bit more power after doing the change, then bang!

I have to guess it was a coincidence as it has been rattling for a while.

[dlb]

yes, if it was aready going then it was just a matter of time and it's only a coincidence that it happened after you advanced the timing. unless you were drag racing a lot with your newfound power!

[irowiki]

The only drag racing I do is "slowest car out of the stop light wins!" I love how impatient people get at lights when they are behind me.

[ARCHINSTL]

The only drag racing I do is "slowest car out of the stop light wins!" I love how impatient people get at lights when they are behind me.

My gson commented on Goldie's acceleration once, and I reminded him of who won the tortoise and the hare contest.
Of course, I received a "Huh" and a blank stare...
Tom M.

[splatterdog]

The only drag racing I do is "slowest car out of the stop light wins!" I love how impatient people get at lights when they are behind me.

My gson commented on Goldie's acceleration once, and I reminded him of who won the tortoise and the hare contest.
Of course, I received a "Huh" and a blank stare...
Tom M.

Put some snow on the ground, I always win.

Don't throw the old cat away(if it still has ANY guts). Prices are down now, but I've gotten over a hundo for a T4 cat. Many places won't touch a catless car. But if it's already gone, then they aren't really tampering. Just patching a big leak...

These like most other cars do get louder without it. A small muffler does wonders in it's place.

[tercel4wdrules]

With a former T4WD wagon I remember hearing a distinct rattling sound in a certain RPM range. I took it to a muffler shop and sure enough the cat converter had fallen apart and the broken internals ended up in the muffler. So, I took the opportunity to just upgrade to a 2" catback exhaust. Therefore, if you suspect the catalytic converter is falling apart, you may want to do something about it before broken pieces end up in the muffler or elsewhere in the system.

[MR2Di4]

The only drag racing I do is "slowest car out of the stop light wins!" I love how impatient people get at lights when they are behind me.

My gson commented on Goldie's acceleration once, and I reminded him of who won the tortoise and the hare contest.
Of course, I received a "Huh" and a blank stare...
Tom M.

Put some snow on the ground, I always win.

Don't throw the old cat away(if it still has ANY guts). Prices are down now, but I've gotten over a hundo for a T4 cat. Many places won't touch a catless car. But if it's already gone, then they aren't really tampering. Just patching a big leak...

These like most other cars do get louder without it. A small muffler does wonders in it's place.

Actually people are genuinely surprised when I smoke the front tires leaving a light, even chirping them going to second. Damned thing winds up pretty quick until 3rd gear...

Although, I'm beginning to suspect my cat is shot too, so when I redo my failing exhaust system to make my beater sound like new it will go bye bye.

MR2Di4

[irowiki]

Alright, tried to jack the car up last night to get a look, except my brand new jack was bad and it hardly got the wheels off the ground. Got some pictures and video while I was at it.

The "distinct rattling sound" I was hearing at lower RPM's is gone, replaced by a few clunks and bangs. It would seem to be leaking more towards the exhaust manifold instead of the Cat, but if say the cat plugged, would that cause it to pop further upstream?

I'm going to see about getting a better jack and perhaps trying to detach stuff to see where it is leaking! I want to fix this myself but I am unsure if I can, I may have to break down and visit a muffler shop



http://youtu.be/lik8KFWbYno Engine noise while stopped
http://youtu.be/l3C6H62H8fY Engine noise while driving

[Petros]

looks like after market cat, you can fix it yourself. Soak the clamps in penetrating oil and remove the clamps and fight the old cat out. Than install the correct length of straight pipe and reuse the old clamps.

[irowiki]

So I'm not even sure it is the cat anymore! Or it is, and caused other issues. Did some testing last night, plugged off the muffler with a rag, and the engine idle didn't change at all, in fact, it revs up about halfway before starting to struggle.

As soon as I plugged the muffler, my wife, who was standing over the engine bay, noticed a cloud of fumes by the smell. So I got under the car, smelled around, didn't smell anything there either.

It would seem it is coming from the section of pipe in between the manifold and the cat. Any tips for getting those bolts off which hold the pipe to the manifold? Also for getting a new pipe, not sure this will be cheap

I'm starting to suspect maybe the cat got clogged, then the pipe north of it popped, and now the cat is clear enough to allow some passage.