For those curious what it looks like when you have a cat going bad. The following is an excerpt from the FSM:


DTC P0420, P0430 THREE WAY CATALYST FUNCTION
On Board Diagnosis Logic

The ECM monitors the switching frequency ratio of air fuel ratio (A/F) sensor 1 and heated oxygen sensor 2. A three way catalyst (manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase. When the frequency ratio of air fuel ratio (A/F) sensor 1 and heated oxygen sensor 2 approaches a specified limit value, the three way catalyst (manifold) malfunction is diagnosed.


This video shows my B2 O2 S2 sensor high switching frequency indicating low oxygen storage thus setting a code for cat converter efficiency below threshold. In this case bank 2 (P0430) If you watch the botom right (B2 O2S2) you will see it switching way low to high. Compare that to B1 O2S2 at the bottom left which is much more consisitant.

The typical average values should be about:
B1 O2S1 ~0.3V, B2 O2S1 ~0.6V
B1 O2S2 ~0.6-0.7V, B2 O2S2 ~0.6-0.7V

Heres the vid:

Before (bad fluctuating B2 O2 S2 voltage):

After (good steady B2 O2 S2 voltage):

Hopefully this will help others in their diagnosis and understanding of what the ECM is looking for to trigger a P0420 (Bank 1) or P0430 (Bank 2) Catalytic Converter Efficiency Below Threshold code.

FWIW, at the time of this "Before" video mine has reached the point it will set the code within 100-200 miles after clearing. In fact it set only 30 miles after I cleared it.

Something else to consider and examine: Look at your Long Term Fuel Trims. If you see one side is way low, this will indicate it is taking away fule on that side because it is running rich. And if way high its adding fuel because the enine is running lean. This indicates a problem other than just age that is causing the cat to fail. In my case both banks are the same and normal. Thus indicating the converter has simply began to fail and run out of oxygen storage. ymmv

-Jay

 

My story here:

http://www.thenewx.org/forum/11-pow...riveline/216945-installed-new-catalytic-converters-my-2012-p4x.html#post3429001

 

Subscribed.

As a California resident and owner of a 2005 Xterra with almost 123,000 miles, I am particularly interested in information regarding CARB-approved and 50-state replacement cats.

 

Sorry no long term report or fitment info but I did buy a set of davico's I'm gonna throw on as soon as I have the time, my drivers side has gone bad,hope they work out. I bought a complete set but only need the drivers so I'll be selling the passenger side it looks to have been replaced at some time.

 

I just added a reference table of part numbers and costs.

Side note: Has anyone tried Magnaflow or Evan Fisher? Looking at those two right now.

 

This will be very helpful as I am needing replacements ASAP.

 

Thanks for the input so far RANGERSTRANGE and nczo6.

Can anyone else contribute?

 

. . . Can anyone else contribute?

@Surf and Snow:

I know this doesn't help your search for the best or most cost effective replacement cats for an Oregon vehicle, but here's what I found that applies to those of us in California and N.Y.:

OEM - CARB approved - 50 State legal (and of course the most expensive)

Walker - Not Legal for Sale or Use in CA (Walker oxygen sensors are CARB approved but not Walker catalytic converters)

Eastern - Not Legal for Sale or Use in CA & NY

Davico - Not Legal for Sale or Use in CA & NY

Bosal - Not Legal for Sale or Use in CA

Magnaflow - Not Legal for Sale or Use in CA

Evan Fischer - Not Legal for Sale or Use in CA & NY

A Google search for CARB-approved or California legal catalytic converters, also searches on AutoZone.com, OReillyauto.com, and NapaOnline.com, have all turned up nothing. Thus far the only California legal cats I can find are OEM.

Sometimes I feel like telling the Kalifornia smog nazis that they can kiss my exhaust. :|

 

Thank you for the info to help others @Mr. Bills

California is always unreasonably restrictive on everything (even lawn mower gas cans). Here in Portland, OR I am subject to emissions testing requirements for vehicle registration every 2 years. Fortunately there is no visual inspection component. For pre-OBD2 (<1996) they get a sniff test, and for all 1996+ its just a scan. Monitors need to show as complete and no P codes to pass, so fortunately for me, all these aftermarket cats are viable. But your contribution is certainly helpful for all our CA and NY members.

 

I used two Walker cats (passenger side) on my 2005 Frontier and 2006 Xterra. Both purchased from Amazon.

The one that went into the 2006 Xterra fit perfectly and a few thousand miles later, code hasn't returned.

The Walker installed on the 2005 did not fit well, I had to re-weld one of the studs because it was too crooked.

I also purchased a Bosal from Amazon for the driver side on my 2005 Frontier, it was a horrible fit too. The tube was too large on both inlet and outlet.


Sent from my iPhone using Tapatalk

 

-When did you replace? (12/26/15 at about 98k miles)
-What brand? Walker
-How well did it fit? ie was it bent wrong, missing bolts etc) Fit great! bolted right up w/ no issues or leaks
....

I used Walkers for the primaries, and straight pipes to delete the secondaries. Walkers fit great, no modifications needed, Amazon with free shipping..cheap. ...

-...
-What brand? Walker
-How well did it fit? ie was it bent wrong, missing bolts etc) Sh1t fit, due to bent flanges, bent tack welded bolts (more info below)
...
-Do you recommend, and any feedback? No I don't recommend, will be contacting Walker to see if I can get replacement cats and do this sh1tshow of a replacement all over again. Both cats had bent flanges on the front of the cat and the tack welded bolts seemed welded crooked so it didn't fit to the manifold flange at all. I grabbed a BFH and knocked out one of the bolts on each cat. Surpisingly they seemed to fit despite looking bent so I carried on. When I tried to connect to the b-pipe is where things when really wrong. They simply don't mate up correctly, as the nuts were tighting down the flanges never pulled together, instead I have a gap that is about the same width at the pipe gasket. I actually broke the factory weld on the B-pipe and had to reweld that, no pics because I suck at welding but belive I have that problem fixed. I've refitted the exhaust twice now trying to get a better fit. I completely disconnected the exhaust all the way back, including the hangers. I did notice that at some point while wheeling I snapped the metal that holds the muffler's front hanger point, not sure if that is contributing to my problem but pretty confident I just got crap cats. I have a bad exhaust leak on both sides.

Sounds like Walkers are real hit or miss. Reading the couple guys who got ones that were all screwed up makes me very hesitant to go that route.

Thanks for all the feed back so far guys. Hopefully more folks will chime in. I know more than 7 members have replaced their cats...

 

Sub'd

 

The way I did it was to hollow out the primary cats and remove the secondaries. Then I had 2 high flows welded in behind the hollowed out primaries and got the rear o2 sensors relocated behind them. So far so good, but we'll have to see how it works long term. It's not been like that long enough to tell yet for sure if it's going to be a long lasting fix or not.

 

I'm experiencing the same situation, in fact I just sat down to start researching when I saw this post.
I'm wondering if I buy an aftermarket cat will it still pass the ECM diagnostics because of the parameters set up at the factory?
I would hate to spend the time and money just to have to remove them and then buy an Oem cat.
My code is 420, will I need to change both cats or just one?
Has anyone tried the cat cleaning solutions with any luck?
I hate this crap since I also have the 1446 code and have changed out the valve with no luck, I don't want to spend $200 for a vapor canister to find out it's not the problem either.
Well I guess it's time to call the guy, I do almost all my own work, but a man's got to know his limitations!

 

When I changed the one catalytic on my 2006 Xterra, the code went away and never came back. It's been a few thousand miles since.

On my 2005 Frontier, previous owner gutted all 4 cats. So I only replaced the front two, so the SES light would go away.

It's been about 1k miles and no SES light since.


Sent from my iPhone using Tapatalk

 

-When did you replace? (12/26/15 at about 98k miles)
-What brand? Walker
-How well did it fit? ie was it bent wrong, missing bolts etc) Fit great! bolted right up w/ no issues or leaks
-How many miles since you replaced? about 20k
-Have any codes returned? No
-Do you recommend, and any feedback? I used Walkers for the primaries, and straight pipes to delete the secondaries. Walkers fit great, no modifications needed, Amazon with free shipping..cheap. It's been almost a year and have thrown no codes.

*Edited, did not see the requested format before.

 

-When did you replace? (4-8-15 at about 118k miles)
-What brand? Walker
-How well did it fit? ie was it bent wrong, missing bolts etc) Fit great! bolted right up w/ no issues or leaks
-How many miles since you replaced? about 7K
-Have any codes returned? NOPE
-Do you recommend, and any feedback? I don't drive it much, I mean I've only put 7k miles on it in 18mths. The hardest part was getting the old ones out. reinstallation was very easy. And it passed emissions last month so I'm good for another 2 years.

 

-When did you replace? Oct 2016
-What brand? Walker
-How well did it fit? ie was it bent wrong, missing bolts etc) Sh1t fit, due to bent flanges, bent tack welded bolts (more info below)
-How many miles since you replaced? about 250
-Have any codes returned? Yes, got a P2A03 due to exhaust leak
-Do you recommend, and any feedback? No I don't recommend, will be contacting Walker to see if I can get replacement cats and do this sh1tshow of a replacement all over again. Both cats had bent flanges on the front of the cat and the tack welded bolts seemed welded crooked so it didn't fit to the manifold flange at all. I grabbed a BFH and knocked out one of the bolts on each cat. Surpisingly they seemed to fit despite looking bent so I carried on. When I tried to connect to the b-pipe is where things when really wrong. They simply don't mate up correctly, as the nuts were tighting down the flanges never pulled together, instead I have a gap that is about the same width at the pipe gasket. I actually broke the factory weld on the B-pipe and had to reweld that, no pics because I suck at welding but belive I have that problem fixed. I've refitted the exhaust twice now trying to get a better fit. I completely disconnected the exhaust all the way back, including the hangers. I did notice that at some point while wheeling I snapped the metal that holds the muffler's front hanger point, not sure if that is contributing to my problem but pretty confident I just got crap cats. I have a bad exhaust leak on both sides.

 

What are the emissions tests like in CA? As in: what does a typical inspection look like?

As Surf mentioned - we don't get a visual inspection in OR. On top of that, only vehicles in the Portland and medford metros get deq testing anyways. The rest of the state is emissions testing free.

How does CA (and NY) enforce different standards (in practice, not in the written law) than the rest of the country?

 

Subbed. Replacing my engine this weekend and while disconnecting the header from the Cat they look very rusty and one has a hole in it. So I will be replacing them while the engine is out. I need to order them soon though!

Edit: Looks like Walker is doing a $50 off rebate mail in right now. I am going to buy them, i'll update how they install.

 

What prompted the eninge failure? What was wrong with it? Did a cat fail and get sucked in?

 

Just ordered replacement cats and will see how well Rockauto handles this situation. I couldn't deal with Walker directly, their Tech Talk support advised to get them replaced. Should have them later next week and installed the last weekend of Oct. I'll be sure to update this thread.

 

Are you getting another set of Walkers, or a different brand?(and if so which brand)

Good luck! Keep us updated.

 

I have 2 1/2" magnaflow high flow cats (one each bank) and they seem to work alright. My CEL hasn't come on, even with LT headers, least for the converters (i.e. no 0420/30) but I do have a header leak at flange and don't think my O2's are grounded properly and get an unrelated CEL's (would have to scan again for #'s). So, answered MF only because I have them and not sure what I'd get if I were in the market right now. They are not the cheapest choice, but IMO much better than the rock auto specials, let's say (get what you pay for)...I have no problem buying things from RA btw and have and do, just something like that I generally don't. Wlaker generally makes good replacement parts, quality vs cost, although they will not be like oem, unless specified and costing your firstborn nut

Aftermarket will never work as effectively as the oem's, if saving mother earth is your concern, or don't want to deviate from stock-look/position for smog purposes. They do perform better generally speaking (all vary like anything else).

 

Sounds like your magnaflows are universal fits mounted further down steam and not the magnaflow direct fits. Is that correct?

 

I'd have to look up when I replaced one of my cats.

Since I live in California the only place I could find a legal one was through the dealer.

ground was too soft to lift my truck to replace myself so I took it to a muffler shop and it cost me basically the core charge.

 

Hoping @pso and @Revolution Xer can chime in with feedback on their Eastern Catalytic converters.

Lights back for the 5th time. Coming on every 200-300mi. I need to make a choice and order up ASAP.

 

Sorry to have missed this. I haven't been on this forum for quite a few months while dealing with a job change and travel every week for a month for training with the guy I am replacing and then taking a month long vacation with the family.

I replaced the drivers side cat with an Eastern Catalytic that I purchased from Rock Auto several years ago (I don't recall when). I had a garage across the street from work replace it since I didn't have the time to deal with rusted bolts. I have run 10k's of miles with no problem.

This past summer, I had to replace the passenger side cat. I purchased another Eastern Catalytic along with the A/F and O2 sensors and had a different garage install them. It all worked fine for several months until the code, P420?, showed up. I cleared it and it showed up 500-700 miles later. The code has showed up 3 times now after driving a similar distance. I am now up to around 180000 miles, FWIW.

Neither of the garages mentioned any problems installing the parts, unlike what robust57 saw.

 

Just got my walker replacements. They look much better. I will take comparison pics as it may be a warranty battle. Hoping I can get some time under the truck tomorrow night or this weekend. Will update at that point.

 

Thanks Robust. I/we appreciate the feedback.

 

So now I'm leaning toward Eastern Catalytic. They seem to have the highest loadings of precious metals and accordingly have the longest (double) warranty on the catalyst itself. 50,000 mi vs. almost all the others at the federal minimum of 25,000mi for the catalyst itself (All are 50,000mi for body/welds/etc...) Also appears to be the most popular choice of those before me (poll). So OEM warranty 80k cost ~$570 and Eastern warranty 50k cost ~$200 then double the price to do both sides and I'm looking at ~$1200 for 80k or ~$400 for 50k. The extra 30k doesnt seem worth 3x the cost...

I've only found one negative experience and that is AZ-Ted. He had codes return after a year. BUT based upon this timeline I put together from this thread: http://www.thenewx.org/forum/11-powertrain-driveline/12752-p0430-bad-catalytic-converter.html I think that he had an another actual problem causing cat failures. I do not think it was defects by eastern catalytic. He had 2 (TWO!) OEM Nissan Driverside cats fail at about 50k both times. Thats not normal and 2 back to back screams there was a cause that was leading to failures, to me at least...

Timeline of AZ-Teds posts:

2008 OEM driver bad at 52k - Replaced with OEM under warranty
2011 2nd OEM driver bad 99k (47k since it was first replaced)
2012 Original OEM pass setting code
2013 Replaced both with Eastern Catalytic
2014 both codes back
2015 codes still – installed non-foulers to cheat codes

 

I have not installed my Eastern cats yet, so I will not be able to offer any perspective at this point.

I bought all 4 and all new o2 sensors because I don't want to be chasing codes for the next few years on my 160,000 mile X.