Advice on a 1996 Cat Issue
 

My CEL came on last night, took it to Autozone after work today and they said it's the catalytic converter. From what I've read so far in other posts, off-brand cats will only work for a short period of time, and an OEM will cost about as much as the car's KBB value ($1,200-1,500). I haven't had many problems with this car since I bought it at 83K miles, but now it has about 135K miles, and I'm not sure I want to risk putting that much money into a car that is probably just going to run into more and more problems in the near future. I already replaced the 02 sensors and control arms (which I hear are common problems), but other than that I've avoided any other major repairs. I don't live in an area that has emissions checks, and the car runs fine as far as I can tell. I never would have suspected anything if the CEL didn't come on. What would you suggest I do? If I know I can get ~50K more miles out of this after replacing the cat, I'd do it in a heartbeat, it's just so risky with the possibility of so many other things going wrong. And most importantly, how long can I safely drive around with this issue? I may have to start looking for a new car, but I'll need to get around in the meantime.

Advice on Cat CEL Issue
 

I would first try replacing the downstream oxygen sensor before purchasing
a new catalytic converter. I am assuming here that the trouble code which
Autozone found was an off normal reading from the downstream oxygen
sensor.

I'm going back tomorrow to get the exact error code so I have a better idea what I'm dealing with.

my experience with aftermarket cats failing 'early' is related to the following issues, many times both.

the cat is a cheapy 'universal fit' that is too small and fits every car a little bit.

underlying issues of poor driveability/engine performance are not addressed to correct the issue at hand that killed the cat in the first place.

most emissions repair shops can actually test the cat for oth efficientcy as well as oxygen retention. both of which are factors in grading the performance of the cat.

the rear o2 sensor should also be checked to verify proper operation.

it's sole purpose is to monitor the cat, and will not affect anything with the way the car drives. it will also not kill the cat.

i have a 'non oe' cat on my e36 and have no issues with performace or emissions. (in fact it was for a ford....)

stick with reputable catalytic converters and you should be fine.




df

I had failed original cats in two of my 318's, a ti(180k mi) and an ic(160k mi). Failed SMOG checks in both cars as a gross polluter. Swapped out both cats with Magnaflow 36004, which is CARB compliant/required here in California. Both cars passed the SMOG test cleanly afterwards. First install was just under $215, second one was $180.

I look for the cats to pass two inspections which are two years apart. If they last longer, great!

Good luck! :cool:

Thanks for the advice everyone. A few days after my original post, the weather warmed up and my CEL went off for a day or two before coming back on so I took it back in to get the exact code, which was the p0420 catalytic efficiency code. I got some fuel injector cleaner and had them clear the code to see how long it takes to come back.

The only change in performance I've noticed is a slight drop in MPG of about a mile or two, but I'm not entirely sure that it's not due to switching to my winter tires. Assuming that the cat is the problem, since I don't have emissions checks here in MI, is it safe to not worry about this or will it be detrimental to my car's overall well being?