Clogged CAT

 

Yep, bad kitty.

 

let us hear the good sound when your done.and also let us know if there is any improvement on idle etc......

 

So i just had my cat replaced under warranty and two days later I have the glowing ring around 02 sensor. I did not have the glowing ring before they replaced my cat. Could this just be my 02 sensor has gone bad?

2004 GT 6M 84,000km. no Mods. Just had one coil and both leading spark plugs replaced last week because they were burnt/fouled. All plugs coils and wires were replaced at 76,500km.

 

they did it wrong.

or your new cat is already misbehaving, bad kittie

 

I took it in to them and they told me it is just because it's the old O2 Sensor. ******* Mazda. They said this is typical and they also told "how could something be wrong we just installed a brand new one for you."...........

 

do you know where to find information so I could bring it in to the dealership to prove they dumb guys wrong.

 

This is not normal operating condition, that's all they need to know. If they don't like it, find another dealer since these ones won't know how to fix it right anyway. Do so quick as this will murder your engine if left alone.

O2 sensors don't glow.

[edit] wait a minute. You had plugs and a coil replaced after less than 10,000km? That is not normal. What were the symptoms observed that necessitated that repair? Also, what was the reason for cat replacement in the first place? How's your fuel economy recently?

Check that the coils and plugs are plugged in in the right order. This is fishy, either the new cat is defective, which is weird, or you're dumping massive amounts of fuel into it, which could point to a larger problem.

 

the engine would mis-fire after redlining in 2nd, then climbing to 7,00rpm in 3rd gear. they first didn't tell me why the spark plugs were fouling so quickly so i emailed the manager and he said there was probably carbon build up when i first got them replaced so it caused the new ones to foul. But I still got the mis-fire code after the 2nd set of spark plugs in. So they changed the CAT. I still got 5 pending mis-fir codes after the new Cat was installed. but the CEL did not stay on. So i've been to mazda 4 times in the last week and a half. second time i went it was cause i had a pending mis-fire code. but they told me i was imagining it.

I'll have to get back to you about fuel efficiency need to check in my car what i'm at.

 

engine also starts up differently now that new CAT is in. Feels like it is struggling then starts up. And I have bad fuel consumption. 15L/100km.

 

You have something else wrong and it's killing your 2nd cat.

Misfires CAN be caused by a failing cat, it's possible. However, the presence of misfires usually means that ignition is failing, and failing ignition dumps lots of extra fuel into your cat which rapidly kills it.

Your ignition is relatively new, so I'd say that there is something else wrong that is causing your ignition to act like it's failing. Alternator failing, engine block grounding problem, e-shaft sensor fouled or the profile is skewed, MAF dirty or failing, vacuum leak, or wires mismatched.

 

I would stop driving until you get this figured out. I'd pull all 4 plugs and check their condition and make sure the wires are connected correctly... take pics of the plugs and put them up here, (and remember which one went where so we diagnose the right rotor).

The manager's explanation about residual carbon fouling a sparkplug makes no sense.

 

I Know there are plenty of DIY spark plug removal but I lack the ability to do them. I have checked the wires and they are going to the correct spark plugs. I was into Mazda today and they say they can not find any codes since the CEL is not on. But they have check the alternator and they say it is fine. They now took a bunch of specs and are sending them to the engineering department at Mazda Canada. So the manager said he will call me later today with what they say. I had a compression test done 2 weeks ago and they said engine has excellent compression. But is there a still a possibility it is not operating properly?

 

something else to think about...u may have an injector stuck open(or just not sealing closed) causing exssesive fuel to be dumped in the housing at the wrong time.
I really dont think its ignition if your coils wires and plugs are relitivly new...something some where is telling it to burn to much fuel, whether its the MAF not getting the right air flow numbers, or if maybe that O2 sensor is messed up causing the rich condition.
If your old CAT went thermal and had a melt down, its possible that the O2 sensor melted down with it. just a thought

 

Engineering is having them run a bunch more tests. So I will fill ya'll in when I get the word of whats going on. And I will be looking into going to another dealership from then on.

 

Here's a pic of the Glowing cat. One week later and still waiting to hear back from Mazda about it

 

Highly highly recommend you don't drive like this. Glowing cat means it's operating above it's normal temperature which will kill the cat, but moreover, if it's clogged, your engine is operating at higher exhaust pressure and temperature than designed, which will kill it in turn. It won't *necessarily*, but it's a risk I wouldn't take.

 

Could Carbon build up be causing the cat to glow in any way?

 

if it were carbon, it would burn away and be done...there is something else going on here. There is something feeding this CAT glow and the only thing it could be is fuel. For some reason the motor is running to rich and the CAT is trying to burn all the excess gas off.

 

A post-MAF air leak can cause the mixture to run very rich, and cat to glow.

You'd think a leak would make it run lean, but the O2 sensor sees lots of excess oxygen and continues to dump in fuel.....

 

Sorry i didn't add in a part about the carbon. Could there be carbon build up by the injectors causing them not to full open/close properly? Or anything carbon in the engine causing not to run properly. causing it to run rich

 

http://www.ehow.com/how-does_4899148...-o-sensor.html

"An oxygen sensor heats up in the exhaust stream until it is glowing red and senses the amount of oxygen in the exhaust..."

My ring glows slightly too. I freaked out a year ago when reading things here, and had Mazda check it. They said it "tested as efficient." In googling around, it sounds like it's normal for (just) the O2 ring to glow.

 

I assure you, that it is NOT normal to see any glowing from the outside of your exhaust system.

Your quoted line there is disregarding the fact that the part it's referring to is inside the exhaust stream, not visible from the outside of the exhaust stream. And when you see the glowing ring around the O2 sensor, that is the metal of the cat wall itself. It just starts there because the metal is the thinnest with the least amount of insulation. It's not the O2 sensor that is glowing, but the metal around the O2 sensor.

And as stated, this is NOT normal.