I have been driving with two shot catalytic convertors on my 00 Maxima A/T for about 5k miles (104k now). Ever since the SES light was on, I was told to replace my spark plugs, ignition coil (#3), o2 sensor, starter, alternator, ignition switch, battery, and now ... my catalytic convertors (both). Dealership wants $2.3k two replace both + labor. I called DaveB and he quoted about $1.1k for both so I knew the dealership was trying to rip me off. To be honest, I don't know what headers or y-pipe or b-pipes are so bare with me ...

I want to know if there are other alternatives to replacing both my cats because they are shot. (Examine by Nissan Mechanic) If possible, let me know the price as well. Feel free to flame/comment/suggest feedbacks. Any help will be appreciated, thanks in advance!

 

$2,300 is a lot of money...

 

If they are shot, then they need to be replaced. It is illegal to remove them entirely, so don't think about going that route.

What SES code do you currently have, what problems do you have now?

 

Well I had P0430 but that code went away after I replaced my ignition coil #3 (Thanks DaveB) after about 200 miles another code popped up P0420. I know they need to be replaced but I don't have $2.3k to give away. That's about half the price of what the car is worth. Problems I am having are slow acceleration and VERY poor gas mileage. What other alternatives can I do?

 

Rear cat:
http://cgi.ebay.com/ebaymotors/Catal...spagenameZWDVW


front by radiator (bank 2 actually)
http://cgi.ebay.com/ebaymotors/NISSA...spagenameZWD1V

These are not OEM but will work just fine and will save you more than $1000 bucks. Bring it in to a muffler shop or better yet to a local mechanic (not the dealership nor the big chain store).

Hope this helps, P0420 & P0430 are a pain in the *** codes and will only go away with sims or new cats. Good luck.

 

What 02 Sensors did you change?

I could just be the downstream 02 sensors giving you that faulty code, but if your running sluggish it could be something more serious. Also might need a ECU Reflash if you haven't gotten the update software.

 

I still have my front cat and my y-pipe from when i installed my XS power y-pipe & headers. Send me a PM if your interested the y-pipe has a blown flex pipe but i can weld a new one in if you want. I also have a brand new random technology high flow cat for sale just let me know.

 

Wow! Thanks alot nsnrider, you just saved me a fortune! One quick question, I am a little skeptical of ebay sometimes ... and I was wondering if you know the seller.

My dad's mechanic replaced the 02 sensor for me but he doesn't remember which one ... wth? Anyways, is ECU reflash updating the firmware to a new version? If so how much is it and what will it update in my car?

Thanks for the offer but I think I'm going to stick with the regular stuff. I like quiet rides :x

 

would u trust that FRONT PRECAT from ebay?

How about the Eastern Precat from autopartswarehouse.com
http://www.autopartswarehouse.com/de...EAST40387.html

 

Im talking about stock parts, I have a used front pre-cat in great condition not some Chinese made ebay junk

If you want i can post a pic

 

^^ if he doesn't want it, how much are you looking to sell it for?

 

If you are interested in purchasing solid products from a reputable seller, we sell the Maremont bank 2 pre-cat for $279.99 as an OE replacement.

For the rear cat, I heartily recommend the Cattman FastCat, which is on sale right now for just $189.99, our lowest price of the year. The FastCat is a 300-cell, all-metal cat with a low-turbulance stainless steel body and thick 3/8" flanges (nickel-plated) that are welded on, not floppy crap. It is completely street legal AND flows as well or better than any cat available for the Maxima. You should pick up 3-5whp.

Better get that Bank 2 pre-cat replaced before your motor starts sucking sand and destroys the Bank 2 cylinder walls.

Give us a call to order or ask questions, if interested. 800.759.9920, open 9-5 MST, M-F. If you're not familiar with our company, just ask around for references. Check out the Cattman End-of-Year Sale in the max-org GD forum for some great deals.

Brian

 

I was thinking around $100 + shipping or send me a offer its obviously not new but all the honeycomb is intact and was working fine when i took it off here are some pics...

 

Thanks for everything guys, I'll look into all the feedbacks.

 

I don't have any feedback yet since im new to the forums but you can look at my feedback from rcuniverse.com from when i used to be into r/c cars and my ebay feedback...

http://www.rcuniverse.com/community/...s&memid=180626

http://feedback.ebay.com/ws/eBayISAP...All%20Feedback

 

If that would really fix my p0430 I would so be super excited.

How many hours labor (a little too big of a job for myself) 3-4?

 

Well i would say 3-4 hours if everything goes smoothly but if you break a bolt your in trouble but i had good luck with all those bolts i think i couldn't get out one bolt on my whole y-pipe install excluding the main cat bolts which were all rusted solid but you don't need to touch those Although if you don't have a decent amount of mechanical experience i would have your mechanic do the job

 

how much do you think a mechanic will charge you for installing the two cats?

 

My bro's a mechanic and i looked up what the estimated time should be for a mechanic to replace the cats and it looks to be around 2-3 hours so figer around $75 a hour so around $200. But you really just need to go to the shop get a estimate to be sure.

 

hey brian, what do you mean the bank 2 precat, is that the front PRECAT?.......because if your selling the OE style PRECAT (CLOSEST to the radiator)....THEN I WILL purchase one from you ASAP!.........also do you sell them with the gaskets and bolts???

ill be giving you a call tomorrow

 

FWIW, I think that hi-tec22 and I figured out that he's got two bad pre-cats - the main cat may or may not be working, but the ECU won't know either way since there is no monitoring O2 sensor looking at the main cat.

The dealership told him he had two "inefficient cat" engine codes for bank one and bank two, which means not just replacing the front pre-cat, but the entire y-pipe (which contains the rear pre-cat).

There are three possible solutions, as I outlined with hi-tec22:

1. New OE replacement parts (not performance), which would be the front pre-cat and y-pipe/rear pre-cat. I suggested the Maremont products we sell, but of course there are Nissan and perhaps some other sources for this.
2. New OE replacement front pre-cat and a Cattman performance y-pipe. Cattman performance y-pipes position the secondary O2 sensors so that both are reading the front pre-cat, so the ECU doesn't realize that the rear pre-cat is missing. Of course, this setup would not be street legal, but if done properly, could pass emissions.
3. New Cattman header/y-pipe system, which replaces the pre-cats, y-pipe and manifolds. This will require either an O2 simulator or relocation of the secondary O2 sensors behind a working main cat. Of course, this would not be a street legal setup either, although if done properly, it could pass emissions.

I did not suggest a possible 4th strategy - integrating an O2 simulator to simply get rid of the CELs, or relocating the secondary O2 sensors behind the main cat - because the failed precats cannot be left in the system. The ceramic substrates will start to decompose (if they haven't already), which means that sand is getting sucked through the exhaust valves into the cylinders, and will destroy the engine.

Brian

 

I don't know the seller, I am just giving you some examples of other options that you have beside expensive new oem parts. I ended up purchasing used cats since I didn't have time to wait for them to arrive (had to pass inspection in two days).

Anyways, I have a lift and power tools, took me about 2 1/2 hours for the job, i did break one stud and had to drill it out.

 

Now with option 2....I have two questions,

1) Does this mean that the o2 sensors in the y pipe would have to be MANUALLY REWIRED AND/OR SPLICED?

2) Would the option 2 setup cause the CEL light to come back on at some point...and if it doesnt, what would be needed to consider it "done properly"....as to pass emissions?

thanx

 

ok I'm a little confused. I have a code that says one of my cats is dead. So is there only 1 cat that it could be, since the 02 sensor is behind only 1 of the cats? Also where are all the cats located on our maximas? Also how does a bad cat destroy the engine, b/c wouldn't all the dirt and ceramic substrates( I don't rly know what those are) be pushed out the tail pipe since thats the way the exhaust is going, and not into the cylinders?

 

IM HAVING THE SAME PROBLEM BUT IM GONNA JUST HOLLOW OUT MY PRE CAT...BUT WHATS THE PROPER WAY TO REMOVE THE FRONT PRE-CAT

 

Since it appears that you have a 2001, it has to be CA/NLEV-spec emissions, so all of this applies...

No, a "dead cat" code on a CA/NLEV emissions car means that one of your 2 pre-cats is dead (or you have bank 1 and 2 codes and they're both dead), just a matter of which one. There is a different code for pre-cat failure on each bank, you just need to determine which keeping in mind that if one goes bad, the other will likely follow before long. Original pre-cats are living on borrowed time in any 99-01 CA/NLEV Maxima.

A dead cat code never means that the main cat is bad because there is no monitoring O2 sensor behind the main cat. The ECU doesn't know if its there or not, it only "watches" the pre-cats.

The bank 1 pre-cat (rear, next to your firewall) is integrated with the y-pipe on all 95-01 Maximas (Federal, CA/NLEV, all the same) - repeat, its not a seperate object, it cannot be seperated from the y-pipe. [It is a seperate component on 02/03 Maximas.]

The bank 2 pre-cat is a seperate component on 99-03 CA/NLEV Maximas, located in between the short front manifold and the front downpipe of the y-pipe.

Maybe this will help you sort out the three options in the previous email, ranging from simple OE replacement w/ all street legal cats (no performance gain), to a "hybrid" solution using an OE replacement front pre-cat and performance y-pipe (w/o a rear pre-cat, but still avoids a check engine light), to the highest performance solution of replacing everything between the engine and main cat with a header/y-pipe system (no precats, but no CELs).

There is an overlap between the intake and exhaust cycles on almost any motor, when the piston begins its downstroke before the exhaust valve is completely closed - that creates negative pressure that "inhales" a little bit of exhaust (and ceramic dust if the pre-cat is disintegrating). Its not a maybe sort of thing - this does occur in CA/NLEV-spec 99-01 VQ30DE motors, and its not uncommon.

Brian

 

Thats a great explanation for a very confusing issue. thank you.....

But why are the pre-cats failing?

 

Cats are basically a honeycomb of inert material (either a ceramic block with thousands of holes drilled through it, or an intricate network of thin metal foil) that is impregnated with the rare metals platinum and palladium, which create the catalyzing process that "neutralizes" various internal combustion exhaust gas constituents.

Sort of like a battery (non-rechargeable), every cat has a finite lifespan. As the vehicle is operated over time, the catalyzing elements are used up - molecule by molecule - until the cat's internals are spent and catalyzing efficiency starts to fall off. Some cats have higher quantities of catalyzing elements than others (platinum and palladium are both extremely expensive), which is why its important to buy cats that are EPA-approved - they have to be warranted for 50k miles (if I remember correctly). Cats that are not EPA-approved (sometimes called "race cats") oftentimes have shorter lifespans.

As long as we're talking about cats, I'll mention two things that will kill a cat dead long before its time - clogging it up with carbon and/or toasting it with extreme heat. The presence of built-up carbon AND extreme heat can actualy start a super-hot fire that will melt the interior of the cat. Excess carbon typically comes from running too rich (and/or plugs that are too cold) and extreme heat can come a few things, from running too lean, nitrous, some turbo setups, etc..

Brian

 

hey Brian,

Could u answer my questions in post 23....i believe u may have already answered my 2nd one....im not too sure

 

Thank you, this is great info and very appreciated.

 

Sorry I missed this earlier.

1. O2 sensors that are positioned in the y-pipe do not require cutting and splicing because they're still more or less in the same positions (solutions 1 and 2). Just about any header installation requires extending and/or splicing sensor wires.

2. Never mind the fact that there's only one pre-cat, there's no CEL if the O2 sensor ports are positioned properly in the y-pipe. In fact, its very reliable.

I should mention here that of course any emissions strategies I'm discussing that exclude Nissan or EPA-approved OE replacement emissions equipment are intended for off-road (track) use only, and would not be legally permitted on public roadways.

Brian

 

ahhhh SEE!, thanks for the clarification bro...and your Y-pipe has the o2 sensor bungs, as ive noticed