Clogged cat ?

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AdamR

AdamR

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Any way to tell if a Catalytic Converter is clogged other then ripping it out ? My truck hasnt been running right the last few weeks. low on power bad gas milage. Today as Im driving down the highway the truck started running real rough. So bad I wasnt sure Id make it home.

It hasnt been running any hotter then usuall but the exhaust sound strange like its restricded. Also I pulld the plug wires 1 at a time to see if I could find a bad cylinder but it mad no differance in the way it ran.

Im guess either a clogged cat or a burnt exhaust valve. Hope its the first one.
 
If the exhaust sounds like it's blowing through a bar straw, chances are good it may be the cat. Have someone rev the engine (within reason) and place your hand near the exhaust pipe opening and feel for pressure. You can also try and craw under it and bang on the convertor with a rubber mallet to listen for any kind of rattling or clunking. The insides of a catylitic convertor is a honeycomb. When it breaks down it will collapse and clog the exit.

I don't know what the inspection procedures are in Conn. but you can buy a "test" pipe and bypass the cat, or you can just go to the wrecking yard and grab one. New ones range from expensive to oh-my-gawd expensive.... :shock: You might luck out and find an aftermarket unit.

Let us know how you make out. :salut:
 
Thanks John. I'll look in to it more in the morning.

I may just cut the thing out and worry about a replacement when they figure out what the hell is going on with the emssions testing around here.
 
Have you tried hairball medicine? Our old cat will --------------NOTE TO SELF "read post before answering. Oh man, I feel like an idiot, and there is good reason. :D Ray
 
I use to use a vacuum gauge hooked to the intake. As you rev the engine up slowly the gauge would keep falling off. It was a good indication the cat was getting plugged.
 
LM23P9B said:
Have you tried hairball medicine? Our old cat will --------------NOTE TO SELF "read post before answering. Oh man, I feel like an idiot, and there is good reason. :D Ray
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:laughing: :evil4: :laughing:
 
ya know Im wondering if I got a tank of crappy gas.

It seems to clear up alittle when you give it some gas. Ofcoarse I just filled the tank.
 
I've had to replace two cats in two months :x .
What milage do you have on your truck 80,000-100,000+??? if so and you've never replaced the cat it's time.
Just don't get one of them hi-flow cats especially if your smog tests are as tough as here in California. There cheap as hell, don't last very long at all and will give ya a nice big FAIL on your smog test
 
Here kitty-kitty. :axe:

I see from another thread your truck is a Chevy Blazer. From my experiance with GM stuff, with 161k miles on it that cat is history. It has probably crumbled and all the pieces have made their way to the muffler and that is where your clog is.
 
fastbackcuda said:
You think the clogg may be in the muffler ?
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I told ya Adam, crawl under it a rap the cat with a rubber mallet. If it makes noise hit the muffler too. Hell, when your done, come on down to Queens and give ME a rap with the mallet. I know I'll definitely be makin noise today..... :tongue:
 
You think the clogg may be in the muffler ?
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I've had it happen twice (Fiero and Grand National). The catalyst breaks down into pea size chunks and travels down the pipe to the muffler where they get caught. Use a rubber mallet and tap on it. If it rattles, that's your problem.
 
Yup its rattleing. When I beat on it with a hammer you can hear the crap in it. Also its pulsating when the truck idles.
 
The guy across the street has a 2001 Dakota with almost 200,000 miles on it. He just had to replace the cat on it, he went to a Dodge dealer to get the parts.

Almost $800... For the parts alone!
 
I just replaced my cat (98 Chevy truck 165,000 miles) for the same reason. Mine has the cat & Y-pipe as one unit ($500). I took it off & gutted it out to stop the rattle, which resulted in an error code due to two O2's before & one after the cat, so a "Test pipe" will not work, unless you replace the rear O2 sensor w/ a chip that Jegs sells for around $80. Tuffy Muffler welded in a replacement for $120. Solved my rattle & error codes, but I may still have a clogged muffler.
 
I just picked up the muffler, $25. Im just gonna punch the cat out for now seeing the emissions testing here is al messed up. I replace it when I have to have it tested. Its $250 for the cat.
 
fastbackcuda said:
I just picked up the muffler, $25. Im just gonna punch the cat out for now seeing the emissions testing here is al messed up. I replace it when I have to have it tested. Its $250 for the cat.
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Glad to hear you might have found it. When the muffler/cat sounds like it's full of pebbles and sand, it may as well be. Time to replace`em.

Let us know the results. :thumrigh:
 
Well it wasnt a clogged muffler. The crap inside of it was just what was left of the rotted tubes. Took it out cut it open and it was hallow.Thats why it sounded funny. Exhaust bouncing everywere. The cat looked fine aswell.

To make things worse the replacement muffler was wrong. Pipes on the muffler were the same size as the exhaust pipes so I couldnt slip the pipes inside it. Now I have a rigged on muffler tlll I have the time and money to fix it. may aswell just replace the entire system and be done with it.

How ever that still leaves me with a crappy running truck. I have no idea what it could be. It hasnt tripped the engine light so looking for codes wont do me any good.

It runs like crap at part throttle and cleans up at around 2500rpm. As sson as it shifts and the rpms come down it runs like crap all over again.
 
If that thing is injected, maybe the injectors are clogged. Lucas makes a decent fuel injection cleaner. Mercedes recommends the one from BG products.
 
Gotta check and see if the injectors are dripping at idle. Sappose to be a comman problem. They drip and the motor loads up. Wich would explain wht it clears up with rpms.
 
I wish you would have let me listen to that thing while i was there....The Z did that but not terribly. Does it crank alot when warm yet start up instantly when it's cold? Leaky injector(s) def might be flooding a cylinder or two. Maybe some top engine cleaner couldn't hurt either. It ran great on the way up, and correct me if i am wrong, but it sat for quite sometime, right? Something could just be plugged; gummed up. I would shoot for a map or tps, but you say no codes....

:shock:
 
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