cat converter glowing red problem, with temp measured

so I have a glowing cat converter problem. I have its temperature measured and it seems various parts of the cat have different temperature with the glowing red area actually around 200 C, and most other areas around 200 as well. A few other areas are a little more than 400 Celcius.

Confused.

Why glowing red area's temp's lower?
Does this indicates a cat problem or a combustion problem?
What temperature will trigger a slow down light?

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Could be a misfire with unburnt fuel entering the cat.
Faulty ignition coil would be my first place to look.

 

I believe you need to visit Aldous Voice eminent webpage and read this: https://aldousvoice.com/2012/12/27/ferrari-360-slow-down/

Those Cat ECU’s are prone to fail...

Good luck (and please keep us updated)!

 

They usually fail giving false "slow down" lights and going into limp mode (I've replaced 2!), it sounds like this isn't the issue as he hasn't been getting erroneous lights, but actually experiencing a heat issue that probably isn't severe enough to trigger the light. If the temperatures were higher, I'd be more concerned.

I'm assuming these cats are stock, when my car went into limp mode, the body of the cat on the dead bank was around 150C and the active bank was around 350C, aftermarket cats. I'd be interested to know what component is glowing red, it looks like a smaller area that might be harder to pinpoint with a laser, is that the area around the thermocouple?

The coils are a good suggestion, if they look rusty or if you have gotten misifre codes, it's a $350 job that may take you a half hour, but that doesn't exactly pinpoint what we are looking for here.

 

Very simple solution.

Replace all the coils on that side.

Your coils aren't firing the plugs consistently and dumping unburnt fuel into the cats and instead of burning in the cylinder its burning in the cat.

 

I also read that using a higher octane fuel can lead to more unburnt fuel entering the cat and igniting there... are you using the recommended octane or a higher grade?

 

update, replaced all 8 coils and spark plugs, problem solved.
thank you

 

glowing red is around the rear o2 sensor, not the thermal couple

however, the termal couple itself is the hottest area , around 400 c

aro

 

ok, glowing red comes back after spirited drive. Red slow down light comes up too.
Background: new coil, new spark plug, new cat ecu. bone stock everything.

three observations.
1. it didn't go to limp mode by cutting 4 cylinders
2. after let the car sit for 30 min and pouring cold water onto the cat , i can use my hand to touch the cat without any problem. Start up the car, the slow down light is still there. It only disappears after I clear the CEL code.
3. really nasty drone sometimes when idling at the exhaust area.

Is the cat really bad in this case? the drone is maybe from the cat?

 

have you tried to put both your hands on open ends of each side of exhaust (one hand on each side of exhausts LEFT/RIGHT) and rev it out , usually you can feel one side putting out more pressure then the other a clear indication cat is either blocked or flowing more free then the other side, also try to tap on the cat when cold (obviously) see if you can hear anything in there rattling also another sign the cats broken down, in saying all this your issue may have been the faulty plugs and coils that you have fixed but your older faulty ones caused the now breaking down of your CAT! usually one problem leads to another and causes others but most people see the secondary symptom and think that is the issue not knowing it caused by the primary problem "plugs and coils" then again this may all be wrong. Food for thought though

 

So after 3 months the issue returns? Has it been driven much since then?

 

no, didn't drive that much. first time doing a spirited drive. so I am wondering if it is really a bad cat

 

That's what I'm thinking. Sounds like the issue was never actually fixed by replacing the other components, just not noticed since the car wasn't being used.Think maybe it's time to upgrade to aftermarkets?

 

I unfortunately am an OEM junkie. My 300zx will get every OEM bolt it deserves and so does my Ferrari. People here in china call me derailed or nuts.

so.... u know....haha

 

Come to the dark side....you'll like it

 

OK so breaking it down the cat is glowing red because: there is unburnt fuel that is dumping into the exhaust or something is causing heat buildup or combustion to occur on that exhaust.

First thing that I'd do (if it was me) is work backward from the cylinder.
1) Are the coils firing? - pull plugs on that side and see if all look normal. Is one or more different in white ash, carbon buildup etc.
2) Are the fuel injectors dumping more fuel than they should - As above, any changes in the plugs
3) If above is normal then is there a hole in the headers that is pulling in extra oxygen on one side vs the other? I have long inspection scope and I'd pull the cat off and put the scope in
4) if no holes in the header/exhaust manifold, is the cat on that side appearing normal? I'd pull it and look it over. Maybe even buy a cheap one on eBay and swap it
5) if none of the above, consider maybe timing difference for that bank or valves. (exhaust valves might check with long inspection scope above and/or compression check)

I'll wager it's coil, injector or cat that is blocked... oh and BTW I'm with you, I'm an OEM guy myself.

 

revving it to feel the pressure is easier then pulling off cat and putting scope , pulling headers off etc. Just saying

Whats to say its not a failed cat ? clearly heats building up in there meaning it very well could be heats not being half absorbed by the cat that was once functioning. I know from myself when I pulled both cats off my SL65 they would go red hot after spirited driving , which previously they wouldnt when i had my cats in...

 

Forget the measured temperatures you're getting. Red hot is well above 500C. As others have mentioned, you have unburned fuel that is being consumed in the cat.

 

or a blocked cat?

 

i observed that I have an aftermarket MAF in the LH intake. I swapped left and righ MAF and want to duplicate the glowing red and see if it swaps sides

Question is , how do I duplicate it without driving crazily? can I just let the car sit and rev it?

 

I had the same issue, my indy removed the cats and soaked it in Simple Green for a day, fixed it back to the car and added BG k44 in the fuel tank then filled it up with gas.
Problem was solved and it even engine ran much smoother and stronger.
I hope this will help you and if not it won't harm the car.
Good luck
Hazim

 

I'd be interested to learn the science behind this theory.
Yes, higher octane fuel resists combustion, as compared with lower octane full, but also tends to more complete combustion once ignited.
Thanks

 

what is "Simple green"? and what is "BG k44"?

 

https://www.bgprod.com/catalog/gasoline-fuel-system/bg-44k-fuel-system-cleaner/
https://simplegreen.com/

 

I doubt cleaning the catalyst is going to help anything...the catalyst is reacting to something happening upstream.