Last time I posted here it was about my cats, they had started to crumble, I had new ones ordered and installed for plenty of money.

Today I had the EXACT SAME PROBLEM as last year, first the racket from the exhaust, then it was clogged, the bloody cats are crumbling again I am sure of it!!!

Jesus Christ, what is going on? Why is my car killing cats like this? Is it because of the diverter valve which is stuck and keeps sending air to the cats and never to the manifolds? My mechanic told me it wasn't a big deal and wouldn't hurt the cats!

Well **** if I am going to be paying for this...

If I have to get new cats I will make it so that they can be screwed on, then I will only put them on when I am taking the car to the inspection, my friend does this and his cats are over 10 years old without problems.

Bloody hell!

 

According to my Haynes manual, the air pump is only supposed to pump air to the manifolds and or cat when the motor is cold to help warm up the cat and to help burn any left over fuel from the rich cold-start fuel curve, after that it is supposed to pump the air back into the air cleaner. If the pump continually puts air into the cat it will create high temps in the cat and cook it. The stuck air valve may be your problem.

At least its worth looking into, weather Haynes is wright or wrong.

 

HEAT kills the ceramic cat "bricks." That can be the air pump acting funny, running real lean (high EGTs), spark advance too far retarded (high EGTs again) or having a miss that is dumping unburnt fuel into the exhaust and igniting directly inside the cat.

I'm sure there's other reasons, but that's what I've seem kill 'em from my experience.

Cats don't usually jsut die (unless they're defective). They are MURDERED. Find out why and fix it.

 

Cats are good for a real long time unless the car is not running right. Running real fat will kill them or if the AIR system is not acting as it should and always on ect. You can litterally wear out the car before the cats die.

 

Well I had the mechanics cut it up and see what was wrong, the cats are intact.
So I took it home and inserted a long steel wire and shoved it right up the *** of the car and started messing around and hitting it with hammers, then I pushed the throttle and a whole ****ing load of ceramics came exploding out in large and small pieces all over the ground, these things where leftovers from the previous cats that broke down, for some reason they have not started making trouble until recently.

I repeated this procedure a few times and more **** came flying out, I don't think there anymore there, but if it happens again....

 

When was the last time you had a tune up? Have you replaced the O2 recently? Any exaust leaks around the manifolds/headers/O2 area?

Its possible for the airpump to ruin the cats if theres alot of fuel present on startup. More likely is that the car is just running rich and dumping excess fuel into the cats. With the extra air from the pump, all that fuel burns and dumps an s-load of heat into the cat, which melts it.