Purchased a 2001 Nissan Maxima GLE two months ago. Everything was fine when purchased, no check engine light, no problems....a week into driving in, check engine light came on and had to replace the engine which set me back $2,000........basically got ripped off.

Now, the check engine light is on again...codes

P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
P0430 - Catalyst System Efficiency Below Threshold (Bank 2)

Both codes are being shot at me....


Already went to my mechanic...told me we can try to change the O2 sensors, or we can change the cat.


MAX GODS, what do I do?

I read all the old threads, and everybody did something different.

Some people say, change it..others remove it..others leave it...others say if I leave it it will destroy my engine if it backfires or whatever...





Keep in my mind I am ULTRA-NOOB with cars, and am just slowly lurking and learning.

 

replace your precat, that is the one that usually goes bad.

I am doing the precat replacement on a 2001 max this week actually due to those codes. You can get a cheap aftermarket precat that'll be sufficient to getting rid of the check engine light.

do you have to pass emissions in your state? I'm assuming you do since you're worried about the light, but if you don't, you have other options.

 

Yeah, I think the pre-cat is done, since the CEL went on with both the 420 and 430 at the same time. Since both sensors are monitoring the same thing, it would only lead me to assume that it is shot.

I live in New-York.
http://www.nydmv.state.ny.us/broch/c-50.htm

I am not sure if I can pass the test with a cheaper aftermarket precat..

I also heard about taking the precat off and just going with a highflow exhaust?

 

the aftermarket precats will take care of the cel. I have used them before with good results and they are hundreds cheaper than oem. I just picked up a front precat for the 2001 max for $170 shipped.

You can go with a high flow exhaust but you will still need to take car of the cel, you'd need a simulator or an o2 extender.

 

This is a functional pre-cat right?
According to the codes shooting at me, replacing the precat would fix it right?

Where did you order it? Link ? please?

 

I got code P0430 and thinking about getting the pre-cat from junkyard. Is this a good idea?

 

Junkyard parts usally sit outside all day and night...I went to look at A radiator at A junkyard the other day, and the guy wanted 70 dollars for A ten year old radiator. I told him its ten years old and sits outside in the rain plus it has little rust on it. Told him 30 bucks and he said no so I left and just got A new one for 106 dollars and installed it myself. Sometimes you could get A good deal tho.
On the P0430 code, I had that code A couple of times and it goes away on its own...Seafoam does wonders lol

 

Problem is that I have both the PO420 AND PO430. Pre-cat is def done right?

Where can I order one for cheap?

 

ever think to gut them? i was gonna hold off on headers until spring

 

What does mean to gut? I am don't know much about cars besides what i have read on the forum, sorry.

Headers?

 

I would suggest to replace the cats...seeing how you just replaced an engine that could have ruined your cats it will be your best bet. after changing your cats there is a possibility you will get codes for you O2 sensors(I did anyway). Get VERY comfortable with your max(this forum has saved me hundred thus far) and changing things yourself or you will spend lots of $$$ on just labor. good luck

 

Gutting means you take the Pre Cats off and knock all the stuff out of them...so nothing can break in the future and ruin a engine and Headers and Y-pipe is replacing the piping up to your Main Cat here is a Pic to get a idea.....

 

So, that's like taking them off and cleaning the inside of them?


That long pipe is the pre-cat?

And the y looking are the y pipes?

What is the rounded pipe?

 

There is no pre cats in the system above in the picture they ate deleted, it is one front header, one rear, and the long pipe is the y-pipe, I had pictures of the stock pre cats but deleted them....those are Cattmans there are OBXs also....

 

How much did that cost you? Where can I get it?


It replaces the pre-cat and makes the check engine go away?

 

No you will get a CEL, but people use a 02stimulator to keep the light off, Headers Cattman run like 840, and OBXs like 380....in New York its just Visual and no CEL right...

 

Do you think I should change the y-pipe? The codes say I basically should right?

What do you mean NY is just visual?

 

Well I think Rochester, a guy on the forum he lives there and he has CATTMAN Y-PIPE not sure on FASTCAT aka Hi Flo Main Cat and CATTMANS 2.5 EXHAUST...

 

2 guys from the NY said no CEL and you are good, so dont know if you are looking for just a replacement or soon you might be looking to gain some HP, if your looking to gain HP go the Headers route and 02 stimulator, but just want the light gone then just get a replacement or you can do a 02stimulator by itself, what was the miles on the car by the way dont know if I asked or not...

 

What is the cheapest way to replace it and be safe with the car? That is what I want to do.

It has 96,000.

 

Two options one get replacements of the pre cats from online like Rockauto.com, carparts.com, etc. etc. Or the other is get the OBXs headers and a dual 02 sim to keep off the CEL and gain some HP and don't have to worry about the cats down the road..and both probably about the same price..

 

Which one is the pre-cat that i have to replace?

1.

2.




The second is the pre-cat right?

 

it's a two piece system. #2 picture bolts up to the front of the #1 picture. There are two pre-cats. One side bolts up to the back three cylinders, and the other bolts up to the front three cylinders at their exhaust manifolds. Here's what it looks like connected together. The picture below is the factory precat units, so it will look different than an aftermarket one.

 

^^^Godd Looking T BUUUURRRR...the 5.5 looks different than the 5th...

 

So for my two codes, 420 and 430, I just replace http://www.carpartswholesale.com/v5/...Listing+Page:2


Or do I have to get this
http://www.carpartswholesale.com/v5/...Listing+Page:1

too?

 

You would need both. Each side bolts up to the exhaust manifolds, one for each side, since it's a V-6 with 3 cylinders on each side. Remember, it's a two piece system.

Since exhaust bolts can be difficult to work with, your safe bet would to get quotes from reputable shops, on the parts and labor installed.

 

So, I can order one of each of those, and take it to the shop to have it replaced?

Sorry for the questions, I just don't want to order the wrong parts.

 

Here where I live, most shops won't install parts you buy and bring in yourself, due to the fact that they can't warranty their work, or it's against company policy, blah blah. For example, I was at a tire shop one day to have them look for a slow leak I had, and while I was there, I had asked them about an oil change since I had a few factory Nissan oil filters in the car with me. They said that they couldn't use the factory oil filter I have, and that they have to use the filters that their company buys and provides for them. Talk about bulls**t!

Most shops usually get wholesale prices on the parts they buy, so if you go in there and tell them you're on a budget and can't afford to spend alot of money, and go about it in a nice way, they will usually give you a bit of a break on the price.