42 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHmy cats are kicking the bucket
Leading reported evidence
Replace cats
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I replaced my cats with MagnaFlow units bought from Summit Racing.
Leading evidence: 'Replace cats' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check not tailpipe' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Replace four o2 sensors .code now gone since last summer
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
This time changed all four o2 sensors .code now gone since last summer.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
I will keep an eye out for used cat's on local ads with lower miles.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I've used a lot of CRC products in the past, and unless some of the Porsche gurus say otherwise, that's probably what I use over the seaform on the throttle body.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
42 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
2 acknowledgements have no verified action link; they do not establish a repair result.
Throwing a CEL for low efficiency on bank 2. I reset it a couple of times and it comes back, my car uses zero oil between changes so not contamination etc
I think at 112k miles they are toast.
What are my options? Should I bother with changing the O2 sensors? I have a borescope so maybe I should snake it in and look at the condition of them inside?
I'm in California so have to pass smog in a few months, I don't want to pay $$$ for OEM. I will keep an eye out for used cat's on local ads with lower miles.
I also considered cutting the cans open and welding in some new universal cat elements, anyone done this? I have a 2000 996.1 all stock.
Most likely not the O2 sensors (which have their own codes). Your best bets are:
- A used unit (search for "porsche 996 downpipe" for 3.4
- 200-cell sport cat inserts from Carnewal (ship your cats there for the surgery)
- CA approved direct fit aftermarket cats
I've been having the same problem. My remedy?... lots of "cat food". hahaha Yep, I been feeding it two cans of seafoam, and the CEL went away. If this doesn't work in the long run, I may have to replace the catalytic converters, but I'm hoping to wake up my dead cat! Those darn cat converters are crazy expensive!
Try swapping the downstream O2 sensors from one site to the next. If the code follows the sensor you have your answer. If it doesn't, you'll have you answer too.
I'd probably start with the O2 sensors, they're cheap enough to be worth doing, whether you continue to use your current cats or replace them.
I'm a fan of sport cats. I've had 200 cell on both my 3.4 and my 3.6 and they're great, they seem to have a seat of the pants improvement in performance (full disclosure: I've never dynoed my car, so I have no idea whether there is any actual improvement). A thing you might need to worry about is CARB certified or original equipment in CA - I don't have the same issues in VT, so don't know anything other than what I've read about the Republik of Kalfornia emissions regs.
Actually one idea I had was to pull the cats off, scope them to make sure the ceramic core hadn't actually collapsed or somehow been mechanically destroyed then if all looked ok I would try washing them with MEK (methyl ethyl ketone). Its a really good solvent for washing away any nasty organic residue, I figure its worth a shot.
It will do zero damage to the ceramic or metallic element, its only an organic solvent. In a best case it washes away enough gunk on the cat to up its efficiency enough to clear the code. My wife has loads of MEK at her work so I could get it from her.
Also good idea for trying to swap the O2 sensors from the banks to see if the code follows, I can try that this weekend.
EDIT: looks like acetone might work better
It's possible the cat element inside has come loose, in which case you may be able to open it up and re-weld the element.
Once the cat is off the car, you can shake it and you will be able to see and feel if the element is loose.
Ahsai, Can you elaborate on your experience with Carnewal's 200? Can' t remember where you live but you don't have problems with emissions test or cel's? You ship them over to Belgium, if so do you remember costs (I haven't contacted gert about that)? Looks like a really inexpensive option if someone could live with the time it takes to rebuild
Sure. i have a thread
here
.
5yrs and 26k miles later still working well and passing smog (OBDII style smog check, not tailpipe. Not saying it won't pass tailpipe test though)
I replaced my cats with MagnaFlow units bought from Summit Racing. I bought the CARB certified units for about $1200 for both. About a year and 10K miles ago and still no error codes.
No, I don't add to the intake. Mix with the gasoline. I usually put 2 cans of seafoam in a 1/4 tank of gas, drive it hard for about an hour, and then refill with top tier gasoline.
That's what happened to mine. The element is loose and I can hear / feel it moving around. I've been contemplating between going with Carnewal or just re-welding the original element - which only has 36K miles on it.
In the meantime, I bought a cheap set off RLister. Chris, if you're interested in cheap OEM replacements (I think they have 80Kish miles on them), I'd be willing to fix my original set and sell you the pair that I bought at what I paid. PM if you're interested, it will be your cheapest option by far and I believe you're close to me - I'm in South SF.
I've wondered the same thing, because I just recently changed my engine air filter and noticed the throttle body was dirty. I've used a lot of CRC products in the past, and unless some of the Porsche gurus say otherwise, that's probably what I use over the seaform on the throttle body.
Maybe I wasn't clear in that post, but I only use top tier gasoline from either Shell or Chevron at 93 octane. The seafoam was added to kick start my lazy no good cat that love sto sleep in the garage. Seafoam woke it up within minutes of driving.
Did anyone actually do this? All the converters that I've ever taken apart has the element held by a stainless steel mesh against the converter wall. It was friction fit. Are the 996 converters different?
The part numbers I used were 444066 and 444067. One quirk is that the non-CARB version included the attachment clamps but they didn’t include them with the CARB version. I called Cody at MagnaFlow at [phone removed] and he shipped them quickly with no questions asked.
I forgot to mention if you have them professionally installed they include a 5 year 50,000 mile warrantee.
I think I may have one good one from a 2000 3.4 in the garage attic that you can have for cheap. The other one has a loose core, replaced them with 200 cell cats. I�ll have to check to see which side is good...
Carnewal is best/simplest if the cats are rattling around. Mine passed smog no problems but then the motor IMS blew up. I now have a set of 997.1 cats that I'll be selling here in the next few weeks. PM if you're interested. I'm in SF Bay area.
I chased this for years. First replaced my cats with a aftermarket crossover set. At the same time went headers and aftermarketa mufflers. Code went away and passed emissions both OBD2 and tailpipe. Year or two later came back. This time changed all four o2 sensors .code now gone since last summer.
Along the way I did use o2 extenders to get passed emissions. Found some cheapies on Amazon that worked. Problems was car seemed to run rich and performance wasn't right so I removed and lived with the the code until I replaced the o2 sensors. Should have started with the o2 first. Never got a specific o2 code, just the low efficiency code p0402 if I recall.
I can send you my extenders if you need them for emissions. Just pay for the ride. They aren't top quality but they work .I wouldn't use them long term. I'd offer up my old exhaust but I am an 02.
I believe so. The 997.1 cats are very similar to my 996.2 cats so I'm assuming there wasn't any design changes over those few years (2002 thru 2007). I actually used all of the '02 mufflers etc since I'd already done the Carnewal change. They fit perfectly on the 997 motor.
If you've taken yours off already, we can meet up and compare if you're in or around the Bay Area.
No.
Like this:
Amazon
Amazon
Or this:
https://www.aliexpress.com/item/90-A...827996904.html
But you can make your own ( like I did) using a some spark plug anti foulers like these:
https://www.canadiantire.ca/en/pdp/d...-0245609p.html
I completely missed the subject here, thanks.
I have a few sets non-foulers if anyone would like to have them before buying anything. They worked for me on a different car. PM if wanted.
This is a source reference. Confirm exact model applicability in the original material.
