Catalytic converter issue

[ifcar]

Extended mountain driving in western VA took its toll on the Caravan's catalytic converter yesterday. The engine started misfiring, accompanied by the splendid orange illumination of the CEL, and the car's maximum speed up one particularly steep hill dropped to 10 mph to 5 mph before it quit outright. There was a pronounced burning smell, the cat had definitely overheated.

However, the problem seems to have since vanished. The car started and ran normally after about half an hour, and it has done fine since. The CEL has even gone off.

Is my only necessary course of action to avoid particularly hilly areas to prevent future issues, or will I need to have some repairs done? Bear in mind that long-term damage is not a concern, I am treating the Caravan essentially as a disposable car to last only the next year or two.

Thanks in advance.  

[JWC]

Once the catalytic converter cools down, you can keep going. I've seen customers drive Jeeps in to the dealership, commenting it took a couple of hours because they had to stop every 15 miles to let it cool and they didn't want pay for a wrecker call. (If it was out of warranty, I would just send them down the street to the muffler shop. I wouldn't pay $600 for a cat when you can get one down the street for a couple of hundred installed).

Are you sure it was the cat? When I worked for Dodge, I used to get a couple of phone calls from customers in the NC mountains complaining about losing power. The burning smell would turn out to be trans fluid boiling out of the transmission.

[ifcar]

I'm almost certain. Looking under the car, it was clear that the cat was visibly overheating. And the engine shouldn't misfire for a transmission fluid issue.

After verifying my diagnosis, would the $200 or so for a new cat be worth it?

[JWC]

I'm almost certain. Looking under the car, it was clear that the cat was visibly overheating. And the engine shouldn't misfire for a transmission fluid issue.

After verifying my diagnosis, would the $200 or so for a new cat be worth it?

It can be an early sign of a converter failing, it is probably partially plugged up. Whether it is worth it.....

It apparently is happening under extreme engine load, such as driving in the hills.  May not become an issue for a while if you stay on flat ground.  Eventually though, you'll have to address the problem.

[ifcar]

It was constant mountain driving, most of it with the a/c compressor running (for the defroster). as long as it continues to drive well around the relatively flat DC area, I won't sink much, if any cash into it. Thanks. :)

[280Z Turbo]

Just gut it out.

But you didn't hear it from me. :ph34r:  

[Run Away]

The van is newer than '96, meaning it's OBDII.

Gutting the cat would cause the check engine light to be on permanently, and also probably cause the computer to throw a fit and either do the same thing as it was doing there (cutting all power), or just defautl to the "safe mode" and run like crap.

[280Z Turbo]

The van is newer than '96, meaning it's OBDII.

Gutting the cat would cause the check engine light to be on permanently, and also probably cause the computer to throw a fit and either do the same thing as it was doing there (cutting all power), or just defautl to the "safe mode" and run like crap.

I am aware of that, I was only joking. Gutting the cat is the first thing a redneck mechanic does when something goes wrong!

I have no cat on my Z engine because the 02 sensor is just after the turbo so it is unaffected.

Before I replaced my 1976 engine I gutted the cat because it was clogged with oil. I honestly didn't feel much improvement, but I could smell more exhaust fumes. Contrary to popular belief, cats really don't hurt kill hp so I can't recommend removing them, even in a no smog state like mine.

Anyway, when it comes to beaters, I say if it runs today it's good enough! Whether or not it runs tommrow is in God's hands! I wouldn't even worry about it if it runs fine now.

[SaltyDog]

The van is newer than '96, meaning it's OBDII.

Gutting the cat would cause the check engine light to be on permanently, and also probably cause the computer to throw a fit and either do the same thing as it was doing there (cutting all power), or just defautl to the "safe mode" and run like crap.

Contrary to popular belief, cats really hurt kill hp .

<_<  :blink:  

[Run Away]

I am aware of that, I was only joking. Gutting the cat is the first thing a redneck mechanic does when something goes wrong!


Before I replaced my 1976 engine I gutted the cat because it was clogged with oil. I honestly didn't feel much improvement, but I could smell more exhaust fumes.

Good!

When I replaced my exhust (eliminating the cat), I noticed the burning smell was gone, and my mpg jumped up by 3 mpg.

Contrary to popular belief, cats really hurt kill hp so I can't recommend removing them, even in a no smog state like mine.

:blink:  

[280Z Turbo]

Wow! Gee whiz! 280Z made a typo!

[SaltyDog]

It's not the typo that I was  :blink: ing at, but what you said.

[Run Away]

Yeah I can see that, but I can't tell if you're trying to say

" Contrary to popular belief, cats really hurt hp  "

or

" Contrary to popular belief, cats don't really hurt hp "

Because popular beleive goes both ways from I've heard.

[280Z Turbo]

Okay...look at the context:

"I can't recommend removing them, even in a no smog state like mine"

6 posts over 1 word. :D

I fixed it, so you don't need to worry about it now. :)

[Run Away]

Without cats you can throw flames.

Especially on rotary engines.

[280Z Turbo]

Without cats you can throw flames.

Especially on rotary engines.

You probably can, but you probably shouldn't be able to. That must be due to a lack of back-pressure.

I've run temporary stub exhaust systems on a couple cars with no flames.

[Run Away]

The cat is a bunch of small screens, it catches all the raw fuel and unburnt gases inside it and burns them there = no flames.

Without a cat, any unburnt fumes/fuel can travel all the way out the back.

My car with no exhaust after the cat (so just the header, downpipe and stock cat) didn't throw flames. My car now with a muffler and no cat or resonator can throw small flames sometimes. Much more back pressure with the muffler.

Turbo cars can throw alot of flames too, since boost requires more fuel, then when the throttle closes and boost is gone the A/F goes pretty rich and some fuel escapes unburnt.

I think the way rotaries are designed is what makes them throw flames the way they do, but it's the same thing happening (unburnt fumes/fuel).

[ifcar]

The van is newer than '96, meaning it's OBDII.

Gutting the cat would cause the check engine light to be on permanently, and also probably cause the computer to throw a fit and either do the same thing as it was doing there (cutting all power), or just defautl to the "safe mode" and run like crap.

The van is a 96, but what you're describing sounds accurate.  

[Run Away]

I worded that incorrectly anyways, OBDII was mandatory on all 1996 MY cars and newer.

[saxonyron]

Just gut it out.

But you didn't hear it from me. :ph34r:

Ahh, fond memories!  Back in college, my friend's crappy Mustang II "Fastback" (nothing "fast" about that car except it's depreciation) had the cat fail and overhead to the point of melting all those little honeycomb screens.  Talk about back-pressure! My driveway became a crime scene as we reamed out all those little chunks of cat gut.  Car ran perfect afterwards, and even passed Massachusetts emission test (This was back in 1985 or so, so not as strict, obviously.) (BTW, at least the pitiful Stang had a 4 spd manual, so you could pretend to drive fast!)  :D

Iffy, I'd save the dough if you feel like a minor gamble.  If you typically don't stress the engine, forget it for now.  Of course, if she overheats and fries, then you do the honorable thing and get the cheapest POS aftermarket cat you can.