Catalytic Converter Question

Mars · 02-04-2007, 03:12 PM

I just took my truck to install the Volant cat-back exhaust yersterday at a muffler shop. The mechanic looked inside my cats and noticed they were empty. No ceramic inside at all. It just looks like an empty soda can, so to speak. He said it's supposed to have ceramic in there or it won't pass smog. Has anyone else noticed this on their truck? I'm just wondering if it's normal or should I take my truck to the dealership? I just don't want to deal with them. Damn!

Mars

Flippin Pips · 02-04-2007, 03:15 PM

Take it to the dealer.

mickey · 07-10-2007, 10:15 PM

My uncle had the same situation with you. Nissan catalytic converter has no mechanical working parts inside, it is designed to help the flow of harmful gases. There are many reasons a catalytic converter would fail.

There is no choice but dealership

hooligan · 07-11-2007, 01:48 AM

there's got to be something inside. i had my driver's side have the internals go to sh!t and it sounded like an acorn rattling around inside a coffee can. suffice it to say, whatever it was in the cat, got sucked back into the engine, no more rattle but the engine was blown! got a brand new engine around 52,000 miles. oh and two new cats.

garyk211 · 07-13-2007, 06:01 AM

Lost my engine same way.

Sammy Sandbag · 07-13-2007, 07:29 AM

Sounds like you have a 2WD. If so, that "mechanic" wasn't looking at your cats, but your resonators.

Quote:

Nissan catalytic converter has no mechanical working parts inside, it is designed to help the flow of harmful gases.

Ummmm.... No catalytic converters have "mechanical working parts." And Nissan's cats are no different than normal cats, still have the honeycomb of catalysts covered ceramic through them.

BassTow · 08-13-2007, 10:55 PM

The mechanic was definitely looking at the resonators, I replaced mine with 2.5" straight pipes since they restrict the exhaust down to something like 2.125" and are empty.

The two reported blown engines due to cat failures were caused by improper assembly of the honeycomb into the steel cat 'can'. We're talking about the cats right after the exhaust manifold. Nissan cats are supposed to have a honeycomb with a blanket of sorts wrapped around and then pressed into the 'can'. If the blanket is damaged or missing the honeycomb rattles around in the can and as it disintegrates into a fine sand it is sucked back through EGR into engine and sand blasts the internals. Result; blown engine. How long this takes depends on the degree of blanket damage. Many vehicles have 2 sets of cats and the set just past the exhaust manifold are the only ones that I know of that have caused this problem for Nissans. While this is a rare occurance I know that Nissan and other OEM's have taken a lot of measures to prevent this from happening, either in their vendor's or their own assembly processes.

hooligan · 08-13-2007, 11:53 PM

Quote:

Originally Posted by BassTow

The mechanic was definitely looking at the resonators, I replaced mine with 2.5" straight pipes since they restrict the exhaust down to something like 2.125" and are empty.

The two reported blown engines due to cat failures were caused by improper assembly of the honeycomb into the steel cat 'can'. We're talking about the cats right after the exhaust manifold. Nissan cats are supposed to have a honeycomb with a blanket of sorts wrapped around and then pressed into the 'can'. If the blanket is damaged or missing the honeycomb rattles around in the can and as it disintegrates into a fine sand it is sucked back through EGR into engine and sand blasts the internals. Result; blown engine. How long this takes depends on the degree of blanket damage. Many vehicles have 2 sets of cats and the set just past the exhaust manifold are the only ones that I know of that have caused this problem for Nissans. While this is a rare occurance I know that Nissan and other OEM's have taken a lot of measures to prevent this from happening, either in their vendor's or their own assembly processes.

great info BassTow, as i will save this post to show others i wasn't joking when i said, my honeycomb blew, rattled and the miniscule shrapnel got sucked back into the engine completely destroying it! had my engine replaced with a complete new crate motor from nissan. they fit the bill and my cost was $0... got new cats as well, but i'm still leery... any recommendations on possibly replacing them with some aftermarket high-flow cats? good idea or bad idea?

gabriel c. · 08-14-2007, 12:33 AM

reading about cat failure and engine replacement because of it makes me just want to take them off. i dont worry about inspection since theres always a way around it. i did this on my silverado and had no problems. will the titan throw any codes if i remove the cats later down the road? at the pace im going, 06 with 6500 miles, ill be out of warranty if the cats fail. thoughts?

hooligan · 08-14-2007, 01:06 AM

Quote:

Originally Posted by gabriel c.

reading about cat failure and engine replacement because of it makes me just want to take them off. i dont worry about inspection since theres always a way around it. i did this on my silverado and had no problems. will the titan throw any codes if i remove the cats later down the road? at the pace im going, 06 with 6500 miles, ill be out of warranty if the cats fail. thoughts?

yes, it will throw a code. stillen's longtube headers eliminates one of the sets of cats and to compensate they include some 02 emulators to trick the ecu.

As they eliminate catalytic converters, these are for OFF ROAD USE only. Shipped with an O2 signal emulator to defeat check engine lights.

http://www.stillen.com/product.asp?i...AN&model=TITAN

gabriel c. · 08-14-2007, 02:38 PM

how can it throw a code if you are just removing the cat and not the 02 sensors. just wondering how the titan works since i kept the 02 sensor on the silverado and just removed the cat and had no check engine light come on still to this day.

Nuke · 08-14-2007, 04:09 PM

Quote:

Originally Posted by BassTow

... is sucked back through EGR into engine and sand blasts the internals

Whoa! Thanks Bass! I could never figure out how the heck they could get sucked back into the engine.

Unless you were running the engine backwards...

BassTow · 08-14-2007, 09:48 PM

I'm not sure about the ECU logic concerning the range the O2 sensor considers acceptable during initial warm-up. My understanding is the set of cats just after the exhaust manifold were mandated by EPA to reduce emissions during initial cold start by warming up much quicker than the more conventional cats you see on the aftermarket that are only designed to be used further away from the engine. I'd have to agree that to eliminate them would require an O2 simulator be installed, to the first set of o2 sensors, similar to the Stillen set-up, to prevent codes. I don't have to pass emissions testing where I live so I'm not sure if this would pass or not. Seems like if the test didn't require cold start-up and you had another set of quality cats downstream you would pass emissions testing, barring any other problems that could cause you to fail.

On the other hand, for peace of mind, and if you aren't planning on headers, just unbolt the 1st set of cats from your exhaust and check the honeycomb for any movement in the 'can'. If you can move the honeycomb around at all it means it was loose to start with and you've already started sucking the disintegrated 'grit' back into the engine. If you're still less than the 8yr/80K cat related warranty then I'd have the dealer to do the inspection otherwise they could say maybe you did something and would have to pay for it even if a problem exists. Only downside by having dealer do the inspection is that if they don't find a problem you have to pay the cost for the cat inspection. In reality, even though there have been several that have had this problem here on this forum, as long as you check your oil on a regular normal basis and don't have any of the other symptoms (rattling noise, black soot in tailpipe,etc...), odds are very, very good your cats will never be a problem and not worth the trouble. Hope this helps.

gabriel c. · 08-15-2007, 07:20 PM

i would just hate if this happens while out of warranty. when checking the oil what exactly are you looking for? sludge like material, or something that resembles sand? all this cat talk is getting me worried now. lol.

Titan5683 · 08-15-2007, 08:19 PM

Quote:

Originally Posted by gabriel c.

i would just hate if this happens while out of warranty. when checking the oil what exactly are you looking for? sludge like material, or something that resembles sand? all this cat talk is getting me worried now. lol.

Oil consumption mostly. Meaning check to see if there is any oil on the stick period, like in my case due to internal damage from the cats. I had to add 4 qts. after driving 300 miles. That is what I call a little concerning!