Plugged Cats

[welderdave]

Hey im new here so hello to everybody. I have an '05 sierra 4wd with the 5.3l engine. Recently the check engine light came on and the truck was burning very rich with a pile of soot from the tailpipe on the ground. I changed all the plugs and they looked good for wear but the drivers bank was very carbon coated. So i had a bud of mine scan the code. It came up as random missfire and low voltage. I drove it for about a week and then one night when i started it up it had zero power. We pulled the o2 sensors and it seemed to have some snot back. I ended up cutting the cats open, pulling out all the ceramics, and welding it back up. The drivers side cat ceramics were black and almost wormholed. The passenger side didnt look half as bad. So the truck runs way better now and has lots of power back, but it is still burning way rich (with the sooty pile) and still the problems with voltage and the miss. I am thinking that the plugged cats were the original problem and now its the fact that im basically not running cats???? I think i should have my bud try to delete the codes and take it from there. Is there any way to bypass the cats per say? Could it be just the o2 sensors? Please any help would be great, as I live way way up north, there is only one gm dealer in town and they are so far behind i cant get my truck into be serviced for min 2 weeks.

Thanks

[2000DV4.8]

I believe there is a 100,000 mile warranty for anything emissions related, but I could be wrong.

[66nova]

Hey im new here so hello to everybody. I have an '05 sierra 4wd with the 5.3l engine. Recently the check engine light came on and the truck was burning very rich with a pile of soot from the tailpipe on the ground. I changed all the plugs and they looked good for wear but the drivers bank was very carbon coated. So i had a bud of mine scan the code. It came up as random missfire and low voltage. I drove it for about a week and then one night when i started it up it had zero power. We pulled the o2 sensors and it seemed to have some snot back. I ended up cutting the cats open, pulling out all the ceramics, and welding it back up. The drivers side cat ceramics were black and almost wormholed. The passenger side didnt look half as bad. So the truck runs way better now and has lots of power back, but it is still burning way rich (with the sooty pile) and still the problems with voltage and the miss. I am thinking that the plugged cats were the original problem and now its the fact that im basically not running cats???? I think i should have my bud try to delete the codes and take it from there. Is there any way to bypass the cats per say? Could it be just the o2 sensors? Please any help would be great, as I live way way up north, there is only one gm dealer in town and they are so far behind i cant get my truck into be serviced for min 2 weeks.

Thanks

 

Yes it could be. How many miles are on your truck? With an 05 I would think O2 sensors before cats.

[Wingnut]

There should be 4 O2 sensors if I'm not mistaken. Two before and two after the cats. You can remove the two after the cats (as long as you fill the holes) and tune out the codes that it'll throw. Also...If you remove the cats, your truck is going to smell GREAT. It'll make your garage smell, your clothes smell, possibly even your hair

 

Seriously though...Removing the cats is illegal and WILL stink to high heaven (I may like the smell, but I don't want it in my clothes).

[BuckFeverZ]

I believe there is a 100,000 mile warranty for anything emissions related, but I could be wrong.

 

For some reason I wanna say the warranty is only 80,000 miles. I could be wrong too

[txab]

I believe there is a 100,000 mile warranty for anything emissions related, but I could be wrong.

 

For some reason I wanna say the warranty is only 80,000 miles. I could be wrong too

 

 

8 years. 80,000 miles.

 

Fix your problem and replace the cats. I'd look strongly at the O2 sensors. While I'm not on the global warming bandwagon, cats serve a very good purpose

[2000DV4.8]

I believe there is a 100,000 mile warranty for anything emissions related, but I could be wrong.

 

For some reason I wanna say the warranty is only 80,000 miles. I could be wrong too

 

 

8 years. 80,000 miles.

 

Fix your problem and replace the cats. I'd look strongly at the O2 sensors. While I'm not on the global warming bandwagon, cats serve a very good purpose

 

 

Exactly. The modern emissions stuff is good enough that removing it won't give you any major benefit, and there's absolutely nothing good about polluting more. Will it be the end of the world? No. Does anybody enjoy smog and acid rain? I know I don't.

[welderdave]

I believe there is a 100,000 mile warranty for anything emissions related, but I could be wrong.

 

For some reason I wanna say the warranty is only 80,000 miles. I could be wrong too

 

 

8 years. 80,000 miles.

 

Fix your problem and replace the cats. I'd look strongly at the O2 sensors. While I'm not on the global warming bandwagon, cats serve a very good purpose

 

 

Exactly. The modern emissions stuff is good enough that removing it won't give you any major benefit, and there's absolutely nothing good about polluting more. Will it be the end of the world? No. Does anybody enjoy smog and acid rain? I know I don't.

 

 

Hey thanks for all the replys. As for the smog control, I live in canada and our laws are different. I can only assume that its because of the population being less. Less vehicles, less smog. Removing the cats is not technically illeagal where i am but frowned apon. This is only a temporary fix as i am moving soon and dont really have the cash to put in 700 bucks worth of cats. If its the o2 sensors why would it run so much better now that the cats have been "unplugged"? What am i looking for on the o2 sensors as far as replacing them goes? Thanks

[2000DV4.8]

Hey thanks for all the replys. As for the smog control, I live in canada and our laws are different. I can only assume that its because of the population being less. Less vehicles, less smog. Removing the cats is not technically illeagal where i am but frowned apon. This is only a temporary fix as i am moving soon and dont really have the cash to put in 700 bucks worth of cats. If its the o2 sensors why would it run so much better now that the cats have been "unplugged"? What am i looking for on the o2 sensors as far as replacing them goes? Thanks

 

Maybe it's because of the exchange rate, but $700 sounds like way too much for cats. You can get Magnaflow universal cats on Summit anywhere from $70 and up, I got a pair waiting to go on that were $100 a piece.

 

(I'm also assuming from your username that you can weld. )

[66nova]

Are both banks blowing black smoke? Again, how many miles are on the truck?

 

My last truck had well over 100,000 miles on it before I replaced the catalytic converter and the only reason I replaced it then was for a high flow converter. And yes an aftermarket cat is much cheaper than a stock replacement.

 

My line of thinking is the original problem was the O2 sensors. A bad oxygen sensor can ruin a cat. But replacing the oxygen sensor without having the converters in place still isn't going to yield good results, the truck will basically think it is cold all the time = Rich.

[Draenor]

I believe there is a 100,000 mile warranty for anything emissions related, but I could be wrong.

 

For some reason I wanna say the warranty is only 80,000 miles. I could be wrong too

 

 

8 years. 80,000 miles.

 

Fix your problem and replace the cats. I'd look strongly at the O2 sensors. While I'm not on the global warming bandwagon, cats serve a very good purpose

 

Not any more. That warranty is toast!

[txab]

Are both banks blowing black smoke? Again, how many miles are on the truck?

 

My last truck had well over 100,000 miles on it before I replaced the catalytic converter and the only reason I replaced it then was for a high flow converter. And yes an aftermarket cat is much cheaper than a stock replacement.

 

My line of thinking is the original problem was the O2 sensors. A bad oxygen sensor can ruin a cat. But replacing the oxygen sensor without having the converters in place still isn't going to yield good results, the truck will basically think it is cold all the time = Rich.

I guess it would run better after removing your plugged cats. But you're still running way TOO RICH. You're probably dumping fuel into your oil. I would also think it would throw codes for catalyst efficiency or inefficiency when it compares the pre-cat O2 sensor readings to the post-cat O2 sensor readings.

 

Welderdave, replace with aftermarket cats. Your engine will appreciate it. Plus we all breathe the same air.

[txab]

I believe there is a 100,000 mile warranty for anything emissions related, but I could be wrong.

 

For some reason I wanna say the warranty is only 80,000 miles. I could be wrong too

 

 

8 years. 80,000 miles.

 

Fix your problem and replace the cats. I'd look strongly at the O2 sensors. While I'm not on the global warming bandwagon, cats serve a very good purpose

 

Not any more. That warranty is toast!

 

 

 

After farking with the cats it is......

[Draenor]

Are both banks blowing black smoke? Again, how many miles are on the truck?

 

My last truck had well over 100,000 miles on it before I replaced the catalytic converter and the only reason I replaced it then was for a high flow converter. And yes an aftermarket cat is much cheaper than a stock replacement.

 

My line of thinking is the original problem was the O2 sensors. A bad oxygen sensor can ruin a cat. But replacing the oxygen sensor without having the converters in place still isn't going to yield good results, the truck will basically think it is cold all the time = Rich.

I guess it would run better after removing your plugged cats. But you're still running way TOO RICH. You're probably dumping fuel into your oil. I would also think it would throw codes for catalyst efficiency or inefficiency when it compares the pre-cat O2 sensor readings to the post-cat O2 sensor readings.

 

Welderdave, replace with aftermarket cats. Your engine will appreciate it. Plus we all breathe the same air.

 

+1

 

Your running the risk of damaging your bearings.

[welderdave]

Ok, so here is where i got today. Yes the cats i priced are an oem replacement for the crappy parts store way up here in northern canada. They couldnt find tits in a strip joint!! My bud and i had another look today. Codes came up as p0131, p0300, p0171. Now, im no mechanic by any means, so I cant remember what the codes were other than the right bank is burning to lean. But the truck seems like its burning too rich??? We tested for leaks at the intake manifold, we tested vaccum preassure on the pcv as well as the egr, they were both good. We are goin to talk with another mechanic bud who works at the gm dealer. So i will get back here tomorrow night. Thanks