Thanks. Let us know how it goes.

 

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:

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 video mine has reached the point it will set the code within 100-200 miles after clearing. In fact today 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

I will add this info to the begining of the thread as well to help others in the future first opening this thread.

-Jay

 

Going to order tonight or tomorrow. Think I'm going with Eastern Catalytic unless there's any other last minute helpful feedback out there...

 

I think eastern a good choice. Those are the ones I picked out when doing research earlier this year in preparation. At 148k, I'm on borrowed time. Definitely not looking forward to it. Good luck man!

 

Update on my situation. Got the new Walker cats in. Attempted to install them this weekend, the welded studs were once again welded crooked so the cats wouldn't mate up to the exhaust manifold. I decided I've had about enough of this exhaust work so I made the call to put the first pair of Walker cats back on with new gaskets and attempt a return on the replacement cats as I didn't want to break those welds and attempt to return slightly used cats. Now here's where I get lucky or lucky so far. When I bolted everything back together I took my time at each connection making sure not to tighten too much at once. As of right now I don't have the noticable exhaust leak I did between the front cats and the secondary, I could feel it with my hand previously. I also don't have water leaking from any of these joints now, except where the Y pipe joins the driver side exhaust but whatever on that as I can just reclamp that piece. No codes after my drive into work but its about 11 miles so I might need some more drive time to determine if I am error free.


While I am not happy about the way the flanges meet up between the rear of the Walker cats and the stock secondary pipes if this works in the long term I'll be happy to no have to mess with this crap again for a long time.


On to the pics.
New cats and the crooked stud welds that don't allow fittment.




Lovely quality control. Same Walker cats, same side slight differences, sorry for the crooked measuring tape.





Flanges both Walkers together to show slight bend in flange.



The thing I am not happy about, the gaskets don't allow the flanges to mate together. The OEM cat has a tappered inward flare, for lack of a better description, so that the gasket can seat and the flanges mate up together. The Walkers have a squared up edge on the flange so you get this garbage. If I develop an exhaust leak here again I am going to ditch the pipe gasket rings and go with a flat gasket like the ones on the secondary cats that connect to the Y pipe. Sh1t design Walker!

 

Yowzers. Sorry for all the troubles man. But thank you for posting for the rest of us. No Walkers for me.

 

I must have got lucky with my Walkers, they bolted in great. There is a small gap on the passenger side flanges but the gasket should take care of it.

 

Well. Pulled the trigger and ordered the Eastern Catalytic converters. I won a $250 gift card to Amazon at work. I was hoping to use it towards a Ham radio set up, but instead it covered a little over 1/2 the cost of the new cats. Now I just wait until they show and try to find the time to install them.

 

Cats showed up. I plan to install them on Friday since I have the day off. First impressions is they seem alright as far as what's aftermarket. They came with all the new studs, bolts, nuts and gaskets. Here's hoping the install goes smooth on Fri and there's no exhaust leaks or other problems.

 

Good luck on the install. PB blaster is your friend. 10mm ratcheting wrench, 14mm ratcheting wrench, 22mm open wrench, breaker bar, eye protection, and beer are also friends.

 

I wanted to get some miles on the davico I installed two weeks ago and so far so good about 500 miles on it. Fit and finish was great with no leaks or any issues. Good luck on the install.

 

Surf, can you get a better picture of the rear flange surface.

 

Will do.

Surf, out of curiosity, if these don't line up quite right is this something you intend to attack with a torch and bend correctly or would you just send it back? I'm curious because I see things haven't always lined up correctly on other people's installs, and I wonder if they'd had an exhaust shop do it the approach might have been to get out the rose bud and make things fit.

I'll Chen them with a straight edge and feeler gauges. The donut gasket should offer a little forgiveness hopefully. I'm also worried about exhaust leaks in the welds. If that happens I might just weld them up myself rather than fighting to swap them and doing it all over again 2-3 weeks down the road. We shall see. Fingers crossed. About to start working on it shortly.

 

Surf, out of curiosity, if these don't line up quite right is this something you intend to attack with a torch and bend correctly or would you just send it back? I'm curious because I see things haven't always lined up correctly on other people's installs, and I wonder if they'd had an exhaust shop do it the approach might have been to get out the rose bud and make things fit.

 

...Sounded like Paul-XYZ bought Eastern Catylitic and had codes return in 20k mi. Also saw a post by Robust saying he bought Walker and it had a bent bolt and bent flange which was an instant exhaust leak. Would like to know others experiences.

There is a lot of scattered info on here, and I'd like to create this thread to aggregate into centralized source of info for those in my situation.

I'd like to know what worked and didn't work.
-When did you replace? (xxx,xxx mi)?
After I was out of my extended warranty (100,000+ miles)


What brand?

I used Eastern Catalytic cat, and replaced all 4 cats, as well as a Dynomax catback system.


-How well did it fit? ie was it bent wrong, missing bolts etc)

It fit well, but there was some weld slag on the threads of the bolt holes on the flanges. I had to use a thread chaser to clean these up prior to install


-How many miles since you replaced?

60K miles


-Have any codes returned?

Yes, for P0430, I got this code back after 25K miles, so I added an oxygen sensor extension to "fix" this code. P0420 has come on intermittent recently (started at about 50K miles), but I have another oxygen sensor extension ready to go.


-Do you recommend, and any feedback?
No, I don't recommend Eastern Catalytic

Posted my responses in blue above

 

Did the Bosals. Fit like OEM. No Issues 8k later. Perf and mileage seem unaffected. They don't have the external shield like the others I've seen. Cant be any worse that the crap OEM ones that destroyed my original engine.

 

Thanks for all the feedback to this point everyone. I finally chose, bought, and just installed this past weekend.

-When did you replace? 11/13/16 @ 125,832
-What brand? Eastern Catalytic, both primary cats 40710 driver and 40711 passenger
-How well did it fit? Fit was 9.5/10 All hardware and gaskets were included, and no leaks after install. Passenger side downstream flange was clocked about 2-3 degrees off and made it a bit of a man handling wrestling match to get aligned but it did fit without any modification. Also I needed to clean some of the stud threads due to weld slag.
-How many miles since you replaced? only 1000 so far. Will update in the future.
-Have any codes returned? No codes. And prior to replacing, my P0430 would consistently return within 30-100 miles after clearing. I'm confident its good to go based on O2 sensor readings. See my videos below.
-Do you recommend, and any feedback? Yes, I would recommend. Fit was good, code is cleared, and judging by my O2 sensor readings as seen in the second video below, my problem is solved. This is a good mid to high end aftermarket converter at a fair price point. The fact that this converter offers 50k performance warranty vs the federal minimum 25k that most others such as Walker have is what sold me. Further, these cats has a beveled downstream flange identical to the OEM to seal tight with the donut gasket as opposed to a flat straight edge flange like Walker. Finally, these cats use threaded holes for studs identical to OEM for ease of instalation if not removing to full exhaust as opposed to Walker welding in studs requiring extra clearance to install and using bolts at the down stream flange rather than studs and nuts. Bonus: includes all new studs, nuts and gaskets which need to be purchased seperately with most other brands.

Some pics:


[URL=http://s999.photobucket.com/user/surfandsnow71113/media/8C06F7C4-BC6E-49D4-9DFC-A80F22326A3B_zpsdc9cbs8d.jpg.html]

[/URL]



Original cats showed no physical damage, luckily! Honeycomb still intact and no engine failure.





Side note: as always seems to happen with heat shield bolts, regardless of all the PB Blaster and MAP gas torch I could possibly do, 2/3 heat sheild bolts on each side snapped off. I didn't want to deal with trying to drill and tap so I said screw it and poped a little tack weld on each broken bolt spot. If I need to remove it in the future I'll just hit it with the dremmel and weld again. Hell, that's actually easier than dealing with the bolts!

Broken bolts:




Tack weld reattachments:





Diagnostic Videos of O2 sensors:


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

Before (bad fluctuating B2 O2 S2 voltage):

After (good steady B2 O2 S2 voltage):

Update 6/16/17:

The heat shield that came attached to my Eastern Catalytic replacement converter broke free of the shltty weld they made and started vibrating/rattling loudly at about 2000-2500 rpm. Thankfully I have a welder so I got into the most ackward upside down and kinked angle possible to re-weld it. Still, would suck balls if you didnt have a welder and had to remove and send it back for a replacement.

Additionally, I've now had a P0420 code set 3 times, all on long (4+ hr) drives. Which is wicked frustrating since I only had a P0430 code to begin with, but replaced both sides to be proactive. So now I feel like I might have replaced a good cat with a bad one on good faith...

 

Thanks for all the feedback to this point everyone. I finally chose, bought, and just installed this past weekend.

Dang, you got to this before me. I have had them bad for a while. I just have to pony up the cash and do this before any other toy purchase.
This will surely help me in the future.
Thanks for posting, Jay.

 

For those of you with warped flanges, I would suggest using REMFLEX exhaust gaskets
Remflex Exhaust Gaskets ALL MOPAR Universal/Mopar 2-1/2" Pipe 2 6005.
They're thick and allow for 50% crush to fill up to 1/16'' gaps.
I ended up using them on my Walker driver's side cat.

 

Wow I knew California was tough so I found this this morning.

https://ssl.arb.ca.gov/PartsSearchTool/CatalystSearchTool.aspx

Looks like there really are no aftermarket cats for the Xterra in California. I went through the years and they did show the Xterra starting in 2007 but they listed it for a 4 cyl so I am guessing that would be the Frontier.

 

A bit of an update on my Walker install. I threw a P2A03 code again about 3 days after the install. I cleared the code. Then decided to buy the driverside secondary cat, but from Eastern. Reason being is that P2A03 can be an exhaust leak between the two O2 sensors. Drove to work the rest of the week, then the following week drove from Boise to Jackson and back, without throwing the code. Coincidentally I have emissions testing that needs to be completed by the end of the month. So I am going to see if I pass, I don't see why I wouldn't as I am not throwing codes, then determine if I throw the Eastern secondary on the truck.

The Eastern product is hands down a better product. The flanges are OEM like, the welds are better, and so is the overall constructions. I would go with Eastern over Walker in the future.

 

Any run gutted one?

On my previous truck gmc canyon. A gutted the first one when its broke in weld. And it a nice little mod too on this truck with tune.

 

As an update, 1,000mi so far. No codes and O2 sensor readings look great. Happy with the Eastern Catalytic converters.

 

Surf and everyone, thanks for all this great info.

I am at 186,000 on all original cats and O2 sensors. I just started throwing the driver side cat code.

Has anyone tried the method of using citric acid and oxalic acid to remove the contaminates? Google: Reactivation of an Aged Commercial Three-Way Catalyst by Oxalic and Citric Acid Washing for the paper written on it.

Here are threads on other sites....

(All Years) Catalytic Converter Citric Acid Bath P0420 - Subaru Forester Owners Forum
https://forum.ih8mud.com/threads/cat-cleaning-citric-oxalic-acid-co-emissions.833570/

 

I just replaced my passenger side cats, I had a ignition coil pack go bad and ruin my Cat.
So I just replaced it last week with Eastern Cat, I had to send one back to Rock Auto but they got that corrected quickly.
I did not remove my heat shield, I simply took a tin snip and cut it so I could bend it back far enough to get to the bolts.
I had several companies tell me the manual called for 13 hours on the passenger side, but I could have finished it with the correct cat
in four hours. The cats themselves were only $300 for the pair and around $250 for the oxygen sensors.
Not a bad repair, don't be afraid to tackle it, I was really arguing with myself if I wanted to take it on, but once I removed one of my skid plates and the wheel well it looked fairly easy.
My code was off when I started the truck and several hundred miles later all is well.
Good luck.

 

Just found this thread, I came back to the site due to a P0420 code. Thanks for that useful OBDII video S&S!

I'm at 109,000 and just had all the spark plugs changed a few months ago when I had an ignition coil fail. Guessing the Cats also got fried due to this issue. Just ordered an OBDII so I can verify the cat performance before ordering parts. I only plan on doing the passenger side at the moment, but I'm expecting not long after I'll be getting the P0430 code as well.

Of course the code popped up 5 hours away from home and the same day my driver rear door decided it was no longer going to open due to the lazy lock mechanism....

 

I just got a P0430 at 129,000 miles. Searched for Cali compliant direct fit replacement. Stumbled across a Magnaflow 558212 and 558214. Listed for 2007 2008 2009 and 2010 Xterra. Available through Hottexhaust.com for $411 ea. Checked dealer pn's for 2006 and 2007 and they both have the same pn's. They do not list one for the 2005 or 2006 but everything I've found so far makes me think they will work for my 2006. Magnaflow has the Cali certification for these for the 2007 2008 2009 and 2010. Don't know why they skipped 2005 and 2006 other than it costs them to certify for specific vehicle/year. Anybody else ?????????

 

I'm in CA and my driver's side cat died with 130K on my 2006. I refused to pay $1,000 from dealer for new part, so I rolled the dice and bought a replacement from Napa Auto Parts in Reno for $300. Took me about 2+ hours to swap it out with minimal frustration. Cleared my Check Engine Light for about 3-4 weeks & just over 1,000 miles. Then code came back. My local mechanic thinks the non-CA cat may run at a slightly different temp, and therefore eventually threw the code. Guess I lost the gamble.