ack4007

I have to hang my head in shame...I think that I have blitzed my the cats using fuel system cleaner. Not only on one Boxster but two.

I am curious if y'all believe my theory is correct.

Here's the background. I purchased my first Boxster (2001 S) in January with 58K. Along with changing the oil & filters, I ran some STP injector cleaner through one tank of fuel. Within a week there was a rattling from the back tied to acceleration. It was a pain to isolate, but I finally pinned the noise to the right side main cat connected to the header.

I chalked that up to bad luck and lived with the embarrassing noise. The sound ceased one wet day in April when a friend (really it was a friend) wrapped the car around a tree.

Two weeks ago, I replaced the car with another '01 S with 65K. (M030, Litronics, new canvas with glass, Sport Classic wheels, and oem sport exhaust - Actually, I'm quite pleased with the upgrade over the dead one.) In ritualistic fashion, I changed the oil & filters and ran some FI cleaner.

Well...after a week I can hear that tell-tale rattle for the first time. It resonates dramatically through the sport exhaust under acceleration. The coincidence is too painful for words. I can only guess that the FI cleaner has cooked the fragile cat. Even the the housing is discolored to a slight pink that wasn't there during the PPI.

What do you think? Am I just unlucky or did I screw up? More importantly, what are some good excuses to tell my wife why I need to throw in several hundred $ for a replacement?

Macster

Sometimes a coincidence is just a coincidence.

Get a new theory, maybe. The extra discoloration may be a sign you overcooked the cat or it may just arise because the hotter portion of the failed converter is now touching the outer housing metal.

Unless you overdosed the car on FI cleaner, used some goofy cleaner that you spray in the intake and let the engine sit and soak or in anyway caused raw fuel or cleaner to be fed to the converters, they failed because they were worn out or more likely based on what you wrote they suffered from some physical/mechanical failure.

Tell you wife you love her with all your heart every chance you get and one evening or two not too close together, offer to clear the dinner table, do the dishes while she's free to hit the couch and put her feet up.

Or treat her to a spa day or weekend at a local spa.

Be aware she'll check your collar for blonde hairs, so do not go near any Russian Wolfhounds.

Oh, let me know where you can buy a replacement converter for a couple of hundred dollars. Factory items cost around $1000. Used ones are probably the duplicates of the ones you have now.

Better make that spa thing a week long thing... and do the dishes every night the rest of your life.

Sincerely,

Macster.

ack4007

Thanks Macster.

It's good to know that bad luck may have had more to do with the trouble than bad car care. The FI cleaner was a one shot bottle that I put in during a fill-up. From what I have read, it's probably useless.

As for the cheap replacement, I plan on deleting the cats just out of spite for them by installing after-market headers with 2 O2 sensor ports and spacers. I live in a rural area with no emissions regulations. My independent says that I am too sensitive about the noise, but likes the idea of a more streamlined exhaust.

Spa experience is a good idea. It's a shame that I already have dish duty for the rest of my life due to prior circumstances.

Thanks again, AK

Macster

I'm very very skeptical a converter delete with the result the #2 sensors will not have true converter processed exhaust gases blowing past will fool the DME for long.

Emissions compliance, on-going and long term is very critical to an automaker.

First the automaker is on the hook for any major emissions hardware failure. Converters due to the their expense are at the top of the list of things the automaker seeks to keep healthy and to at the first sign of any trouble, flag a problem.

This is why during a misfire the CEL can flash. This is telling the driver the car's converters are at risk of serious harm.

Next, the EPA continuously sources older used vehicles and tests them for compliance. If it was found an automaker's products were performing below par...

Thus automakers put a lot of time and money into monitoring the performance of the converters to ensure compliance long after the emissions hardware warranty is expired.

The DME looks at the voltage levels of the #2 sensors and expects to see a pattern that in some way follows the up and down voltage swings of the #1 sensors.

The DME will adjust fueling to try to get the voltage behavior it wants, expects. This can result in sub-par fueling and eventually a check engine light.

In the meantime not only is the engine 'dirty', it burns more fuel, and is subject to an increase combustion chamber deposit build up with only makes things worse. This might result in a higher level of fuel contamination of the oil.

Or the DME cuts back on fuel and the engine runs lean and hotter and driveability suffers. The engine is more powerfull. better running only in your mind.

Really, it makes for the best car experience for you -- and your fellow man -- to keep the emissions system intact and in good operating order.

Sincerely,

Macster.

ack4007

Thanks for the further insights Macster. I was under the impression that the delete would mimic RoW set-ups and hadn't considered how the US DME would deal with the subterfuge along with the knock-on effects. Reprogramming the DME to deal with the delete would be more trouble than just sticking with OEM headers.

What's the consensus on running with rattly cats? Have many others around here suffered this problem?

Right now, the noise rates as 'annoying.' The exhaust needs to be hot and the throttle needs aggressive action to make the noise. Is there a point when I should be worried about sending scrap metal into the secondary cats causing even more damage?

Thanks again. AK

lee101315

I installed a set of ebay headers, bypass pipes, and an NHP muffler without swapping the DME setting to ROW ( which I will do in the future to get rid of my CEL ).

By far, it was the best modification I performed on the car...aside from installing a 3.4 engine

I immediately noticed that the car required less throttle to maintain a cruising speed, and Engine temps dropped a few degrees as well. The design of the primary cat is not for performance, it is designed to get to operating temperature in under 2 minutes...so the car is much happier without them.