lt4 fd

Well its a month after having them installed and what do you know... the reason I had them installed was because before when I originally had the system made they blew out as well, since I replaced the maf sensor since it was throwing a code and put an AIR system back on of my own making, well the plumbing was of my own making. I thought that would have cured it but nay they are rattling again now. Anyone have any idea on what sensors to check or really anything to check that might be causing it? BTW no codes besides an occasional EGR malfunction come on...

OBE1 95Z28

Running rich destroys cats; check your O2 sensors.

Alvin@pcmforless.com

Yep,

Put the car on a scanner. It should never burn up a cat.

lt4 fd

Well I have datamaster and its not saying anything is wrong besides the egr valve and previously the maf sensor. My car has just under 90k on it so maybe ill replace the o2 sensors with the plugs, wires, coil and header gaskets... I really dont know what to think now, I sure as hell am not going to install some more and see if it worked thats way too damn expensive and Ive already wasted hundreds on them... BTW is there a special way to check o2 sensors? Im pretty much going to have to get my cat's made to be removable next year for inspection and wait for these bastards to blow totally out and stop rattling. BTW in open loop doesnt the motor run rich... why wouldnt that blow them out, is that waht the AIR system prevents? BTW I do have an AIR system.

Silver

rattling after a month? i can't imagine a rich engine making them fall apart that soon. i could be wrong. dang. are you sure you didn't hit something with them? maybe the installer is beating them around? strange.

lt4 fd

BOTH times I have had them installed this happened, the first time one started rattling about 4 days after adn the next 3 weeks so I had them both replaced and now about a month after one or maybe both are rattling and it seems like the passenger which is the one that went first last time... but dont trust that just yet I havent looked... Also they hang low but I dont remember nailing anything with them, how hard to you have to hit something to make them break apart and wouldnt they start rattling immediately after you hit something with them that hard?

BTW both times they were ebayed carsound magnaflow high flow 3" cats with no air fitting.

EDS Z28

Yep, this is correct.

I tried running in open loop a few years back to smooth out the idle. I had a nice idle and low end throttle response but the cat didn't last more than 2-3 years.

If you run cats, the motor has to run at or near stoicometric 14.7:1 most of the time. The computer actually makes it run slightly richer and leaner around 14.7 to be really effective.

If you could install a true air-fuel sensor, this would help. I heard the innovate model is great. You could tell while your driving the car whether your rich or lean. They cost aound $350 from www.summitracing.com

Cats are a good thing. Without them the air we breath would be intolerable.

lt4 fd

Thanks for the advice, guys.

Silver

I don't think you'd have to hit them very hard and if you broke them, it could be later until they wiggled loose and started to move around in the casing. Maybe you got shafted by an ebay seller? Maybe the fact that you were able to find the same cats on ebay twice for a reason... hmm.

I dunno. It's just mighty strange that your cats just fall apart. I can't imagine exhaust doing that at any fuel ratio.

lt4 fd

well I did smack one the other day but it wouldnt have been the passenger side it would have been the drivers since it hangs lower.... so not so sure whacking them did it and its a magnaflow cat that is sold by the same ebayer and has hundreds for sale on ebay all the time...

lt4 fd

BTW I passed emissions as well...