I had an odd noise when I revved the engine in idle or park; I heard a wobble/rattle sound as the RPM needle went back to normal idle.

Replaced the bank 1 front pre-cat and sure enough the catalyst material inside was loose.

 

just a correction, the bank 1 cat is the one closest to the firewall, bank two is closest to the radiator ...



sucks i need the one in the back

 

Those of you that have replaced the cats are very lucky. Good thing you noticed the problem and replaced the POS.

(Yes, I'm announcing this again lol)
If you do not gut the cats, replace them or get headers, your engine will be ruined. End of story. It's a ticking time bomb. Even if you have lower miles and think you're safe... WRONG. At 75k they ruined my engine and I didn't notice any symptoms until it was too late.

 

Correction? What needs correcting?

The one we replaced was at the firewall, which is why I said bank 1.

 

What he ^ said. I can see how it can get confusing. To me both cats on the manifolds are front cats or pre cats. Out of these you have a front (bank 2) or rear (bank 1).

diff things u can call them

front front cat
front bank 1 cat
bank 1 pre cat
front pre cat

front rear cat
front bank 2 cat
bank 2 pre cat
rear pre cat

when refering to rear cat I think its the last one under the car after both sections have joined.
When someone says rear pre cat I think manifold closest to the firewall.

 

wait i'm confused now

when i looked up replacing the cat in Alldata, it only had the main cat listed as a cat on Maximas .

The California spec Maxima had the precat closest to the firewall as a secondary cat.

can anyone correctly identify how many cats our cars have from the factory???


i'm getting conflicting information.

 

3

a "precat" on each bank and the main cat

 

they rattle. At least rear ones mostly. Front ones when u take them out u see chunks missing. Not good....

 

That sucks! Was your engine light on when you had this problem?

 

You'd be wise to pick up the FSM and go over that, it's always 100% correct however what I found is a conflict going from FSM into parts stores that name parts differently. So annoying. I'll also use www.courtseyparts.com to get another idea of what stuff is called and how much it'll cost.

 

yeah i DL'ed the FSM from nicoclub and from what i have seen it doesn't list the bank 1 ( Y pipe section ) as a cat converter. It's called " exhaust tubing " or something like that


I also physically looked at my radiator side precat and it looks nothing like the pic in courtesyparts.com bank 2 precat.


i'll have to take a pic when i get a chance because i'm really confused at the moment

 

I thought 2000 was different from 2002, and I have the cali emission spec and I know the california emission spec was different than all others.

 

"2001 maxima"

are both pre-cats the same part

I just put in all new coils and also an o2 sensor

check engine light still on, now coming up as a bad cat

car runs great though, doesn't miss at all

 

If its throwing p0430, its the front bank pre-cat. If its p0440, its the rear bank pre-cat. Different part numbers.

 

had it scanned yesterday, codes are

P0430

and also

P0160

ok just ordered the cat from discountcatalyticconverters.com

should I look into any gaskets ?

 

Does a bear poop in the woods?

 

Lol. When I bought mine. It didn't come with a gasket I don't believe. It's been awhile.

 

Why risk things? Just pickup the gaskets.

 

 

Where'd the rest of my post go?

I used 02 spacers. 0430 code went away. I may be facing reduced mpg though and am checking over the next few weeks.

Someone above was talking about the pre-cat jacking up the engine. I have heard the contrary from a few mechanics though. Not trying to confuse the issue but I guess I will.

 

Pre-cats will screw the engine when they fail and become brittle, break down, and end up getting sucked into the combustion chambers scarring the walls and causing other catastrophic headaches.

With the 02-03 pre-cats so close to the engine and so close to heat, they are likely to fail and become troublesome than they are of helping anything.

My car has not had any pre-cats since October of 2004 and it's fine right now, 6.5 years later and 90k miles later.

 

That's the problem, crazys. If you ask trained mechanics, they look at you like you're an idiot for asking if precats can get sucked backwards into the engine, damaging the walls or rings. If you ask someone on The Org to explain how they can seriously turn logic on its head and cling to this belief, they look at you like an idiot for daring to apply critical thinking to the problem. "U DONT NO N()()B STFU AND STUFF!!!!11oneone``"

Try Googling pre-cats and engine damage and see what you find. Shock! Only Maxima forums and one MR2 forum mention the two. If pre-cats could get sucked backwards into the engine through super-aggressive VVT, you think you would read about it all over the internet, since so many engines use some form of VVT these days.

Pre-cats are all the rage these days.

 

@ "super aggressive VVT"

 

Holy hell, got bank 1 pre-cat replaced and now I got the MIL for the bank 2 pre-cat.

Soon as I can I'll try to grab pics of the old versus the new.

 

Your case was a fluke and you are spreading FUD.

 

And all my cars have had pre-cats since they day they came off the line without any issues. You sure it wasn't that mythical unicorn that got sucked up into the engine and cause "catastrophic headaches"?

 

I know, right? I've already stated in the other pre-cat detonation thread that I don't think the VVT on the VQ35s is anywhere close to what it would have to be to theoretically choke on some pre-cat dust at idle. They engineered our engine to be a daily driver, not some insane sports car with an exhaust valve that almost never closes.

Again, Child of Korn's pre-cat dumped into his main cat, which clogged, which hurt his engine until his mechanics unplugged the main cat for him.

 

wat ... who are you?

Very true, but if this were the case, then with respect to the term aggressive, in theory, Z33's would have more problems since they have more aggressive CVTC curves, as would I and other TS F-Spec owners.


The "choppy" curve is the A33B/A34 and the smooth, more advanced in the low RPM curve is the Z33/V35.

 

Does the exhaust timing follow that same curve?

...since that is what would let material into the engine. I'll freely admit that that curve doesn't mean a whole lot to me since I don't have any other values to compare it to. All VQ35s have EGR, right? Most of my reading indicated that using overly-aggressive timings to meet emissions on engines without traditional EGR systems can cause problems.

How many people got a TS flash (may they rest in peace. =( ), anyway? I wouldn't think that it is enough of a change to cause reversion on a scale large enough to do what all the "FUD" is about. But it's an interesting thought, nonetheless.

 

well just recieved my pre cat from discountcatalyticconverters.com, the only gasket I got with it was the smaller one that goes to the exhaust, so I just gave them a call and asked them about the manifold side and they said that needs to be ordered separately

you think they would have mentioned that when I ordered the cat

 

It's not variable so, no.

Most if not all TS candidates most likely have headers, so that narrows the population down further.

Or, you would have thought you would have been ready and ordered some beforehand like previously instructed.

 

I actually did pick them up a few days ago, at my local autozone, but when I got the cat today the gaskets weren't the right size, just got back from returning them, the top manifold side is a dealer item, some kind of 2 piece gasket, a mesh and a shell

just thought it was funny that they never mentioned needing a gasket, you'd think they'd try to sell you that as well when ordering the cat, oh well, just a heads up

 

Oh yeah .... IMO, OEM is the ONLY way to go for exhaust gaskets. You'd be surprised at the quality of them vs other items.

 

I installed my Eastern pre-cats front the other week without the gasket and so far the light hasn't came on since. The old gasket didn't fit the new Eastern pre-cats and their were members that stated the OEM gaskets would not fit the Eastern cats because of the "legs" on them. So far no exhaust leak or strange noises ... knock on wood

 

hmm good to know

hoping to get mine installed today, my buddy has a lift, I'll bring my camera and snap some pics

 

Hello, Well I was at the shop and was told I needed a new cat (p0420) among other things (shock and struts, tires, radiator). I have an 02 max se mt6, is this the part I need, I would hate to order the wrong thing..

http://www.proimporttuners.com/index...roducts_id=513

the rear was the one i was told i needed and dont want to pay the $650 no name produst the shop is pushing.

Also, do new headers eliminate the need for the cats all together or just one? and which one? Was told by the shop that I had to have the cats per texas law. But I know in today economy people might be willing to "fudge" the numbers a bit for their bottom line.

If not the magnaflow is there a better option? Was intrested in a cat back but i need the "cats" right? ugggg my head is spinning.

Thank You very much for your time.

 

Headers will eliminate the front pre-cats(2). The rear cat can be replaced with a stock, hi-flow, or test pipe. I'm sure you can find a shop that will install about anything you want. It's all in how you ask. Austin doesn't have emissions testing, right?

 

Williamson County does have emission testing sad to say , . I need to register my car back in temple (60 miles north) where they dont have it but its only a matter of time before they do.

Figure if i have to spend $500-$600 for a cat, just getting headers might be a better option, or the hi-flow cat. Looks like im about to start putting some money into my car.

 

I have a hi flow cat for decent price if you need it. It's for a 4th gen, but will work. It's 2.5". Also, I know a couple garages in SA that do inspections. Does it have to be inspected in Williamson?