Hi all,

First-time poster here. I've got a 98 Accord V6 EX with 190K miles. Recently got a check engine light and a P0420 code. Then the car started bogging at around 60-70mph--speed would just drop and I'd have to step back down on the accelerator to bring it back up. Dealer looked at it, took off the cat and its got metal bits rattling around inside.

I replaced the catalytic converter back in 2009, and it went bad again in 2010 so I replaced it with the current one, that has now gone bad. Both were Magnaflows. I'm trying to figure out why they keep failing. Dealer recommends a valve adjustment. I'm thinking of putting on a Walker cat because the Honda cat is just too expensive and I've heard they are not much different. I really think the problem must be further upstream with the engine. Any ideas on what could be causing the cat to fail so much? Is this just common? Is a valve adjustment necessary?

Thanks!
James

 

Are the valves making noise? How are the other maintenance items like the spark plugs? Does your car have a distributor cap and rotor?

 

Hadn't noticed any noise. Mechanic said the valves could be too tight. He did say the spark plugs were dirty with some kind of build up on them. Not sure about distributor cap and rotor. My car is stock. Thanks!

 

I think I have the same problem. i have a 98 LX with almost 300k on the original engine. I thought the transmission was slipping but not so sure after today. I was getting on the freeway and at 50 mph it stopped accelerating. I had to ease off the gas and then when I accelerated again everything was fine but the check engine light started flashing on and off until I got home. When the car was started back up, it just stayed solid. I also thought it smelled funny, but not sure. However, I had noticed yesterday that it was smelling really gassy.

Any thoughts would be appreciated. Thanks.

 

metal in ur cat... not sure what there isnt to understand?
1- a cat is like a honey comb.. there shouldnt be "metal" in there
2- depending on your exhaust, backpressure can make a cat fail prematurely

 

That "honey comb" is the metal......some expensive metals at that, hence the cost and why people steal them and if you recycle it you can get some money for the old one (~$100 ?).

Many reasons they fail, the most common is a rich running engine. So tune up items must be up to date, old/bad/lazy O2 sensors should be replaced.

A flashing CEL as you drive is a very bad thing. You need to have the codes addressed ASAP.

 

dude if the cat rattles, and the old one rattles, its a physical failure theres nothing wrong with your car.

 

The question is why have a couple of em failed quickly. I'd be asking the same thing & not simply buying more catalytic convers.

 

Thanks for the help. Obviously with the cat being shot it had to be replaced, but what was causing it to burn out prematurely? Honda mechanic put in a new Walker cat and it was heating up pretty bad...800+ degrees. So he did a valve adj.--they were really tight, less than 2000th/inch. Front O2 was also in bad shape, had some oil on it. So replaced that with a Honda one. Oh, and put in new spark plugs. Cat is not as hot now, more in the 600 deg. range. Hopefully the new 02 sensor will regulate the fuel/air mix better. I'll be keeping an eye on it.

 

Many companies will deny warranty claims on cats unless there is documented proof that tune up items, O2 readings and a few other odd things are supplied or were replaced when the cat was....or they just jack up the cost of the part to cover claims.