The other day, I took the car for a spin..probably an hour or so drive in moderate temperatures.. Well, I was back in the house and after about 10 minutes, maybe 15, after the car was stopped, I noticed liffle puffs of grey smoke. As I watched, they kept coming every 15 seconds or so, and then nothing. It looked like the catalytic converter was just blowing out poofs of smoke..have any of you ever seen this? And also..I know my converter has what looks like a vented covering over it, so I'd expect some heat and stuff, but should it be leaking exhaust?? I'm thinking maybe it's cracked somewhere that I can't see.. Thanks guys

 

sounds like it was taking some drags off of a marlbaro lite ...Well I never heard of one doing this before .hmmm ..My aunt had a 67 camaro and was on the interstate once and accidently ran over a cardboard box and it caught fire ...Maybe there's some sort of piece of trash or debri up under there ? I could be wrong . but just a theory .

 

Nothing up under there..the thing just looks pretty junky. The screen is dented in the middle, which makes me think it may have been damaged internally..and towards the middle of it, it's all blackened. Sidenote, I figure this is normal...but hey, ya never know, so I'll just say it.. When the car has warmed up and you've driven a decent amount, when you stand by the side of the car, you can feel the heat practically pourint out of the side of the car from the converter. And if it's been running a real long time, you can smell the car exhaust from the right side of the car (where the converter is mounted). I think the thing's fried... What do you guys think?

 

Sounds shot to me . Id get it changed .May sound silly , but if its smoking like that , Id be scared of fire ....Wayne

 

Yeah..I'd change it...if I could get one for really cheap and get it installed and welded myself. But I can't, so it'd be just one more added expense which I can't really afford right now, nor wish to pay. I'll just leave it...if it gets bad enough, I'll just totally gut it...get some extra horses from it. No emissions tests around here..wahoo!

 

you may have ran over something , and whatever you ran over could be stuck in that small mesh thing somewhere and it could be causing it to smoke like that .could be anyway ...I'd still replace it , if its smelling like that ..Wayne

 

It is totaly toasted. A few cars back I had the cat actualy burst into flames. Realy cool, but scared the hell out of me. It puffed smoke for a while just like you described.

A stock cat shouldn't coast all that much, and you can install it your self. It doesn't need to be welded. Now if you wanted a high flow it would coast a little more.

 

An aftermarket one can be cheaper than a stock one .I went through this about a year ago . I dont really like mine gutted and I'm about to put on an aftermarket .Just shop around a little , don't buy the first aftermarket one you see ....Wayne

 

dont gut the cat you will still get the turbulence going from a nice round pipe to a big open area then back down to a round pipe. go out and have your local muff shop or someone make you a straight pipe that will bolt on. little louder more power through the whole rpm range.
cheap to do also

 

Yeah, I bought my products for power aftermarket high-flow cat for $60; local shops wanted upwards of $100 for a "stock" one- and those had to be welded! The GM dealer wants even more. You can find a cat that's a bolt-in; then, your only trouble is separating the old cat from the slip-fit join where it meets the y-pipe. A screwdriver and hammer can work well in that situation.

You'd want a "2.5 inch in, 2.5 inch ball flange out" cat. Do a search on this V6 board for Catco, you'll see how it's described...


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

That's a good point rx, about the airflow. Once it gets into that hollow chamber, it'd expand to fill the thing, and wouldn't exactly want to be pushed back into a tiny little hole again.. I might put a new one on...but I'll probably wait until this one starts spitting out chunks of the converter material.. I don't wanna make any more repairs to it unless absolutely necessary..it's just costing too much!

 

well a gutted cat will have issues with flow but when you put a screen like mesh in there as a real cat would have then you just make the issue worse

now on top of just going from a small>>wide>>small space again you have to fight through the cat crap... test pipe the only way to go if you dont have emissions

 

Nixon, you could also wind up plugging your muffler with "chunks of convertor material", then you'll have to replace a muffler, too.



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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

You know, I was thinking about that just last night. And we all know what happens with a plugged muffler.. (Potato in the pipe, anyone?) Boom...not good. Not to mention terrible performance. I still have to find out exactly how worn out it is. If it still has some value, I'm leaving it on.. But if it is literally to the point where it's gonna start falling apart, I'll probably buy a replacement so I'm emissions legal...don't wanna straight pipe it..

 

Honestly, with the way cats are built today, they're much freer flowing than the originals... I think of 'em as an EGR- doesn't rob power, helps emissions, so we might as well have it.


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

CHANGE It ! You dont want it catching your car on fire ....Then that will cost you even more money and heartache cus you lost your thrirdgen ....Wayne

 

Yeah..exactly. Why not? Besides..I'm not building this car into a muscle car or anything, so I don't care about an extra 1 horse. If I can get that old sucker off of there and put a new, cheap hi-flow, it'll probably perform better too..ya think?

 

TomP is right ! ...I plan on taking my gutted one off soon and going high flow .Wayne

 

it will perform much better than a clogged one .

 

Yeah..heh..I just wonder how badly mine is currently clogged.. Hopefully I'll get some harder pulling and more throttle response out of it. Anyone know of a real cheap hi-flow? Don't care about durability or whatever...all I want is a cheap hi-flow converter. And something that'd take an hour or less to install preferrably, since it's gonna be done by a mechanic at $40 an hour. (I don't have the equipment for removing the old one.)

 

I have seen a dynomax one for $60 ...dont know how good it is . But there mufflers are pretty reputable , have one myself

Wayne

 

Yeah..I've definitely heard good things about Dynomax mufflers from all the V-6'ers. And $60 is definitely cheap..all the hi-flows I keep seeing in magazines are $200+!

 

didnt know some were that much

 

The one TomP has and I, also, are great CC.
Don's Hot Rod 800-888-8892 2 1/2" in & out Perf for Power CC's are great.
I have the one I got back in 1990 still on my truck and that truck (my S-10 Blazer) still passed smog with that old CC.
I'd buy another in a heart beat if I needed it on my Firebird.
I'd make a MUCH smoother junction pipe from the factory manifolds to the CC. I just read an old Super Chevy test, where they did that exact idea on a 1985 305 Camaro. IT gained power all thru the RPM range and raised the top RPMS to usable HP. By also porting the stock exhaust manifolds on that 305 Camaro, it gained a total 15 HP on the top end.
I know when I modified my exhaust on my S-10 Blazer, I gained SO MUCH POWER, I was so pleased for the $$ investment I made.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

Yeah...I couldn't believe they got that high either! So, here's my question guys..is there any surefire way to find if the cat is fried? Do mechanics, service stations, etc. have exhaust sniffers that can tell you whether it's doing its job or not, or what? I just wanna make sure that it needs a new cat.. I mean, from what I've seen, it definitely does...but I just wanna double check everything I suspect.

 

By the sure fact that it's puffing smoke and smells is a sure fire way to tell if it's toatsed. If you were able to look inside of it I would bet that the honey comb is a melted blob right now. One word of advice that most shops wont tell you. A cat goes bad becuase the car wasn't running correctly. Give it a tune up, replace the O2 sensor and make sure it's in time. If the car runs rich it will burn the hell out of the cat. Do these things either right before it's changed or right afterwards. Mine was on there so long that I had to take in to have it cut off. which only coast me about $30 for labor they even put my new one on for me.

The bottom line is that it is fried and if it's not taken care you will have to put out even more money to have it fixed. which is what you have been trying to avoid. Taking it to a shop to have them check it then put it back on and tell you that it needs to be replaced. Then turn around and charge you more money to put a new one on will coast you all most twice the amount it would have coast to have it replaced in the first place. The only way to check the condition of the honey comb is to remove and look through it.

You basicly have 4 options.

1. ignore it live with the smell and risk it bursting into flames. = more moeny to fix damage caused by fire or an exploding cat.

2.Have a shop pull it check it put it back on just to tell it's no good. then pay to have a new on put on. = unecesary step which coast extra money.

3. yank it off and replace it with a strait pipe and live wih the smell. = it coast more to have a shop yank it and fit a strait pipe then it does to just replace it.

4. Replace it. you might have to pay labor to have it removed, but it's a small amount.

 

Why does everyone say that cars without a cat smell bad??

My Bird has no odd smell, my friends Olds sans cat smells OK, I know a 92 Buick sans cat that has no odor.

I know a few cars with a cat that smell pretty bad.

Just curious

Dale

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1986 FireBird
2.8L MPFI
1/2 CAI
Gutted Cat, No muffler
Was 700-R4 --> Now T5
**** Great cars aren't bought, they're built ****

 

I have owned 3 cars in my life a 71 camaro, 78 celica and my 87 RX-7

the camaro and celica never had cats and had no bad smell at all. my rx7 always stunk and that is with 3 CATS!!!

I took those 3 cats off it now smells fine and made a big gain on power. I put a test pipe in there and it is louder yes but has a lot deeper tone there. I gave the muff shop the size of the piping I would need and had them put it all together.
cheap way to do it and if you dont have emssions it is the best way to do so. even with a high flow cat you are going to lose performace were the test pipe would give you better gains.



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imports are cool - ricers suck
ICQ 4116192
AIM RXspeed87
Got rotary?
header, intake, ported TB.
soon to have ported intake, lighter rotors,ported motor and a T-66

 

Get hammer
Rap on the CC
IF it rattles, it's busted up inside.
It'll run ya about under $100 total for this job.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

I'll try that as soon as I get the chance.. And as far as the odor thing goes... 2 of my friends have gutted cat cars..a V-6 Fiero that doesn't smell, and an 84' Trans-Am 4 barrel carb that stinks the entire street up. Smells like rotten eggs..pretty nasty.

 

The cat that was on the car when I bought it turned out to be gutted... my car didn't stink, and I passed emissions (at the state's testing area!) three years in a row before I discovered it was gutted. I discovered that when I pulled it off to put my high-flow on!


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

Tom,

You passed in NJ with a gutted cat??? Lucky man. I hear that the laws in NJ are more strict then California. Do you have to go through more then just the sniffer test?

 

Well, I didn't have a hammer, but I banged on it at school with a can of spray paint (needless to say, all I heard was rattling..I'm a moron!), so I picked up an old cassette player and banged it with that. Sounded solid and sturdy..no rattling. Next time I go out with friends, I'm gonna let the car warm up, and get out and see if I can smell exhaust, etc, etc, etc.