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-   -   rumors and catalytic converter. (https://www.rx8club.com/series-i-tech-garage-22/rumors-catalytic-converter-247545/)

DCIrish 07-27-2013 10:41 PM

rumors and catalytic converter.
 
Bottomline... had flashing check engine light. solution... replacing wires plugs and coils. ALSO loss of power which COULD be the coils etc... but while reading I heard that CAT could be the issue also. TEST- run the car hard... see if the CAT is glowing. I did just that. the entire CAT was not glowing but I did see glowing from oxygen sensor and some ports "down stream" of the CAT. not sure whether this is still indication of CAT failure or not. incite appreciated. Thanx :)

RX8Soldier 07-27-2013 10:55 PM

It is a sign of failure. But, the best way to tell is to pull down the cat, shine a light inside and visually inspect.

A weak ignition leads to a ruined cat. But, it also works both ways. Stop the cycle before you break the bank.

nycgps 07-31-2013 09:02 PM

you need to search.

Karack 08-01-2013 01:07 PM

a visual inspection is always the best, remove the flange bolts and drop the cat and see if the catalyst looks like a nice honeycomb pattern across the whole face.

a glowing cat under hard driving conditions is perfectly normal, and i have no idea why anyone would say it wasn't.. if the whole catalyst was a nice bright amber/yellow color, maybe. some slight glowing, no.

DCIrish 08-01-2013 08:56 PM

that's really the question. the WHOLE CAT wasn't glowing. Was reading a bit and said if the cat was glowing that it could be a bad sign. I figured there might be some glowing naturally. So that's why I wrote the thread. Cross checking if you will. I HOPING my coil/spark/wires fix the problem. Still waiting on parts from mazmart though

DCIrish 08-01-2013 08:56 PM

Other than that... the worse part of checking out the CAT is finding a way to do it/ a lift. lol. thanx again guys.

BigCajun 08-01-2013 09:12 PM

I have NEVER heard a glowing cat is " perfectly normal".
Cats glow because misfires dump unburned fuel into the exhaust, where they ignite and cause a blowtorch type effect in the cat, which leads to melting, cracking or clogging the cat, in turn eventually damaging your engine.
Someone please explain to me how a glowing cat could possibly be normal?
If so, I will admit I'm wrong.
These freaking redundant cat questions need a stickie!

nycgps 08-01-2013 09:27 PM

A hard driving = glowing cat is in fact normal, u see that often at tracks. Is it good for cat? No. Is it normal under such condition? Yes

But u shouldnt see anything glow under normal street conditio. thats the point.

BigCajun 08-01-2013 09:50 PM

I don't consider track conditions "normal".
I assume DCIrish was asking about street driving.
I don't know about racing, but if that happens then, I still wouldn't qualify that as normal.
Expected possibly, but not normal.
That would seem to me to be damaging the converter or at least compromising it's efficiency, and shortening it's life.

nycgps 08-02-2013 03:11 AM

Constant high rpm will overheat the cat, even with stock's pig rich tune.

Karack 08-02-2013 05:32 PM

most people just aren't quick enough to see the effects, of course if you run a stock car hard on the dyno i'm sure you could in fact see a perfectly normal stock setup begin to glow.

BigCajun 08-02-2013 06:28 PM


Originally Posted by Karack (Post 4508361)
most people just aren't quick enough to see the effects, of course if you run a stock car hard on the dyno i'm sure you could in fact see a perfectly normal stock setup begin to glow.

Ok, I want to discuss this and I don't want anyone to think I'm being contrary or confrontational.

My thoughts are based on experiences I had as an admittedly not certified mechanic from 20 years ago. Everything I learned was anecdotal, with no formal training, and no experience with rotaries.
Whenever I had a customer with a glowing cat, I would not sell them a converter without a tuneup, cause I had learned long ago that misfires dumped unburned fuel into the exhaust, and ignited in the cat, causing them to melt, break up, or clog.

Believe it or not, I worked for an unethical exhaust & brake shop owner, who tried to make us sell cats to every customer who came in.
I have a conscience, and I refused. I was a pretty good employee, and he left me alone after that.

I worked in a middle/low income area in the burbs of New Orleans, so many times the customer could only afford one or the other.
I would actually use a pressure gauge where I would drill a hole in front of, and behind the cat, to measure the back pressure and determine if it was clogged.
I also used a thermal gauge to measure temps in front and back.
These were, in my opinion, easy visual aids that my customers could see for themselves, and be reassured that I was not trying to screw them.

For those who could afford it, I would do a tuneup and cat, and give them a warranty.
Almost always, the new cat would not glow after that.
The customer was happy, as was I, because I had the satisfaction of helping someone who needed it, and knew I had done a good job.
For those who could not afford both, and I knew the cat was bad, I would recommend the tuneup first. If they knew someone who could shadetree and hacksaw the cat off, I would offer them a scrap piece of pipe, expanded on the ends, and a couple of muffler clamps for a few bucks so they could drive their car until they could afford a cat. You would be surprised at how many would actually come back for the cat.
I got a lot of repeat customers that way who appreciated my honesty.
I also met my wife there, who's '79 Zephyr needed brakes.:)

I didn't want anyone to think I was just talkin out my a**.
I honestly believe it is not normal for cats to glow.

Karack 08-02-2013 09:17 PM

except for one simple comparison flaw, this isn't a boinger. rotary exhaust and cat temps are a tad higher than your average car.

BigCajun 08-02-2013 09:25 PM

Yes, I did say I had no experience with rotaries.
Most everything I know about them, I have learned since joining the Club in January.
I have an open mind, but I still have a hard time accepting a glowing cat as normal.
Maybe with time I will change my mind.
Thanks for the discussion.:)

Karack 08-02-2013 09:36 PM

i wouldn't really call it normal, it does take coercing to get the exhaust hot enough for the cat to begin glowing. under normal driving conditions getting out of the car you probably would never see it, on a hot summer evening after running the car hard and then holding revs to 4-5k for a minute then looking under the car you would probably see the exhaust laboring.

i merely said it for the sake of people who may be running into issues, running around in circles dumping money into a black hole that may not exist.

DCIrish 08-02-2013 09:56 PM

Conversation has been quite educational. ty guys again. I'm HOPING... that the tuneup alone will do it. ANOTHER thing that has been "funky" in the car is the amount of time it takes to ACTUALLY turn over... so I'm really thinking the plugs and coils need the change anyway. Im hoping this will fix my power decrease... but if it doesn't, then checking out the CAT is my next step. I've seen a couple youtube videos of a guy putting acetone into a half full tank to clean the CAT. seems quite risky for a rotary... would you agree? ALSO... the other thing I saw was soaking the CAT in a tub of detergent. I suppose my mentality is KINDA about saving money... BUT the car only has 60K on it so it doesn't seem right the cat would fail this early... although 8 years old... it's not out of possibility

RX8Soldier 08-02-2013 10:10 PM


Originally Posted by RX8Soldier (Post 4505841)
It is a sign of failure. But, the best way to tell is to pull down the cat, shine a light inside and visually inspect.

A weak ignition leads to a ruined cat. But, it also works both ways. Stop the cycle before you break the bank.


Originally Posted by DCIrish (Post 4508440)
Conversation has been quite educational. ty guys again. I'm HOPING... that the tuneup alone will do it. ANOTHER thing that has been "funky" in the car is the amount of time it takes to ACTUALLY turn over... so I'm really thinking the plugs and coils need the change anyway. Im hoping this will fix my power decrease... but if it doesn't, then checking out the CAT is my next step. I've seen a couple youtube videos of a guy putting acetone into a half full tank to clean the CAT. seems quite risky for a rotary... would you agree? ALSO... the other thing I saw was soaking the CAT in a tub of detergent. I suppose my mentality is KINDA about saving money... BUT the car only has 60K on it so it doesn't seem right the cat would fail this early... although 8 years old... it's not out of possibility

:dunno:

BigCajun 08-02-2013 10:10 PM

Plugs coils AND wires.
Those "remedies" you cite sound like snake oil.
I have never heard of anything like that.
If a cat goes bad, it's bad.
Did you get any CEL for misfires or bad cat?
Are you past 80k or 8 years from point of first sale?
There has also been a history of starters needing to be upgraded.

DCIrish 08-02-2013 10:15 PM

hmmm... flashing CEL initially. but it went off after 15 seconds. I think it was p0302 (held in ECU cache). snake oil?

BigCajun 08-02-2013 10:26 PM

Flashing CEL is misfires. Plugs, coils & wires. Misfires kill cats.
Read the misfire stickies if you haven't yet.
Snake oil is a term used regarding phony cures.
A bad cat can not be fixed.
Good luck.

DCIrish 08-16-2013 10:53 PM

I DID do the coils plugs wires today. Success in my opinion. the car needed it bottom line. BUT the power still seems slim. I'm gonna check out the CAT next. The only thing I swa youtubewise was putting acetone/ethanol (I forget) through the system.... which helps burn impurity in the CAT. With a rotary it seems too risky though. OTHERWISE it is removing the CAT and soaking it in detergent. OBVIOUSLY not the same a new CAT... but if it did cleare it a bit even... it would be worth it

BigCajun 08-17-2013 06:11 AM

I disagree, if it's in any way restricted, you can damage your engine.
A cat is a lot cheaper than a new engine.
If it is in any way clogged, or broken up, replace it, gut it and drive it until you can afford one, or get a midpipe.
8 years from the point of first sale is when the warranty ends.
If you had misfires, which you obviously did, your cat is likely bad.
If you replace it and keep your ignition healthy, change it every 30k miles, it would be a big step in
keeping your engine as long as possible.
No shortcuts.
* BTW, mine went bad at less than 19k miles due to a bad coil and plug. I had a CEL for misfires & bad cat. It ran good for a while and I didn't believe it could run that good with a bad cat and misfires. It eventually started running progressively worse at high RPM.
I changed the coils, plugs, and wires, cleaned the ESS and MAF sensor, and did the 20 pedal stomp, it ran better, but still not right.
I took the cat off, the front half had broken up and it clogged the back half.
I installed a BHR midpipe and it runs great now.

Dirtyswiff 08-17-2013 10:30 AM

just pick up a midpipe swap out your cat until you can access yourself, save ur pennies for a new cat if that is in fact what you need. meantime, your car wont be suffering while you contemplate on what to do next.

DCIrish 08-18-2013 07:53 PM

they sell midpipe swap out specifically for rx8?

RX8Soldier 08-18-2013 08:03 PM

have you attempted to read the stickies in the new owners forum? many answers to your questions there...

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