Ilya wrote: ↑

Fri Aug 14, 2020 8:03 am

I'm not sure where I mentioned my cats being clogged but to my knowledge they aren't. They might not be efficient and below the 90% (or whatever that number was - someone in the other thread posted it) point, but my car runs fine. If my cats were clogged, I would expect the car to drive poorly. It runs like a raped ape. With or without the sensor.

I wasn't able to get the tread started with the 90* elbow so my guess is I need a tap to COMPLETELY get a new thread.

Re-thread Tool - https://www.amazon.com/ARES-71112-Oxyge ... B07253W495

Along with:

2x Bosch 15370 (replaces 226A0-ET000 - https://bit.ly/2DQDuaI)

I would consider replacing the pipe entirely if there was an affordable after market option. The OEM option at $1k is definitely the nuclear option.

I think this is the plan...anyone see issues with it?

I misunderstood your edit above as your secondary cats were bad...I apologize for that. I'm in the same boat as you; my cats are probably just below the 92% as well - my car runs great, no decrease in mileage or performance; just efficiency threshold. I stand by my my post about getting a tap vs a thread chaser (in your case). Since your cats are fine, repairing the threads and new sensors would be the 1st option I would try. If for some reason you can't repair the threads, then either welding a new bung or replacing that section with straight pipes would be the 2nd option. AFAIK, there are no aftermarket bolt on options for the V8...plenty for the V6. Exhaust shop would be the way to go, or DIY if you or someone you know can weld, especially if you have access to a lift. If I lived up there I would weld it for you. Deleting the secondaries is cake, as it's a straight piece of pipe on each side with no bends. That was my 1st mod, cost me $100 to have a shop do it (I don't have a lift)

So far, no codes as of today. I am not messing with the passenger side for now. I haven't had any issues with it.

Okay cool, I'll go ahead and purchase the above 3 items and hope for the best. My dad is a welder (well, actually, being an old school Eastern European immigrant he is a welder, carpenter, mason, electrician, mechanic, etc. lol - I'm only a DIY mechanic & information technology professional lol - can't do 80% of what he knows) and he's the one who has the lift so who knows, maybe that is an option.

I'll keep you guys posted sometime next week when I get everything and try to finish this up once and for all.

Good luck man, and I will update as well.

Good luck. make sure you use anti-sieze with the thread chaser

Yoda's Master wrote: ↑

Fri Aug 14, 2020 7:43 pm

Good luck. make sure you use anti-sieze with the thread chaser

I use anti-seize on every thread period hahaha. My dad puts that thing on everything like my oldest brother used to put ketchup one everything haha...habit I have too now picked up.

All done. 39 miles in, no lights and car drives/sounds great. Took all of 5 minutes to get a new thread done and I basically did 2 turns in, one turn out, 2 turns in, one turn out...90* O2 spacer went right in after that with very little struggle.

Thanks guys! I was able to hopefully stave off a ~$3k repair for $215ish ($180 for sensors and then the spacers + tool, etc.). SOLID.

Some pics:

Great job! Looks awesome.

I had the P0420 Bank 1 issue for a few years.

I purchased this came with a sensor. I bought a sensor in addition but my mechanic saw it had one so I returned it.

https://www.infinitiofwestchesterparts. ... 1CX0A.html

https://www.infinitiofwestchesterparts. ... tedProduct

Gasket for the flange.

I only bought 3 parts for this project.

I didn't have to replace anything else. Problem resolved. They did have to cut the original manifold. I did not stay to see the work in total but it was in the shop for a day.

I sent the cut in half manifold to Infiniti of Westchester. I just got the email today Infiniti accepted it and I'm getting my core charge refunded.

I did get a hefty discount on the work because they're a close friend to a friend.

I did notice based on location the parts price changes. But I've bought all of my official parts from this location great customer service! They answered all questions promptly.

Rameek7daGod wrote: ↑

Thu Aug 20, 2020 8:44 pm

I had the P0420 Bank 1 issue for a few years.

I purchased this came with a sensor. I bought a sensor in addition but my mechanic saw it had one so I returned it.

https://www.infinitiofwestchesterparts. ... 1CX0A.html

https://www.infinitiofwestchesterparts. ... tedProduct

Gasket for the flange.

I only bought 3 parts for this project.

I didn't have to replace anything else. Problem resolved. They did have to cut the original manifold. I did not stay to see the work in total but it was in the shop for a day.

I sent the cut in half manifold to Infiniti of Westchester. I just got the email today Infiniti accepted it and I'm getting my core charge refunded.

I did get a hefty discount on the work because they're a close friend to a friend.

I did notice based on location the parts price changes. But I've bought all of my official parts from this location great customer service! They answered all questions promptly.

forget OEM. I'm waiting for this ppe-engineering-headers-and-full-exhaust-t626437.html

Rameek7daGod wrote: ↑

Thu Aug 20, 2020 8:44 pm

I had the P0420 Bank 1 issue for a few years.

I purchased this came with a sensor. I bought a sensor in addition but my mechanic saw it had one so I returned it.

https://www.infinitiofwestchesterparts. ... 1CX0A.html

https://www.infinitiofwestchesterparts. ... tedProduct

Gasket for the flange.

I only bought 3 parts for this project.

I didn't have to replace anything else. Problem resolved. They did have to cut the original manifold. I did not stay to see the work in total but it was in the shop for a day.

I sent the cut in half manifold to Infiniti of Westchester. I just got the email today Infiniti accepted it and I'm getting my core charge refunded.

I did get a hefty discount on the work because they're a close friend to a friend.

I did notice based on location the parts price changes. But I've bought all of my official parts from this location great customer service! They answered all questions promptly.

Yes, we know that is the 'official' fix, but most of us don't have or don't want to spend the load of money it takes to fix this 'officially'. If I can spend $250 to fix a $2,500-3,000 issue, I'll do it all day and twice on Sunday.

Infiniti's design when it comes to some part of this car is absolutely horrible. Who's bright idea was it to put the cats in the manifold? My M35x wasn't like that to my knowledge and neither were my two Nissan Maxima's.

155 miles down, no light. I think it's officially nixed, hopefully for a few more years until I replace the car .

Inspection passed

Ilya wrote: ↑

Fri Aug 28, 2020 8:29 am

Inspection passed

Good deal! My inspection isn't due until Oct 31st so I am hoping this will work. So far I've logged about 650 miles on my extender with no issues so I am optimistic.

At 650 I'd say you're more than good lol. I did 200 before my inspection.

I'm following this, because I'm getting the same code for bank 2. I'm thinking about changing both o2 sensors before paying to replace the cats. Which 90* spacer did you use?

Big_Tone wrote: ↑

Mon Sep 07, 2020 11:13 am

I'm following this, because I'm getting the same code for bank 2. I'm thinking about changing both o2 sensors before paying to replace the cats. Which 90* spacer did you use?

These are the ones I purchased:

https://www.ebay.com/itm/90-Degree-Oxyg ... 2749.l2649

Still going strong.

Ilya wrote: ↑

Mon Sep 07, 2020 9:30 pm

Big_Tone wrote: ↑

Mon Sep 07, 2020 11:13 am

I'm following this, because I'm getting the same code for bank 2. I'm thinking about changing both o2 sensors before paying to replace the cats. Which 90* spacer did you use?

These are the ones I purchased:

https://www.ebay.com/itm/90-Degree-Oxyg ... 2749.l2649

Still going strong.

Thanks!

Just following up on this. 1kmi since the fix and still CEL free.

Ilya wrote: ↑

Mon Jan 04, 2021 2:38 pm

Just following up on this. 1kmi since the fix and still CEL free.

Curious to see if you’re still CEL free? My 2012 M56 just hit 109k got the P0420 this morning. Also is the extender any 18X1.5 O2 90* spacer?

Glml216 wrote: ↑

Sat Feb 05, 2022 7:14 am

Ilya wrote: ↑

Mon Jan 04, 2021 2:38 pm

Just following up on this. 1kmi since the fix and still CEL free.

Curious to see if you’re still CEL free? My 2012 M56 just hit 109k got the P0420 this morning. Also is the extender any 18X1.5 O2 90* spacer?

Yep! Still CEL free! I now live in FL which doesn't do inspections so if it came back I'd just ignore it but so far, hasn't even flickered . And yes, the eBay item I posted is no longer available but if I hover over the link, it states 18x1.5 so you should be good with that.

Ilya wrote: ↑

Sat Feb 05, 2022 8:31 am

Glml216 wrote: ↑

Sat Feb 05, 2022 7:14 am

Curious to see if you’re still CEL free? My 2012 M56 just hit 109k got the P0420 this morning. Also is the extender any 18X1.5 O2 90* spacer?

Yep! Still CEL free! I now live in FL which doesn't do inspections so if it came back I'd just ignore it but so far, hasn't even flickered . And yes, the eBay item I posted is no longer available but if I hover over the link, it states 18x1.5 so you should be good with that.

Thanks for the follow up! Sounds like I have hope if I add the extender, it seems pretty simple to do. We’re there any issues that popped up during the process or was it as easy as it sounds?

Glml216 wrote: ↑

Sat Feb 05, 2022 2:06 pm

Ilya wrote: ↑

Sat Feb 05, 2022 8:31 am

Yep! Still CEL free! I now live in FL which doesn't do inspections so if it came back I'd just ignore it but so far, hasn't even flickered . And yes, the eBay item I posted is no longer available but if I hover over the link, it states 18x1.5 so you should be good with that.

Thanks for the follow up! Sounds like I have hope if I add the extender, it seems pretty simple to do. We’re there any issues that popped up during the process or was it as easy as it sounds?

Only issue was the first attempt resulted in only being able to do one bank due to the design of the anti-fouler. Once I went 90*, the only other issue was my stripped thread in one of the O2 bungs...but the thread ripper or whatever sorted that and that was it. $40 and maybe 20 minutes of work (granted, at the time, I had access to my fathers lift and tools - don't have that anymore in FL ) and I saved thousands of $$$ .

Checked my mileage book, I am now at around 10kmi since the fix and CEL hasn't popped up or flickered once.

Sooo, when I posted about the P0420 before I was able to resolve it by buying a cat cleaner and I stopped buying gas that I think was causing the problem. Well, now I’m at 122k miles and it came back on today. I was going to get the 90° spacers, but the old links are either no good or the seller doesn’t have them anymore. Anyone know of another seller that does? I checked Amazon, but what came up was brass and had a smaller opening on one end.

Just be careful not to be running a dead cat. Low efficiency is one thing, failure of the honeycomb is another. Nissan/Infiniti engines are practically all Miller-cycle and will inhale the debris when a cat melts, with catastrophic results. Regardless of what the sensors read, an IR thermometer can tell you how bad they are very quickly. Get the cats lit on a decent drive and then measure the temp at the inlet and outlet just past the pipe welds. The outlet should be substantially hotter than the inlet, 100~130F on a healthy one, probably 30F even on a marginal one. If it's lower than that, you're risking your engine by screwing around with it.

VStar650CL wrote: ↑

Thu Mar 10, 2022 9:19 pm

Just be careful not to be running a dead cat. Low efficiency is one thing, failure of the honeycomb is another. Nissan/Infiniti engines are practically all Miller-cycle and will inhale the debris when a cat melts, with catastrophic results. Regardless of what the sensors read, an IR thermometer can tell you how bad they are very quickly. Get the cats lit on a decent drive and then measure the temp at the inlet and outlet just past the pipe welds. The outlet should be substantially hotter than the inlet, 100~130F on a healthy one, probably 30F even on a marginal one. If it's lower than that, you're risking your engine by screwing around with it.

This is great advice. I have an IR thermometer that needs new batteries. Will have to take a look. By inlet outlet you mean the headers by the motor basically? I should be able to see both if I pull off the engine cover? Or do I have to do it from the bottom (that may be more difficult now that I don't have a lift).

Is there any other symptoms of a failed honeycomb? Rattling/noise?

The best spots are basically on the cat surface an inch or two past where the manifold pipe enters (i.e., just beyond the flange if it has one) and an inch or two before where the pipe exits. Broken honeycombs rattle but don't necessarily mean the cat is unusable. If the rattle is in the manifold north of the cat, then it definitely needs to be replaced. If it's on the south end of the cat then it may be a structural failure and the rest of the honeycomb may still be working, so you can still test temperature.

VStar650CL wrote: ↑

Thu Mar 10, 2022 9:19 pm

Just be careful not to be running a dead cat. Low efficiency is one thing, failure of the honeycomb is another. Nissan/Infiniti engines are practically all Miller-cycle and will inhale the debris when a cat melts, with catastrophic results. Regardless of what the sensors read, an IR thermometer can tell you how bad they are very quickly. Get the cats lit on a decent drive and then measure the temp at the inlet and outlet just past the pipe welds. The outlet should be substantially hotter than the inlet, 100~130F on a healthy one, probably 30F even on a marginal one. If it's lower than that, you're risking your engine by screwing around with it.

I don't have the equipment needed to check temps. Based on my car's performance the cat doesn't appear to be dead. Car isn't running or sounding rough and my gas mileage is about what it always has been. Regarding the spacers, if I'm able to find the parts I would likely ask a mechanic to install them.

Regarding the cats, when/if they are replaced are the manifolds also replaced at the same time?

Big_Tone wrote: ↑

Fri Mar 11, 2022 1:06 pm

I don't have the equipment needed to check temps.

Harbor Freight, $25, reads to 1000F+. Walmart.com has some for $15 if you want to wait 2~3 days.
https://www.harborfreight.com/121-infra ... 63985.html

Big_Tone wrote: ↑

Fri Mar 11, 2022 1:06 pm

Regarding the cats, when/if they are replaced are the manifolds also replaced at the same time?

Don't own an M, but from what I can see in the parts drawings, it looks like both the 56 and 37 have separate manifolds and cats.

Ilya wrote: ↑

Fri Mar 11, 2022 8:53 am

By inlet outlet you mean the headers by the motor basically? I should be able to see both if I pull off the engine cover? Or do I have to do it from the bottom (that may be more difficult now that I don't have a lift).

Looking at the parts drawings, it appears it has to be from the bottom on an M. Looks like they're fully shielded too, so you'll probably need to shoot through the gap between the clamshells.

I believe the M56 cat is part of the manifold, at least that has been this community's impression...resulting in the motor needing to be pulled to swap them. Not sure if that is factual or not but that's been the thinking of this sub-forum for the past half-decade or so.