BigDaddyO

OK here is the deal, i recently purchased a 99 K1500 burb used off craigslist.
Today during lunch I get a service engine soon light and stopped into autozone. codes show that the Catalytic converters are shot.
It has always idled a little rough so that might be caused by a plugged cat right?

long story short, i'm broke and have no real recourse besides idle threats.

"Since i'm not sure of the legality here, lets just call this a theoretical discussion"

Can I GUT the catalytic converter? Remove it, stab a pipe through it and re-attach? will this mess with the O2 sensors? Will the SES light go off after a while of driving it gutted? any other thoughts for a really cheap way of getting past this? Will it pass inspection in New York after gutting?

I have a cheap-o HF welder so welding is not a problem

Thanks

in2pro

Yes it will mess with the O2 sensors and the SES light will aways be on, the lack of back pressure will most likely cause it to run like crap and could also burn valves.. it will never pass tail pipe inspection without cats in place...

You may want to check for cats at a junk yard they may get you a few more miles and there should be some affordable after-market cats that should work...

tbone510

Sounds like the same exact thing that is happening with mine. 99 K1500 suburban. today the SES light went on and I knew it wasn't due to the fuel cap being loose or anything like that. mine idles a TINY bit rough but it's nothing major, I'm wondering if I have the same problem as you...

LARIDERS

you can get some cheap after market (hi-flow) conveters. I think I have seen them for $50 a pop. I had some one time and they never pulled any codes.

73shark

Not sure a clogged cat would cause a rough idle. I do know that one will kill power. Does it just have one cat or are there one on each back near the heads?

BigDaddyO

I was a little shocked when I saw your post about $50.00, we had to replace the converter in my wifes corolla a few years ago and it was almost $900.

I found a Universal fit catalytic converter from JCwhitney for $89 i could swing that. Do the Suburbans have 1 or 2? Do i need to replace the O2 Sensors also, i hope not? what else would i need for this?
http://www.jcwhitney.com/universal-c...821d317y1999j1

Thanks a bunch. i feel a whole lot better now. shouldn't be anymore work to install the universal fit than it would have been to remove and gut the current Cat.

BigDaddyO

Yeah, I would say TINY bit rough as well for mine, it's not going to stall or anything like that. If you get your codes and your cat fixed before me, let me know if it fixes your idle issue. I'll update this as well when I get mine done. Granted, it will probably be a while since i don't have too much time between work and kids.

in2pro

I would do a bit more troubleshooting before shot gunning the cats, and your were correct to fret the cost as GM parts direct list the cats for the 99 5.7L as list $1200 and sell for $900....

BigDaddyO

OK, i dug out the printout that autozone gave me.

Definition
Catalyst efficiency low-bank 2

Explanation
The oxygen sensor monitors the Catalytic converters ability to store oxygen

Probable causes
1. Catalytic converter defective (failure possibly due to #2,3, or 4)
2. Engine misfire or running condition
3. Large vacuum leak
4. Engine oil leakage into exhaust-valve guide seals, piston rings


i'm pretty sure it's not #2 since there have been no misfires and it runs fine.
How would I check for #3? are there other things that would have problem with a vacuum leak?
How would I check for #4?

Thanks

73shark

A vacuum gauge can help detect vacuum leaks. Also can use an unlit propane torch and play it around suspect areas. If there is a vacuum leak, the idle speed will change when the propane is sucked in.

Bad valve seals will usually allow a puff of blue smoke on start-up after an overnite soak. Oil consumption can be monitored to determine if oil is getting burned by getting past the rings. Also can do a compression and leak-down tests.