VA1991Z28

iTrader: (1)

Well I took the Camaro to get emission tested and guess what, it failed. Here are the numbers:

15 MPH
Limit --- Reading --- Result
HC ppm: 0055 ...... 78 ........... FAIL
CO % : 00.22 .... 0.25 ........ FAIL
NO ppm: 0720 ..... 516 ....... PASS

25 MPH
Limit --- Reading --- Result
HC ppm: 0060 ...... 69 ........... FAIL
CO %: 00.32 .... 0.32 ........ PASS
NO ppm: 0700 ..... 412 ....... PASS

So I had them hook it up to the computer to see if it could help figure out why and everything came back clean, no codes and all the sensors working. Finally they did a "Delta" Test - put the car under load and then measure the temperature of the cat inlet and outlet and there should be @100 degree difference. Well one side is ok, but the inner cat there was no difference. (I've never heard of this test, is it valid?)
These cats are exactly 2 years old!! I bought the car-sound 23479 2 1/2 mandrel bent stainless steel Y-pipe with 2 car-sound high flow cats and have this hooked to a Banks Stinger exhaust. After getting this exhaust done and completing my fuel injector replacement (SVO #19lb) - the car passed emissions with flying colors, but was just 2 years ago.

The reason for the car-sound cats was to replace the Random Technologies Cats that I paid to have welded into the stock Y-pipe after the originals failed/clogged. The Random Cats lasted less than two years. So I spent several months rebuilding the intake system (new fuel injectors, senors, cleaning the plenum, AFPR, new gaskets, plugs, wires, caps, timing, etc..) and now another set of cats is toast. Any body else having issues with cats burning up / breaking up? I need the cats since I have to pass emissions on the treadmill test, any suggestions? I called car-sound but they will not help since I bought the cats more than 2 years ago (but they have only been on the car for two years - but they say it is 2 years from date of purchase). So I can't say anything good about car-sound and they won't stand behind their products. The car is not throwing any codes and is getting 19 MPG in mostly stop & go traffic. What could be causing the cats to keep burning up?
I'm just frustrated and this is getting way too expensive to do ever two years. Should I get different cats and have those welded in place of the car-sound cats? Which high-flow cats have held up? I wasn't planning on doing headers and I wanted to keep the stock config of two cats on the car, any suggestions?

Thanks,
VA1991Z28

Kevin91Z

iTrader: (1)

The biggest problem with cats breaking up is the engine running too rich or too lean. But you said you have replaced the injectors with new ones, so I cant believe that's it. However, you have had two different cats from two different companies both die on you, so that's gotta be what it is. Have you ever used a wide-band O2 sensor on the car? How about some kind of scan tool to see what the regular O2 sensor is doing? You could be driving around with the fuel trims (called the BLM and INT) maxed out too rich or too lean and not even know it. I have the same dual Magnaflow (car-sound) cats on my car for more than two years with no problems. However the first time I put a new engine in the car without tuning, I had a cat fail and break apart on it, because it was too rich.

VA1991Z28

iTrader: (1)

Kevin91Z,

Thanks for the reply. Can you give me some more info about what kind of scan tool to look for (hopefully one that doesn't break the bank) and what to look for? I guess I need a quick "Scanning for Dummies". What do you use? I haven't used a scan tool on the car. The O2 sensor has about 28K on it, BUT I had it replaced (it threw a code) while getting other work done to the car, the dealership stripped the threads so I had them helicoil / weld it in, so I'm not sure what to do with it now. I guess I could leave that one and relocate/tap a new one a little lower? Can it be retapped? They didn't want to do it, they wanted to sell me a new exhaust manifold, so I had them heli-coil it in. What do you think?

Also I have been chasing a ping in the engine under moderate load, not WOT. The plugs/wires/dist cap/ rotor are 7 months old and the timing is set at 6 degrees. I sprayed starter fluid around the plenum to check for a vacuum leak, but nothing. Maybe the EGR (its the original)? Could the pinging (maybe lean mixture) cause the cat to burn up?

I did replace the water pump since the new cats went on and with it, new hoses and 180 degree high flow thremostat.

What would you do in my situation (as far as the cats go)? Pull down the 2 yr old Y-pipe and weld in replacement cats (so new cats & labor) or just replace with a new Y-pipe with the cats ($378 from Summit + labor)? I know I need to figure out what is causing this, but I'm also under the gun to get the car through emissions before my registration expires.

Any ideas at this point would be helpful.
Thanks.