Cat insufficiency
 

I keep getting check engine light with code for bank 1 cat insufficiency. Anyone know of a good source for some low mileage used OEM replacements? My Indy mechanic says it can't be anything but the cats-car runs fine

Bone yard item; try Woody.

I got a header cat replacement several months ago on eBay for about $260.

I would also try Woody first (Itsnotanova) as he is an honorable gentleman that can be trusted on this forum and has more than fair prices.

My old cat has lost the cement seal between the cat element and the shell allowing gasses by. You can hear it slide back and forth inside once its removed from the car.

Its an easy repair that does not tale long. Don't forget to order a header and pipe gasket for either end if you DIY.

I have a pair of very low mileage cats from a 2002 S model. PM for price and pics. Actually still have the full exhaust system.

I have seen what seem to be direct replacement parts on eBay but I don't recognize the brand names, which one did you get? Are they smog legal for CA?

Out of curiosity, what did this sound like when running the engine before you fixed it?

I have a metallic rattle noise that only happens in certain RPMs when the engine is warmed up, coming from one side of the engine (passenger side), it sounds like up near the engine somewhere. It sounds just like a rattling heat shield but I've checked the obvious heat shields and for exhaust component contacts with frame, etc, and so far can't locate the source of the rattling noise.

I have no check engine light problem nor performance problems (at least that I've been able to notice - car has been like this for about a bit over the year since I've bought it, and it's my first boxster.) 2001 base 2.7. Thanks!

The heat shield that surrounds the pipe often rattles on the pipe itself. Attacking with a big pair of sliplock pliers or even a BFH can remedy the problem.

Thanks for the suggestion. I already fiddled with the mid-pipe formed-over heatshield, which after I banged my hand against (from underneath the the car, with the engine turned off), I heard some rattling pebbles from inside - stuck between the formed heat shield and the mid-pipe exhaust tubing. I pried the heat shield halves apart enough to get the pebbles out, and was excited initially when I could bang on the pipes and heard nothing (but silence), but then after driving the car, was disappointed to find the exact same rattling noise (after engine being warmed up) was still happening as before. So apparently this wasn't the problem!

After that, I did get my wife to duplicate the rattling noise while I had the car up on jack stands and probing underneath to generally locate the noise. I determined it seemed to be coming from up near the engine, almost seemingly up high on the passengers side. But I can't help but think it still may be something loose in the guts of the passengers side primary cat? (That only rattles after its expanded a bit from being warmed up?) Or maybe something inside the engine, but it's definitely a metallic rattle that sounds just like a heat shield.

First things I checked were the heat shields covering the secondary cats, and the one protecting the transmission shift selector. And then I moved onto those formed heat shields over the mid pipes. So far, no easy fix to the rattling noise.

I just got a used OEM Header/Cat from a 2002 (45K miles) Boxster.

There is a new Universal CAT that you can get welded in, but it would be quite a welding chore to do properly and a Jig would be needed to ensure everything aligns properly.

Much more effective to just buy a used one as they will outlast the car unless there is physical damage or the cement holding the element in place breaks free, (From an impact I would think).

A brand new replacement is around $1800.

Surprisingly, in my case I did not hear any rattle from my faulty CAT.

I have read that the rattling could be due to the need of a new engine mount rubber as the play in a worn one seems to cause pipe rattles as the engine moves around excessively.

Thanks for the info on your failing cat not making noise - the data point is much appreciated. I already replaced the front engine mount, and it gave no fix for the rattle. I wonder if the rattling could be from a clutch or DMF that's on its way out? I'm going to be servicing the clutch fairly soon anyway (as it has a bit of judder/chatter), so maybe I'll learn something more about the rattle then. It will also be a good opportunity to drop the exhaust and give it a good inspection.