newguy

started the car after work, after a couple sseconds the engine developed a miss and CEL was flashing, this is engine miss Ive read and prob bad coil pack, theyre original w. 64k miles (I know waited too long) Not a prob i ordered coils, wires, plugs no biggie.

My question/concearn, I drove it a bit to park in a good spot to tow home tomorrow and ran it for about 20 minutes. Im sure its coild b/c it started running normal for about 2 min during which the CEL stayed on solid, coils could be the only intermittant prob among coils, wires, plugs I think.

After running 20 min I smelled burning so I got out looked under car and cat was red hot glowing around 02 sensor bung and front flange (not good). Do you think I heated up the cat by dumping unburnt gas into it for 20 min by 1 rotor not firing or was a clogged cat my problem from the beginning choking the engine causing the blinking then solid CEL?

Guess Im asking if the cat gets red hot glowing have I melted it inside? Or could it be good still? I know cat is a problem area, is visual insp only way to know 4 sure?

Mazurfer

My guess is...and it's only a guess................"Do you think I heated up the cat by dumping unburnt gas into it for 20 min by 1 rotor not firing" However I have to be honest and say that it could have been the CAT from the get-go......but not sure that it would flash the CEL first. I think it's more likely a coil at 64k on them and the CEL was flashing first.
You can unbolt the cat at the front and get it away enough to have a look inside and see if it's still intact or not, but one way to know for sure......and that's after you get the new coils and plugs/wires in it.

Might wanna wait for someone with more experience than me, but let's see what the consensus is.

You have a code reader for debug after the initial go-around?

Jon316G

iTrader: (1)

That's what I'm thinking.

TeamRX8

iTrader: (25)

Unburnt fuel + hot cat catalyst process = blow torch

newguy

my thoughts exactly but do you think the cat is ruined in 20 minutes? Ive got coils/plugs/wires ordered on overnight delivery so if it runs Id rather drive it home than tow it of course. I guess I'll know once It starts up without the miss, if it dies cat is clogged. Dropping the cat in the work parking lot might not be an option, Id have to get it towed home then take a steel pole to the cat until the midpipe arrives.

Jedi54

iTrader: (7)

nope

xun4gvn4everx

iTrader: (2)

The good thing is you are under warranty, so you can get the cat replaced for free if that is the issue. If that is the case, I would recommend getting the free cat from the dealer even though you are replacing with a midpipe, since one; they are expensive and two you need it for emissions. Unless you ordered just a highflow cat midpipe. In that case, I would get the free cat anyways a sell it.

TeamRX8

iTrader: (25)

Try again .... except this time don't assume you know exactly how hot the substrate was

xun4gvn4everx

iTrader: (2)

^ He was talking about the probability of it being ruined. And I agree with Jedi, that nope, after 20 minutes, the chances of burning up the internals is very unlikely.

TeamRX8

iTrader: (25)

As usual you don't know anything except what other people post. It all depends on how hot it got.

One flooding has ruined hundreds if not thousands of RX-8 cat converters and it didn't take anywhere near 20 minutes for it to occur. 20 freaking minutes of continous misfire isn't just a lot, it's a ton. This is why the flashing CEL misfire modes are programmed into the system inthe first place. If the cat was glowing red then the substrate was certainly hotter than the known OE substrate failure temp.

So the question was " could it fail?" and the answer is yes it could. Nobody here knows if it failed; not me, you, or anyone else until it's examined.

MazdaManiac

iTrader: (3)

CATs are funny creatures.
Dumping fuel into can heat it up or cool it off. It depends on the available oxygen.

A sustained misfire could get it insanely hot. If it was over 2k°F for too long, it might have melted.

However, the typical failure mode with these symptoms usually start with a failed CAT, not end with one.

newguy

thanks for the input, Im hoping Jedi is right, one thing in my favor is it was snowing and only 35* outside with a strong wind blowing. There was small amount of smoke coming off the outside and O2 sensor bung was glowing cherry red but it cooled back to rust color within 5min.

Not completely related I have seen my OEM cast iron exhaust mani in my Talon glow completely red after 2 back to back drag runs at 27psi with no damage to front 02 sensor or turbo, but there was no cat substrate involved there.

Good point about new cat from dealer, Ill drop it for sure to check

Thinking about timeline of events, the missfire happened immediately on a cold motor so I doubt cat caused that and it never cut off or was choked to stall by no exhaust flow right up to when I cut the key off. It would idle lumpy with clutch pedal pressed. It did stall when I released clutch in neutral and flooded, starting again after I performed de-flood procedure using accelerator. I was raising idle to 2-3k rpm during the 20 min period hoping bad coil would fire up again as it did once for a 2 minute span during the 20 min event.

Mazurfer

Hmmmm.....now I might just be back to what I originally thought after this "new" data.

newguy

Update:
I managed to find a dealer that didnt rape on coils Wyoming Valley Motors in Wilkes-Barre PA $40 each only about $10 too much, but Berger Mazda in Hazleton PA $79, Kelley Mazda in Scranton $72 (*******, I know who NOT to goto for svc)

But wyoming valley mazda only had 3 in-stock so I took em. I gambled and changed both for rear rotor and the leading coil for front rotor, in the parking lot at work today. Fired up and purred like a kitten but solid CEL still lit. I thought rear 02 got burnt up but it ran better than ever smoother idle no vibration of dash so I drove it to Advance Auto to read the CEL. It was just a residual CEL for Missfire cyl 2 (rear rotor) so I got lucky and guessed right by changing both of those coils. He cleared cel and hasnt come back, no other codes for rear 02.

Rear coil(s) were going bad when I bought it w/ 55k miles Im sure now, it always vibrated at idle and required a gentle clutch starting off in 1st gear for asmooth start. Now 1st is easily modulated, feels like a new car and easier to drive also pulls harder to redline and feels faster overall, mpg is better as well.

So Ill check cat myself, not taking to stealership b/c theres no codes and theyll charge labor if nothings wrong. Stopped a few times during a 50 mile trip from work to Advance to home and cat didnt smoke/smell and no glowing red so I think its ok.

I ordered 4th coil for $33 shipped online and got NGK Iridium plugs for $16 ea and NGK wires for $25 from Amazon, great deals I thought for a grand total of $250 for complete ignition system, could have been $21 less for coils but I needed them today, Im out of town Mon. for work. I wont need to drive it till plugs/wires/coil come in and wrench myself. could have been much worse, whew.

Im ordering an OBD2 scanner after this post, a good investment that Ill need in my time with the 8 plus I can use it on my other cars (although theyve never thrown a cel) love/hate with the 8 I guess.

xun4gvn4everx

iTrader: (2)

Glad you got her running better bro. Hopefully the cat is still good and then you are set

Mazurfer

Great.......glad it worked out! Yeah, get the new plugs/wires and that last remaining coil in there!

OBDII scanner is really worth it, I have a mo betta one now, but here's a decent one! Let's you monitor a lot of stuff and read/clear codes. It will save a lot of time and aggravation! Looks like they have free shipping right now as well.

http://www.scangauge.com/


"So Ill check cat myself, not taking to stealership b/c theres no codes and theyll charge labor if nothings wrong. Stopped a few times during a 50 mile trip from work to Advance to home and cat didnt smoke/smell and no glowing red so I think its ok."

Sounds like it might be, although I wouldn't suggest flooding it too many more times. Not sure if you saw it, but you can take the CAT all the way off or just take the front bolts off, move it just enough to the side where you can look into it with a flashlight and see what it looks like.