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catalytic converor going out?

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Old Jan 29, 2016 | 09:18 PM
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Default catalytic converor going out?

i decided to take my mcss to work tonite. started it up to warm up as i have a lifter tick. car started up fine, was real loud like normal at first (muffler delete) then got noticeably quieter. i didnt think much about it. well when i was ready to leave, i smelled what smells ammonia. i brushed it off, as the rail road is 3 blocks from our house, and they normally load stuff like that. well then as i was driving i still smelled the ammonia like smell. and then noticed, as i would coast and slow down for stop signs, i was noticing glowing embers floating around in my mirrors. i thought maybe i ran over a freshly tossed out cigarette, or cigar. as it was just a quick few embers and then stopped. then got to another stop sign and noticed glowing embers again. did that for the next 2 stop signs i came up to. well i got to work, and was paranoid thinking something was trying to catch on fire. quick popped the hood. no smoke, and didnt notice anything glowing, or smelling hot. quick, looked under the car at exhaust, and it was still dark, and not red or glowing either. so im confused. i thought maybe the resonator packing was blowing out, but the smell has me thinking the cat is going out. is there a specific way to check for a bad cat, i dont notice rattling. as i had a truck that the cat plugged on, the truck wouldnt run right, the exhaust was glowing orange, and it rattled bad. i have none of that in my monte.
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Old Jan 29, 2016 | 10:07 PM
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lol i love how you just kept on driving, theres glowing embers coming from under your car, ehhh, it will go away if i just drive faster.

generally speaking the smell is consistent with rotten eggs, ammonia could be used to describe a bad cat, is it an OEM cat? The OEM resonator as far as I know does not have a fiberglass pack, it is a baffle type design with alternating small tubes.
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Old Jan 29, 2016 | 10:11 PM
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It's not like it was shooting constant embers or flames or anything. Just when slowing down I'd see an ember or 2. Looked like someone flicked a cigarette out of the window.
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Old Jan 29, 2016 | 10:13 PM
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Originally Posted by spawne32
lol i love how you just kept on driving, theres glowing embers coming from under your car, ehhh, it will go away if i just drive faster.

generally speaking the smell is consistent with rotten eggs, ammonia could be used to describe a bad cat, is it an OEM cat? The OEM resonator as far as I know does not have a fiberglass pack, it is a baffle type design with alternating small tubes.
I'm guessing it's the stock cat still. I don't have receipts for a new one as previous owner left alot of parts receipts with the car
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Old Jan 30, 2016 | 01:09 AM
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just take a look under there, pretty easy to identify, the stock cat is gigantic, not uncommon that stock cats clog over time, most stockers are between 600-800 cell count, very dense, easy to clog up.


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Old Jan 30, 2016 | 01:16 AM
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i wasnt looking for shapes when i looked under car when i got to work as its dark here by 6:30pm. i got to work at 7:30p. mainly looking for orange glowing pipes. from what ive been reading, when i get the smell its pretty much done. i just hope itll get me home in the morning. and then ill park it till i find a new cat/down pipe. i didnt notice any reduction in power, and it still idles fine. but hard telling what itll do overnite, being as im sure its in the process of getting warm already. hopefully it doesnt collapse cooling down.
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Old Jan 30, 2016 | 06:51 AM
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Stop driving the car before it catches on fire.Have it towed home if need be before its a total loss.
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Old Jan 30, 2016 | 09:10 AM
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I had to drive the car home again. The car was back to being loud again.. The strong ammonia smell was still there. But took a while to make its presence. I was as easy as I could be on the car getting it home
Never got above 2500 rpms. Got it home. And used my infrared thermometer in the exhaust. I'm getting around 260 at the cat, drops to about 200 ish after cat. Then the resonator measures around 260 as well.

Also, its a stock cat.
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Old Feb 9, 2016 | 07:33 AM
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ordered a zzp catted down pipe for the beast. will try to install next weekend
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