[Neodeuccio]

Hey guys, I was wondering if anybody has ever tried using oxygen sensor spacers with cat-less DP's to avoid turning on the MIL. It would seem to me that it should work, since the spacers would slow the response of the downstream sensors and trick them into thinking the cats were still there. Any thoughts?

[nissubaru]

Originally Posted by Neodeuccio

Hey guys, I was wondering if anybody has ever tried using oxygen sensor spacers with cat-less DP's to avoid turning on the MIL. It would seem to me that it should work, since the spacers would slow the response of the downstream sensors and trick them into thinking the cats were still there. Any thoughts?

This is a trick I've seen on Subaru's and even then it wasn't suggested. I mean, if you wanna be ghetto then I guess go ahead but if you want to be an adult with a properly running car then the correct way is to turn off the emissions code that is thrown by disabling it within your tune. Look at this comment to see what I mean.

Then there's something called "dp fix" or downpipe fix that many of us use once a year when inspection is due. It does something similar to the o2 sensor spacers, essentially it hijacks the O2 sensor signal and sends it one instead that is within spec. Eliminating the O2 sensor code.

Or, just deal with the SES light and reset it manually as needed. If you have a JB4, Burger Motorsports recently eliminated the auto-code clearing which used to solve this problem so you have to go with my above suggestion

[roadkillrob]

Do a search, it was tried 10 years ago and discussion 100 times and hasn't worked once as far as I know. There are newer spacers these days that have a little mini catalyst in them to try to help, not sure if anyone ever had success with those, but the system in these cars is pretty tight in tolerance, it can't just be less than the pre cat, it looks for a very specific reduction.

[Neodeuccio]

Originally Posted by nissubaru

This is a trick I've seen on Subaru's and even then it wasn't suggested. I mean, if you wanna be ghetto then I guess go ahead but if you want to be an adult with a properly running car then the correct way is to turn off the emissions code that is thrown by disabling it within your tune. Look at this comment to see what I mean.

Then there's something called "dp fix" or downpipe fix that many of us use once a year when inspection is due. It does something similar to the o2 sensor spacers, essentially it hijacks the O2 sensor signal and sends it one instead that is within spec. Eliminating the O2 sensor code.

Or, just deal with the SES light and reset it manually as needed. If you have a JB4, Burger Motorsports recently eliminated the auto-code clearing which used to solve this problem so you have to go with my above suggestion

I've got a buddy that's done this successfully on a couple of vehicles, but nothing that was modified. I've been reading up on the DP fix, but from what I understand it isn't a year-round solution. Driving with the MIL on would make me crazy, so I'm trying to find a permanent solution that allows the use of cat-less DP's. I came across the JB4, but I also heard that they eliminated the auto-clear, so that doesn't really help.

[nissubaru]

Originally Posted by Neodeuccio

I've got a buddy that's done this successfully on a couple of vehicles, but nothing that was modified. I've been reading up on the DP fix, but from what I understand it isn't a year-round solution. Driving with the MIL on would make me crazy, so I'm trying to find a permanent solution that allows the use of cat-less DP's. I came across the JB4, but I also heard that they eliminated the auto-clear, so that doesn't really help.

I gave you one possible solution in my original post. In order to turn the check engine light off you need to disable it within the tune. It's really easy to do it, I can even assist but you would need to get me your tune I'm not an MHD guy so you would have to ask them, I think you can just use an MHD flash and turn off the check engine light that way. MHD isn't free though

Let me clarify since its a bit confusing if you aren't familiar with MHD or flashing your car. Idk if there are any free ways but with MHD you have to pay $99 to activate the Flasher Module. From here you can flash your car with a tune that has the downpipe codes turned off. You can buy MHD map packs for like $50 but I'm not sure if they turn off the code or not. I didn't go this route. I have a JB4 so I modified the free JB4 backend flash and turned off the codes manually. I then flashed it to my car using MHD.

What you probably could do is download MHD (you need a k-dcan cable + an android tablet or phone) and then back up your current tune. Take that tune onto the computer and turn off the emissions codes, then reflash it back with MHD.

I'm like 99.99% sure this will not pass emissions though if you go in to get your car inspected. I'm in PA and the rule is something like "if you have no check engine lights, you're good to go". However I don't think that's truly the case as there is something called "emissions readiness". Without these codes activated again (you would need to flash back to the original map) the car will be unable to achieve readiness.

At that point you would most likely need to buy a DP fix in order to actually set emissions readiness. These are only to be used temporarily when going in for inspection etc...driving with a dp fix 100% of the time will just make your car think it is running differently than it really is and you'll probably have weird fuel trims as a result etc...like I said, if you want your car running correctly then don't use a dp fix or an o2 sensor spacer.

With that said, if you're running downpipes are you also running a tune?

Lastly, the people who successfully use O2 sensor spacers on non-modified cars are simply tricking the ECU into not throwing a CEL. Those cars are usually pieces of shit that wouldn't pass emissions otherwise. Our cars would pass fine, we just removed the catalytic converters which is why we need to trick the emissions test every now and again.

[Neodeuccio]

nissubaru- I didn't realize the MHD could deactivate the light like the JB4 could. I'll have to look into this more.

I haven't actually succeeded in buying a 335 yet, but I have a dealer half a mile from my house with an '09 msport coming in and they know to call me as soon as it arrives. Unless there's a glaring issue with it when I go to drive it, she'll be coming home with me.

Being a supra guy, and knowing the potential that these cars have, I can't just leave well enough alone. The difference is that modding an old supra is easy, and these are a bit more complicated.

I'll do more reading on the MHD. Thanks!

[nissubaru]

Originally Posted by Neodeuccio

nissubaru- I didn't realize the MHD could deactivate the light like the JB4 could. I'll have to look into this more.

I haven't actually succeeded in buying a 335 yet, but I have a dealer half a mile from my house with an '09 msport coming in and they know to call me as soon as it arrives. Unless there's a glaring issue with it when I go to drive it, she'll be coming home with me.

Being a supra guy, and knowing the potential that these cars have, I can't just leave well enough alone. The difference is that modding an old supra is easy, and these are a bit more complicated.

I'll do more reading on the MHD. Thanks!

If MHD does suppress the light it's more along the lines of disabling the codes within the tune. JB4 previously would auto-clear the codes which is slightly different. MHD does not have that capability, you have to manually clear the codes as they are triggered. They disabled this feature on JB4 probably a year ago or so though, otherwise they probably could have faced some legal issues.

[roadkillrob]

Generally what most people do is MHD will suppress the light, so you won't get an error on the dash (unless you check the box that says you have OEM Cat's which you can do if you still have the Cats). You want the O2's to be there working as they are important for the car to run correctly and you don't want to run on a fake signal long term.

So you just do MHD and no issues, then when it comes to needing to pass emissions, you flash MHD back to stock or map 0 and you will get the o2 errors, so then you need a DPFix which will give the ECU the signal that the ECU wants to see from the rear O2's when you have no Cat's, but you want to take it back out after. If you search around, there is an old post that tells you how to wire it up with a multipole 2 position switch and then you can just turn the DP Fix on when you need it and Off when you don't and let the actual 02's send the signal.