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P0420 code - SOS downpipes & Fabspeed Cat Back exhaust

I JUST passed emissions with my car. I haven’t had the codes return yet. As well as two other cars that have had the same issue as well. Since I put extenders on 2 other NC1’s and my own. So far so good. During the same conditions when the cars would’ve normally set the P0420 and/or P0430 codes have not happened since the installs dating from back to November 2022. I’m just giving my personal experience with the extenders so far.
Wow that's great news .
 
OK.. I'll go this route... They are the fab speed extenders right? With the small cat inside?
I decided against the fab speed extenders with the converter material for my own car. I watched the short term fuel trim on the HDS in the data list and there’s a visible delay in the response of the secondary 02 readings.

I can’t say if it would cause any issue or not but the PCM reaction off of what it’s reading “could” cause a fuel metering too rich or lean code at some point. The 2019 I installed them on hasn’t had any issues so I assume it will be ok. If anything changes I’ll be sure to post anything findings.
 
Then most likely I'll get a whole set of sos downpipes. I wanted to save the money but if u saying that it eventually going to cause problems with the fuel and possibly.... Worst case scenario, engine, then not worth risking it.
 
I don’t have enough data to say if there will or will not be any issue. The extenders are for us who already have sos converters and have the P0420 and P0430 codes for each bank converter. You may want to reread the thread. Yeyo2021
 
I have both codes unfortunately. I purchased the car back in Feb this year. When I got out of the dealership, the check engine light came on. I took the car back to the dealer and they said to me that it was the meth injectors that the car has. (mind u, I'm the 5th owner of the car and this car is all hooked up, after market vossen wheels., meth injectors, sos exhaust, etc.) they cleared the codes and then I went home. Then a week later the check engine light came back on. So I bought an OBD2 reader and showed code p0420 and p0430 along with break issue. That's when I started doing some research on the matter and stumble upon this forum. Now, I have reached to an agreement with the dealership. They going to give me some money back so that I can take it to an independent shop to fix the issue. So that's why I was wondering about the extenders. I was going with the extender fix so that I can save some money. But since you posted ur advice... I'm leaning more towards just buying the SOS downpipes with the cats. I don't want to risk damaging components or even worst, the engine.
 
I hope I am reading your posts accurately. You have SOS Downpipes, SOS Exhaust, SOS Meth injection System, and a JB4. Am I correct? Which SOS Exhaust do you have? what setting do you have the JB4 on? Is the Meth system operating correctly? What solution are you putting into the Meth tank?
Since there have been 4 previous owners, it is difficult to know when these various mods were done. You can ruin a cat by running fuel tank boosters Too often. Having said that, what is your best course of action Going forward.
How many miles on the car?
Ask a Acura Dealer to check what previous service was done on the car. They can cover up the owners names if they feel they have to.
Set the JB4 to its off mode where it does not impact engine parameters. I am not sure how you turn off the meth injection system. Take a look at the literature. Make sure you are using 91/93 octane fuel from a tier one supplier. Drive the car on the freeway or at speed for 50 miles or so to insure it is at temp and running well. Try clearing the codes and see if they stay off.
if the codes come back, you can try the extensions that others are discussing. If they work, then you have bought some time.
I have had SOS Downpipes on my 2017 for almost 12,000 miles and never an issue. My exhaust is OEM, but I doubt that it makes much of a difference.
You could purchase a new SOS downpipes and send in your old ones and have them reworked. When you get them back you can sell them as they will work on 2017-2022 NSXs. That way you will be able to drive your car during the repair process.
you can also run stock downpipes. One fellow who regularly runs the quarter mile prefers to use the JB4 with the regular downpipes. He says the Torque is better. He has some of the fastest runs.
My experience with problems on modified cars is to go back to basics and make changes slowly to identify the real issues. Make sure the 12 volt battery is in good shape as it can cause all sorts of issues.

share with the group what you learn. Take some pictures of your exhaust and the meth system, and anything else that has been modified. What is the mileage, what maintenance has been done. Waiting to hear
 
Also, I forgot to mention that the JB4 has had some firmware changes if I recall correctly. Verify your unit is current. Also get the instructions for setting up the JB4. Once you have solved the code issue then you can agin use the HB4, but start as if it is a new install. Do this with the meth kit as well.
 
The car does not come with the JB4. The meth injectors, the module by Aem is off. It was unplugged from the fuse box by the dealer when the problem showed up. So it's not working. Most likely the previous owners used the meth injectors and octane boosters. I spoke to sos and they told me that that could have been the culprit and poisoned the catted pipes. To tell you the truth not sure if the car has catted or catless downpipes. Either way it does not matter at this point since I'm going with the sos downpipes. I only use 93 octane on the car and nothing else. The car currently has 25k in the odo. I changed the cabin filters, the engine filters for K&N filters. The battery it's a new one that I bought from autozone with cost me 260..😐. Regardless of the above, the codes show up eventually. So I think are the downpipes that are causing the problem. What do u think?
 
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Great, thanks for the pics and information. It is hard for me to tell whether those downpipes are stock or SOS. So, I think you are on the right track. When you get the SOS downpipes you will find out whether yours are stock or not. If they are SOS I would recommend you send them in and have them rebuilt. That way you can get back some of your money. I am assuming that SOS will give you a good price for repair. I don't know enough about the meth to know if turning it off the way the dealership did will turn it off. You can ask Chris at SOS and verify.
I will take a look at mine and see if I can see anything that will help verify.
 
Thank you. I might have to plug it back in tho because when the unplugged it from the fuse box, the radar detector that was installed in the car stopped working. On top of the SOS down pipes I'm going to get the fab speed exhaust quad tips. I think it looks better and might sound better once installed. I'll keep everyone posted.
 
Get rid of the K&N filters! Absolutely no performance gains and you will be injecting gummy oil or dirt (or both) into your engines. Nothing will improve on the performance from the factory filters.
 
Get rid of the K&N filters! Absolutely no performance gains and you will be injecting gummy oil or dirt (or both) into your engines. Nothing will improve on the performance from the factory filters.
Yes, I agree. The intake with OEM filters pulls in all the air necessary for combustion. Unless properly oiled, these filters can cause contamination. Not worth it.

Also keep in mind that the SOS Downpipes have a major impact on sound and performance as opposed to the Exhaust. Get the Exhaust that looks good to you rather than thinking there will be a sound or performance improvement. In Sport + the exhaust whether stock or aftermarket comes through the main two runners. There is really no balancing or tuning that occurs in my opinion. What you have now is probably 18 lbs savings over stock. What you have is basically a straight cat back exhaust without any baffles. It won’t get louder. Where as the SOS downpipes allow 100% more throughput of air over OEM.

On the meth, rather then pull the fuse, as I stated read the instructions and turn it off if that is possible.
 
Yes, I agree. The intake with OEM filters pulls in all the air necessary for combustion. Unless properly oiled, these filters can cause contamination. Not worth it.

Also keep in mind that the SOS Downpipes have a major impact on sound and performance as opposed to the Exhaust. Get the Exhaust that looks good to you rather than thinking there will be a sound or performance improvement. In Sport + the exhaust whether stock or aftermarket comes through the main two runners. There is really no balancing or tuning that occurs in my opinion. What you have now is probably 18 lbs savings over stock. What you have is basically a straight cat back exhaust without any baffles. It won’t get louder. Where as the SOS downpipes allow 100% more throughput of air over OEM.

On the meth, rather then pull the fuse, as I stated read the instructions and turn it off if that is possible.
OK will follow all your advice. Tha k you so much guys. Will start working on this asap. Yeah the 2 tip exhaust looks OK but I would like to see the car with quad tips blacked out since the car is all black. And as for the filters, good thing I kept the originals... Lol. Tha k you again. I will reconnect the Aem module and see if I can turn it off instead.
 
By the way, the SOS Meth injection system requires a 50% solution of deionized water and 100% Methanol. So hopefully that is what has been used. Tap water has minerals that could impact the spray quality.
 
Who knows. But I highly doubt an owner of a 140k plus car will use tap water. But then again.... Some people are dumb. So who knows. I took off the K&N filters and installed the stock ones already. I'm just waiting for the check to arrive and shop for the parts. Hopefully after this, the car will be back to normal.
 
I have a question to everyone here tho. Should I get the JB4 module in the future?
From what I have read, the JB4 is a way to increase HP as long as you use the appropriate octane fuel. The Meth unit you have is suppose to help make the max HP using 91/93 octane with the JB4. So almost 100 HP more.

Frankly I don’t drive my car that hard. It has so much more power then my 2001 supercharged NSX. The NC1 is a Supercar as is. Having said that it seems many want all the power they can get. Each to their own. I have not heard anyone complain of engine damage yet.
 
The mod bug kinda supersedes what is deemed sufficient. I'm perfectly fine with stock...If I want spicy I use track mode..
 
OK. Thx for the info. One more thing. This question is more for looks. So the windshield of my car has so many chips that is really distracting when driving on the day time or in the afternoon. Now I've been looking for a new windshield repair. I was going to use safelite... But then I found out that they don't use OEM glass. The windshield is about 2k.... My question is, should I use safelite anyways for new glass which costs 500 buckd or save up and buy the OEM one. Do you guys have any experience with their glass?
 
I would seriously doubt that Safelite (or any other windshield shop) makes a windshield for the NSX due to the very limited number of units produced. I could be wrong but I think that the only option is OEM. They may be able to source it for less $$ than you would pay at the dealer though.
 
I have used safelight a number of times in the past for several cars. They are generally very experienced. When I replaced the windshield on my 2001 NSX, I requested only an OEM windshield. They asked my insurance company who approved the request.
As stated above, with limited production, I doubt that there is an aftermarket windshield. You can ask that they verify.

Also Safelight was good about making sure they had what ever seals or other parts were needed, not just the windshield. Also they preferred that I brought the car in to their facility so that more than one person was available to remove the old and set the new one. I was very pleased. I recommend that you replace rather then live with a lot of chips in the windshield. New glass dramatically improves the driving experience.
 
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