I have a 98 prelude when i bought the car the cat was completely bad. when i pulled it from the car the the honeycomb inside as broken into peaces i bought a cat for a guy that flipped is 2001 prelude. the cat had be replace with an oem cat less then a year before i bought it. i installed in in my car and the cel went away. after haven it on the car for about 6 months the cel came back on throwing code p0420. i haven't pulled the cat off yet but i am going to today. my question for HT is what would cause the cat to go bad quickly? any help would be great thanks in advance.

 

does your car burn oil?

 

Also, do you drive the car only short distances. If the cat doesn't warm up fully before you shut it off, it basically sits "wet" with gas (also there is a lot of ethanol in our gas out west which can compound this problem)

 

Sounds like the cat you bought 'used' was a little older than the guy told you it was.
You can get a brand new cat $50 shipped

 

i know that it leaks so i dont know how i would tell if its burning it too

he had receipts for the cat.

i use it for commuting back and fourth to work witch is about 35miles one way

 

cheap high flow cats are the way to go.. mine was $50 and $80 to weld the flanges on it w/install.. been doing strong for a year now

 

Try changing your o2 sensors. The only way your car knows the cat isn't working is by comparing the o2 sensor readings; if they're bad it could throw a code. The other common cause is an exhaust leak causing the code to trip.

 

There's a difference between a good cat and a cheap one, not just the price, the catalyst is a precious metal, you think if they packed it with the same amount as an OEM cat they could sell it for a fraction of the price? Hell no, the company manufacturing them would be losing a LOT of money.

 

not what I've heard

^i agree with this guy

i have a spear downstream o2 sensor in the garage i will try to put on tonight. but if it was the o2 sensor wouldn't it through a different code i know there are codes specific to the o2 sensor.

 

im just telling you what has worked for me so far......

 

I bought one off of Amazon for 48 dollars. It is great for passing smog, improved on mpg. After couple of months, cheap stuff start to show its face. You will see your mpg will go down, car seem to be choking once in a while. Although mine passed smog after two years now, but mpg isn't great at all. Save money and get a decent one at least, it good for long run...

 

Thanks for the input. I not wanting to buy a cat again I'm going to change the downstream o2 sensor if that doesn't work I'm just going to buy a test pipe and try the sparkplug defowler trick.

 

That will work fine as long as you don't have to worry about passing a smog test.

 

I don't have to worrie about that until next year. And when that time comes I might just work my way around it.