General GM Chat When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made. Chat about all things GM (and related cars). Off-topic stuff should be in the Lounge, and all Model specific mechanical problems should be posted in the proper forum.

What causes Cat Converters to plug up?

Thread Tools
 
Search this Thread
 
Old Dec 9, 2006 | 03:49 PM
  #1  
crzydmnd72's Avatar
Thread Starter
Senior Member
Certified GM nut
 
Joined: Jan 2004
Posts: 1,656
Likes: 0
crzydmnd72 is on a distinguished road
Default What causes Cat Converters to plug up?

Local Dealer has a 95 SE, says on the windshield that it "Needs Cat Converter" Please correct me if I am wrong, but isnt that USUALLY a symptom of something else not working right, ie burning coolant, cylinder not firing, poor maintence? Its a nice car otherwise, condition wise, I havent taken the time to visit with them or hear it run though. Its probably worth what they are asking for it in its current condition. MrsCrzy pointed out that it could have a whole host of other problems unseen and prefers to stick with our trusty LE'* and spend the $$$ on what we already have.
Reply
Old Dec 9, 2006 | 03:58 PM
  #2  
Hans's Avatar
Senior Member
True Car Nut
 
Joined: Jul 2004
Posts: 7,545
Likes: 1
From: Twin Falls, Idaho
Hans is on a distinguished road
Default

severe improper a/f ratio. several dead sensors, causing a rich condition.



or a broken cat, I've had one before. it rattles when you hammer on it.
Reply
Old Dec 9, 2006 | 04:02 PM
  #3  
crzydmnd72's Avatar
Thread Starter
Senior Member
Certified GM nut
 
Joined: Jan 2004
Posts: 1,656
Likes: 0
crzydmnd72 is on a distinguished road
Default

Originally Posted by Hans
severe improper a/f ratio. several dead sensors, causing a rich condition.



or a broken cat, I've had one before. it rattles when you hammer on it.
Forgot to mention that my father looked at it, they bought a beater at the same dealer for my sister to drive. Salesman told him that it had NO get up and go, so they figured the cat was plugged. They passed on it, she needed something to drive that didnt have to go straight to a shop. BTW, asking is 900 bucks. Maybe I can go look at it after a bit.

OTOH, 900 bucks in parts goes a LONG way towards fixing up the current LE'*
Reply
Old Dec 10, 2006 | 12:12 AM
  #4  
Bugsi's Avatar
Senior Member
Posts like a Camaro
 
Joined: Nov 2002
Posts: 857
Likes: 0
Bugsi is on a distinguished road
Default

Defective materials in manufacture can cause the inner material to break down and clog the cat. But if your dealership is doing things like just presuming the cat is plugged because a car has no get up and go, you should not buy a car from this dealer without getting the car thoroughly inspected by a qualified shop. In my entire lifetime I've experienced one plugged catalytic converter. I'd personally wager that plugged catalytic converters are one of the least common causes of a car "lacking get up and go", whereas more serious engine problems are probably *VASTLY* more common. Worn piston rings, worn valves, worn bearings, worn cam, being the most serious, and typical of things that a dealer might try to cover up by claiming ignorance and blaming on a plugged catalytic converter.

It begs the question, if the only thing wrong with the car is a plugged catalytic converter, why didn't the dealer just put a new catalytic converter on it?
Reply
Old Dec 10, 2006 | 12:44 AM
  #5  
crzydmnd72's Avatar
Thread Starter
Senior Member
Certified GM nut
 
Joined: Jan 2004
Posts: 1,656
Likes: 0
crzydmnd72 is on a distinguished road
Default

Originally Posted by Bugsi
Defective materials in manufacture can cause the inner material to break down and clog the cat. But if your dealership is doing things like just presuming the cat is plugged because a car has no get up and go, you should not buy a car from this dealer without getting the car thoroughly inspected by a qualified shop. In my entire lifetime I've experienced one plugged catalytic converter. I'd personally wager that plugged catalytic converters are one of the least common causes of a car "lacking get up and go", whereas more serious engine problems are probably *VASTLY* more common. Worn piston rings, worn valves, worn bearings, worn cam, being the most serious, and typical of things that a dealer might try to cover up by claiming ignorance and blaming on a plugged catalytic converter.

It begs the question, if the only thing wrong with the car is a plugged catalytic converter, why didn't the dealer just put a new catalytic converter on it?
really good point. For a 200 dollar converter, they could get 2k for it. At least according to KBB.com Must be something else going on. I may check into it just to see, reckon they will let me pull plugs, maybe even run a comp test ?
Reply
Old Dec 10, 2006 | 09:40 AM
  #6  
clm2112's Avatar
Junior Member
 
Joined: May 2006
Posts: 0
Likes: 0
From: BonnevilleHell
clm2112 is on a distinguished road
Default Re: What causes Cat Converters to plug up?

Originally Posted by crzydmnd72
Local Dealer has a 95 SE, says on the windshield that it "Needs Cat Converter"
The Mrs. plan is actually a pretty good one...as Mrs clm2112 pokes me in the ribs.

Otherwise, I would take a look under the car and see if the cat is actually there or ask the dealer what the heck the message on the windscreen means. (It'* possible someone straight-piped the exhaust...though, I think it'* against the law for a dealer to knowingly sell one that has had the emissions gear tampered with.)
Reply
Old Dec 10, 2006 | 02:21 PM
  #7  
Greyhare's Avatar
Senior Member
Posts like a Northstar
 
Joined: Oct 2004
Posts: 533
Likes: 1
From: Purgatory
Greyhare is on a distinguished road
Default

Originally Posted by crzydmnd72
Salesman told him that it had NO get up and go, so they figured the cat was plugged.
Sounds to me like the dealer has no clue what is wrong and is just guessing.
Reply
Old Dec 10, 2006 | 02:57 PM
  #8  
popatim's Avatar
PopaDopaDo
True Car Nut
 
Joined: Jan 2005
Posts: 4,957
Likes: 4
From: NY
popatim is on a distinguished road
Default

The whole thing doesn't make much sense... wouldn't that dealer have to guarantee the beast under for a time under the lemon law?
Reply
Old Dec 10, 2006 | 07:41 PM
  #9  
F14CRAZY's Avatar
Senior Member
Posts like a Northstar
 
Joined: Apr 2006
Posts: 549
Likes: 0
From: Dimondale, MI
F14CRAZY is on a distinguished road
Default

From what I've read, a plugged cat would limit power at high RPM
Reply
Old Dec 10, 2006 | 08:29 PM
  #10  
Logan's Avatar
Senior Member
Certified GM nut
 
Joined: Feb 2004
Posts: 2,246
Likes: 0
From: MI
Logan is on a distinguished road
Default

Originally Posted by Bugsi
Defective materials in manufacture can cause the inner material to break down and clog the cat. But if your dealership is doing things like just presuming the cat is plugged because a car has no get up and go, you should not buy a car from this dealer without getting the car thoroughly inspected by a qualified shop. In my entire lifetime I've experienced one plugged catalytic converter. I'd personally wager that plugged catalytic converters are one of the least common causes of a car "lacking get up and go", whereas more serious engine problems are probably *VASTLY* more common. Worn piston rings, worn valves, worn bearings, worn cam, being the most serious, and typical of things that a dealer might try to cover up by claiming ignorance and blaming on a plugged catalytic converter.

It begs the question, if the only thing wrong with the car is a plugged catalytic converter, why didn't the dealer just put a new catalytic converter on it?
You make it sounds like it is doomed to MAJOR engine work. Lack of get up and go could ALSO be dying fuel pump, bad FPR, bad wires, bad plugs, clogged injectors, very very dirty air filter, etc.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
EagleKammback
Lounge
10
Nov 15, 2007 11:11 PM
SSEimatt93
Audio (and aftermarket electronics)
5
Sep 4, 2004 12:17 PM
Performance, Brainstorming & Tuning
0
Aug 3, 2003 06:16 PM
94bonnyV
1992-1999
15
Aug 2, 2003 11:19 PM




All times are GMT -4. The time now is 12:43 PM.