2002 Silverado 5.3L Catalytic convrt

[Gito]

Engine light has been going on and off for a few months now on my 2002 chevy silverado 5.3L with 195,000.
P-430 Catalyst System Efficiency, Below threshold(bank 2) and
P-300 Random Misfire Detected

It sure looks like my Catalytic Converter is gone. I was first thinking about changing 2 oxygen sensors on the right side that have never been replaced. Will changing the Oxygen sensors fix my troubles or are my Cats toast. If my Cats are toast I want to make sure to get good replacements and not junk. Who makes good Cat converters and where is the place to purchase them. Im in Southern California so passing Smog is a must. My DMV registration is up in November...please advise

 

[Highline9]

Get a cat that looks like oem or it won't pass the visual inspection. Try a bottle of redline fuel system cleaner first.

 

[Chris142]

as long as the replacement cat is carb approved its a legal replacement . p0420 codes are 99% of the the time a bad cat. gotta figure out the missfires too. as that will cause it to fail the test also

 

[bama7x57]

I would focus on the P-300 Random Misfire Detected. Good chance it's setting off the the other code.
My 5.3s don't run good unless I use AC Delco plugs and wires and a random misfire is usually plugs, wires or coils. I'm still running my original coils with over 250K miles.
EBAY has the best deals on AC DELCO wires for the 5.3.

 

[GMBoy]

Yes, that dreaded code is 99% a bad converter. But even more importantly - you need to address the misfire as that is probably what killed the converter. Fix that issue or you will be buying another converter down the line.

 

[Gito]

I replaced the spark plugs with iridium 2 years ago and replaced the wires also. I replaced the O2 sensors on the drivers side but not the passenger side. How do I check for a bad coil and which type of coil(s) are good. If the cat is bad who or which manufacture makes good ones where I would be able to just swap out without having to weld? And how do I figure out which Cat is the bad one?

 

[crazy8]

Due to the fact that you have multiple codes I would recommend a professional shop for a complete diagnosis and a compression/leak down test. Iridium plugs should not be a problem, but I am seeing some GM v-8's with valve seat problems, that may be the cause of your ramdom mis-fire codes, if you had a hard mis-fire in any one cylinder you would have a code for that cylinder. If you need a cat. I highly recommend a Walker direct fit or 2nd choice a Magna-Flow direct fit as a OE cat is probably not available. Good luck.

 

[GMBoy]

2000-04 models had intake leak issues and there are 3 bulletins out on it. Test it by spraying carb cleaner along the intake manifold where the gasket is. If RPM changes..you've found your leak. Torque the bolts and see if it goes away..if not..replacement is cheap and easy. If it is leaking, it will be on the pass side..also check PCV pipes.

Your coils are ok more than likely because you have a P0300 code not a specific cylinder code.

Your code says BANK 2, that is the passenger side.


I've bought from here before and have been very happy. For $254 you get the whole Y-pipe with convertor!

http://www.discountcatalyticconverters.com/shop/?N=0&VN=4294967119+4294965721+4294965422+4294967156+4294966706&Nr=AND(part:Catalytic+Converter)&events=partfinder

 

[crazy8]

Good idea about the intake leaks, he has to buy a Calif approved cat, not sure your source will work.

 

[Gito]

So if my Cat Converters are bad, how do I figure out which one is bad?..Correct me if I'm wrong, I see 2 Cats under the truck. I looked up the Magna Flow Cats and they are OK in CA. The price is pretty high for 1 direct fit Cat Converter...Am I looking at the right part or is this price for 2 Catalytic Converters?
http://www.summitracing.com/parts/MPE-93419/

 

[Gito]

Woops, Magna Flow Catalytic Converters say they are 49 state ok but exclude CA...Let me continue to look into this but if someone beats me to the info on where to get a good direct fit Cat please advise

 

[Gito]

I think I found the CA legal Magna flow Catalytic Converter part#458062

http://www.magnaflow.com/02catalytic_con...irectfit=458062

I will give them a call to confirm

 

[crazy8]

Walker direct fit should be Ca legal, but please solve all of the engine codes before you replace the cat.

 

[Gito]

Thanks, I will start with the misfiring codes

 

[mechtech2]

Sure, it can be a converter, of course.
But that misfire could also cause it as a secondary problem.
So would a bad O2 sensor in front or behind the cat.

 

[dailydriver]

Originally Posted By: crazy8
Good idea about the intake leaks, he has to buy a Calif approved cat, not sure your source will work.


I believe Eastern Catalytic makes the CARB approved catcons for that truck/engine (and they will be the closest in longevity to the actual OEMs/originals out of all of the aftermarket replacements).

I know that neither Magnaflow, nor Walker make CARB versions for my car with a very similar engine as his truck (at least they did not when I was looking for one a couple of years ago, YES, sadly enough, Joisie required/got CARB catconed cars

).