may sound like a dumb question but what exactly is the converter supposed to do?

still having issues with the 90 and i feel after all the things i did on the engine that it may be the converter is clogged. had one on another car go bad years ago and symtoms may be the same.

was suggested i take it out and remove all the insides and reinstall it so it appears there is one there for inspection purposes.  on my 75 all the emission stuff has been removed as with the way i registered it there is no emissions testing on it.

my question is, if i do "clean out" the inside, will it have any adverse affects on the motor or should i just order a new one?

thanks for any thoughts


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LIFETIME MEMBER #97
THE DYNAMIC DUO

Well, simply put(since that's the only way I can 'splain it), the converter causes a chemical reaction in the exhaust gases that makes them less harmful to the planet. Removing the cat(s) will also effect the way a car runs...sometimes in positive way, but most times not.
The '90 car is way more computer run, so anything that effects the "smell" of the exhaust is gonna effect the running. I would recommend replacing the cat(s), not take them off. There are high-flow cats, too, that put way less restriction in the exhaust...those are good, but they can be a bit pricey.

If the car is running out of steam when you get down on the go pedal, and sorta feels like it's running out of gas, it is probably a converter stopped up. They normally run slower the more gas you give it, then, as you let up on the pedal, it'll speed up some.
hth

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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

i see you know ed zacary too cause that's ed zacary how the car is running. when it heats up especially i have to "feather" the gas pedal and can get some speed. if i punch it, it loses basically everything and that little nash rambler could do the same to me as it did to the caddy. thanks for the info.

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LIFETIME MEMBER #97
THE DYNAMIC DUO

Hey Dave, put in a high flow cat, I did mine when I redid the exhaust and it made a BIG difference in the way the car ran.

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Lifetime Member #116
Dave's '82

   

So do you have one for sale Mr. Mooney when ya stick in the ZZ4? I would think the converter wouldn't be a requirement st that time.

Maybe you can help a brother out an he can oblige with a payment in return.....

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[QUOTE=DaveM]Hey Dave, put in a high flow cat, I did mine when I redid the exhaust and it made a BIG difference in the way the car ran. [/QUOTE]

thanks for the info dave. before all this stuff started it was running pretty good although now that i look back at it it may have been on its way out before and then when the car was blowing clouds of black smoke out the back finished it off.

the dilemma here is this: with a wife, a cat, an escalde, two vettes, etc. to keep in top shape, with the car running as it did before this happenned, as joel said they can be pricey, is it worth twice the price for a high flow?

was your converter good before you changed it and that's how you noticed the improvement or was it going bad and the new one cleared the problem up whereas a regular one might have done the same? not trying to doubt your info but just trying to justify the cost difference to myself.


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LIFETIME MEMBER #97
THE DYNAMIC DUO

I haven't done it to a Vette, but most of the GM stuff before 95 only has a single O2 sensor ahead of the Cat and does not have a monitoring sensor after the Cat.  So, it has no idea if you have cleaned the cat out or not. All it know is that you now have less of a restriction than before. Similar to putting on a low restriction exhaust.  The nice thing about the GM computer system is that it will adjust to deal with the change in backpressure. So, I would try that first.

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C3: 1979 Corvette Coupe, Auto, L-48, Red/Doeskin (my wife's fave);

But...will it pass a sniffer test?

It's also illegal to do it, but...it's only illegal if ya get caught!

It might be worth a shot to pull it off and gut it, to see if that is the problem. Then, you could get a replacement cat as funds would allow....Adams' Apple2007-10-01 19:39:45

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Joel Adams
C3VR Lifetime Member #56    
My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

i was thinking about "cleaning" it out but i figured if i was going to go through all the trouble of removing it i will just replace it. as far as i know it is not like they burnt out quickly. for right now i am going with a standard direct replacement as it is half of what the high flow is. partially doing this for the cost and when this thing runs good it goes like a bat out h**l. i can always swap it out at a later date if i change the exhaust. i appreciate all the answers i have gotten and will keep the info tucked away for later use.

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LIFETIME MEMBER #97
THE DYNAMIC DUO

[QUOTE=Tuxblacray]So do you have one for sale Mr. Mooney when ya stick in the ZZ4? I would think the converter wouldn't be a requirement st that time.

Maybe you can help a brother out an he can oblige with a payment in return.....[/QUOTE]

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Lifetime Member #116
Dave's '82

   

thanks anyway dave. don't even know if it would fit the 90 as the inlet is 3". here is an update though. i have a feeling that this situation has happenned before to one of the POs.  I picked up the direct fit converter after work and after having a cup of coffee with wife went out and started to work on replacing it.

took it out of box and matched it up against the one that's in there and to my surprise the converter itself is almost twice the size as the one in there. the overall length is the same from end to end. so maybe this will be my high flow converter putting in the right size.

the reason why i think this has happenned before is number one the size difference and whoever installed it, had a clamp on the front and only welded the the bottom half of it  and was not  even a  good  welding job.  i kind of figure  they used the cheapest one they could find and never realized the secondary ground strap was missing from the distributor  so after a while the problem arose again except this time i had the car and no knowledge of it.

hopefully after all the aggravation this caused it will be the end and it wil be running as it should. thanks for everyones thoughts and help. will let you guys know how i made out when i get it done.

dave


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LIFETIME MEMBER #97
THE DYNAMIC DUO

I am going to ask a potentially dumb question.  Does your exhaust smell alot worse with the cats cut out? 

[QUOTE=gurtz]I am going to ask a potentially dumb question.  Does your exhaust smell alot worse with the cats cut out?  [/QUOTE]

I think we have just gotten use to the smell of newer cars with cats and whatever else they do to them with all that crap under the hoods.
My sure does smell different, but the cats where in a box behind the seat rather than under the car, so I can't compare.

My wife says I stink every time i come back from a ride. She just don't like my new purfume.
Jeffm2007-10-07 06:45:43

on my 75 which doesn't have them the exhaust used to smell a lot. believe it or not i switched from using a cheap premium gas to a name brand and that cut it down a lot. still has an odor to it but here in nj they are adding ethanol so that may have an effect. anyway the exhaust is behind me so it doesn't bother me. seriously i think the smell comes mostly from the additive.

getting back to the 90, i went out and got the old converter out and the pipe was a little out of round plus the old weld was there was going to drop the y  but couldn't get one nut undone and it was getting late so i stopped.

went inside and showered and started thinking about the way my luck is and figured if i just replace the cat, the precats would be clogged and if i just replaced the front half the back half would start falling apart so i am replacing the whole system.

i am getting the y pipe without the precats and it comes with a high flow converter and from another place getting the rear y pipe with low backpressure mufflers.

this way i know the whole system will be new and i won't be doing any work twice. will let you know how it turns out when the parts come in.


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LIFETIME MEMBER #97
THE DYNAMIC DUO

[/QUOTE]

My wife says I stink every time i come back from a ride. She just don't like my new purfume.
[/QUOTE]

my wife complains about my exhaust stinking too. only thing is i don't think she is talking about the exhaust from the car.
eddie208752007-10-07 06:54:30

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LIFETIME MEMBER #97
THE DYNAMIC DUO

The Blacray definately has an odiferous quality comming from the tailpipes that can be taken as "That Thar Sitnkz!" Kinda a mix tween fuelz that formz somefin new maybe Eggsoline?

No matter he runs purty good an ah haint gonna mess with him as long as he haint broke.

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I hear you all and thanks!  I have an old 67 vehicle with no cats and I never smell like exhaust.

I had mine removed and straight pipes run to my Monza performance mufflers, it feels like my 77 has 50 more horses pulling her and she sounds really great. Gene gs77vet2007-10-08 07:53:34