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Discussion Starter #1
Alright, I've done a few weeks worth of research on the topic (and used the search function) across my.is, club Lexus, and Reddit, and I haven't been able to find a definite answer.

I'm looking to turbo my '02 IS300. I've been looking at the options between NA-T and a GTE Aristo swap, and trying to determine which fits my needs. The goal is a daily driver with around 300 - 340 HP. Trouble is, I live in Arizona and need this car to pass an OBD II emissions test every two years. Basically the test involves them plugging into the port to get the VIN and idle readings, and then they rev it to 3000 or so and hold it there for a little. They check the VIN on the car and then check the gas cap pressure. No inspections as far as I have seen.

What I'm looking to find out is; has anyone gotten either a GTE swap or an NA-T setup to pass emissions? How did you do it? Extra points if you also passed a visual, or if you didn't get rid of your downstream O2 sensors.

Like I said earlier, I've seen a lot of back and forth and anecdotes where one person says a standalone is the only way to do either, and another says you can merge the two ECUs together on the swap (whatever that means). Other people say the ECUs don't accept piggybacks and can't be flashed. So I'm looking to find out if anyone has any experience with either setup, whether you've tuned it yourself or not.
 

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That's gonna be a tough nut to crack, especially if you haven't found a recipe to follow after weeks of research.

The OBD scanners all follow an ISO communication protocol that is well documented. It would be possible to program a microcontroller (arduino would be plenty powerful for this) to respond to an OBD code scanner and "act" like a happy OEM ecu with all the readiness bits set correctly.

Not that daunting a job if the inspection station only navigates through the emissions readiness zone.

Some decent reading here on how you might go about making a "happy ecu simulator" that tells the inspectors your car is fully compliant:

https://learn.sparkfun.com/tutorials/getting-started-with-obd-ii/all
 

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I'm planning to do exactly this. I think NA-T would be your best bet and that's what I'm doing. You'd have to use o2 sims and a piggyback ecu to keep the stock ecu happy for emissions monitors and also to prevent a check engine light from the engine seeing boost. Also the fuel trims will be out of wack with the turbo. Obviously it's not going to pass visuals with the turbo on it to an honest tech.
 

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I'm planning to do exactly this. I think NA-T would be your best bet and that's what I'm doing. You'd have to use o2 sims and a piggyback ecu to keep the stock ecu happy for emissions monitors and also to prevent a check engine light from the engine seeing boost. Also the fuel trims will be out of wack with the turbo. Obviously it's not going to pass visuals with the turbo on it to an honest tech.
as vegas said. you will never pass a visual. it might be worth to call a couple local smog shops and see how they can help you.
He said that there is no visual. The way he described emissions is exactly as it is here in Georgia. The guy hooks into the OBD2 port and his computer gives a yay or a nay. He then plugs into the gas cap and the computer again gives a pass/fail.

Because of this, I know a ton of shops here locally do what they call "check engine light diagnostics" where they literally do whatever is necessary to get it to pass necessary inspection. Many of these shops that specialize in this do emissions themselves, as a one stop shop. I would call a couple of these shops and ask them their opinion. Of course, regulations can change at any time, and it can only get worse. Luckily the cars are getting old and maybe on the verge of being grandfathered in to a lesser regulatory requirements.
 

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Luckily the cars are getting old and maybe on the verge of being grandfathered in to a lesser regulatory requirements.
In many locales, they actually grant a waiver to brand new stuff - assuming that for first couple years, it's probably fine. Then after the vehicle ages, it becomes more and more suspect.

Which I hate, but I can see the logic in it - because it's pretty true, and it saves a lot of time that'd be spent testing/checking new stuff that doesn't have any issue.

Cars need to be compliant to the standards in place during their model year. While Congress could, theoretically, legislate that all cars must conform to regulations 10 years newer than their model year - it would be absolutely ridiculous and it'd never happen unless Bernie or AOC are in charge. (Maybe this is becoming reality??)

My point is that it's highly unlikely our OBD-II compliant vehicles will ever be swept under the rug and forgotten about, OR required to meet a newer regulation. By the way, our 17 year old IS300s are fully compliant with all 2019 emission control regulations.

I still think the easiest approach here would be an ECU simulator wired to the DLC3 connector that says theres no MIL, and all the emissions monitors have completed and passed.
 

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Discussion Starter #8
He said that there is no visual. The way he described emissions is exactly as it is here in Georgia. The guy hooks into the OBD2 port and his computer gives a yay or a nay. He then plugs into the gas cap and the computer again gives a pass/fail.
as vegas said. you will never pass a visual. it might be worth to call a couple local smog shops and see how they can help you.
Yeah, just to clarify, its pretty much what trowe2 said, except that we have designated ADOT testing centers that we have to use. They aren't so much shops as they are solely for the purpose of testing your emissions. But we do have some local shops that specialize in passing emissions so I'll have to check with them and see if they have any ideas.

It would be possible to program a microcontroller (arduino would be plenty powerful for this) to respond to an OBD code scanner and "act" like a happy OEM ecu with all the readiness bits set correctly.
That is actually pretty interesting. I'll have to read through that page. If I could get it tied in with the engine RPMs so it matches what the tester is doing, that might be a pretty tidy solution.

You'd have to use o2 sims and a piggyback ecu to keep the stock ecu happy for emissions monitors and also to prevent a check engine light from the engine seeing boost.
I've been hearing some conflicting info on the piggybacks. A few people seem to swear by them and others are saying that the ECU likes to revert back to its regular state. Some guys on Club Lexus said something about having to keep the thing in a learning state to avoid this since the ECU still hasn't been cracked. It sounds like you have to keep the stock ECU to at least run the gauges, AC, and cruise control though, and I definitely need AC for out here!
 

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Discussion Starter #9
as vegas said. you will never pass a visual. it might be worth to call a couple local smog shops and see how they can help you.
He said that there is no visual. The way he described emissions is exactly as it is here in Georgia. The guy hooks into the OBD2 port and his computer gives a yay or a nay. He then plugs into the gas cap and the computer again gives a pass/fail.
Yeah, that's pretty much how it goes here. No visual inspections, although we don't have any independent shops that test emissions. We have to do our testing at Arizona Department of Transportation testing stations, so unfortunately, no bribes either :frown2:

The OBD scanners all follow an ISO communication protocol that is well documented. It would be possible to program a microcontroller (arduino would be plenty powerful for this) to respond to an OBD code scanner and "act" like a happy OEM ecu with all the readiness bits set correctly.
That is a really good idea. I would just have to splice in for RPMs so it would match up with what the tester is seeing. I'm going to take a look at that site, its a really interesting and simple fix it sounds like.

You'd have to use o2 sims and a piggyback ecu to keep the stock ecu happy for emissions monitors and also to prevent a check engine light from the engine seeing boost. Also the fuel trims will be out of wack with the turbo.
I've been hearing conflicting reports on the piggybacks. Some people over on Club Lexus were saying that the IS ECU would revert to its original state and "reject" the piggyback. The only way to keep it from doing that was to keep it from going into a ready state. This whole process would have been so much easier if they had just released the VVTi GTE in Americal :laugh:
 

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Discussion Starter #9
The OBD scanners all follow an ISO communication protocol that is well documented. It would be possible to program a microcontroller (arduino would be plenty powerful for this)...
https://learn.sparkfun.com/tutorials/getting-started-with-obd-ii/all
That's definitely an idea that seems pretty straightforward to implement. The site you gave had a ton of good info in it. Definitely the way to go if I can't do this "legally" so to speak. I would definitely need to find a way to pass RPM input to the Arduino though so that when the tester revs the engine it will actually show that.

And thank you to everyone giving legitimate thought and answers in this thread. Most of the answers I've seen on similar threads have been "move to somewhere without emissions" or "use search noob".
 

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Discussion Starter #10
I'm planning to do exactly this. I think NA-T would be your best bet and that's what I'm doing. You'd have to use o2 sims and a piggyback ecu to keep the stock ecu happy for emissions monitors and also to prevent a check engine light from the engine seeing boost. Also the fuel trims will be out of wack with the turbo. Obviously it's not going to pass visuals with the turbo on it to an honest tech.
I know a lot of people swear by the O2 Sims, but could the same result be achieved by leaving the O2s in and running high flow cats? Or do you have to run a sim if you're running boost on the GE?

And as to the piggy back, I've been seeing conflicting stuff on those. Someone on club Lexus was saying that the ECU will revert and start screwing with the piggy back on a weekly basis so you have to keep the ECU from going to a ready state to fix it. I don't know if you have any more info on the piggy backs, but that would be much appreciated.

Are there any standalones that let you do OBDII output?
 

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Discussion Starter #11
as vegas said. you will never pass a visual. it might be worth to call a couple local smog shops and see how they can help you.
Luckily we don't have a visual inspection here, but we also don't have independent shops to do the emissions testing out here either. The testing is done at Arizona Department of Transportation owned and operated facilities. The just plug in an OBDII reader, test at idle, then at revs, and then the gas cap. So no bribery to get a pass unfortunately.

So I don't have to pass an inspection, but I would like to pass the OBDII plug in test and keep it as legal as possible so that I can avoid any major trouble with getting my daily registered. Just enough so they don't get suspicious.
 

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I know a lot of people swear by the O2 Sims, but could the same result be achieved by leaving the O2s in and running high flow cats? Or do you have to run a sim if you're running boost on the GE?

And as to the piggy back, I've been seeing conflicting stuff on those. Someone on club Lexus was saying that the ECU will revert and start screwing with the piggy back on a weekly basis so you have to keep the ECU from going to a ready state to fix it. I don't know if you have any more info on the piggy backs, but that would be much appreciated.

Are there any standalones that let you do OBDII output?
Mind you, I've not tried O2 sensor "anti foulers" or sims on anything newer than my 1998 Mustang Cobra, back in the day. At that time, you could simply insert some "MIL eliminators" into the harness between the ecu and the O2 sensors, and they would condition the signal to something the ecu wouldn't be angry with.

That said, 1998 was only the 2nd mandatory year of OBD-II, and the monitors were pretty crude back then. Speaking from my experience as an OBD2 calibration engineer for an OEM, I can tell you the way the ecu tests all of the emissions control equipment (these are called "monitors") have gotten extremely sophisticated. The ecu watches the sensor inputs and carefully chooses its opportunity to examine specific ones. In some cases, the ecu can purposefully skew engine fueling a little (both rich and lean), and watch for the appropriate response from the sensors. If the ecu KNOWS it has over/under fueled the engine slightly, if the sensors are working correctly, they had BETTER respond accordingly, and at the right TIME... Else something is wrong with the sensor --> and you get the MIL.

My point: It's hard to imagine a little simulator thingie that's going to create the correct O2 signals all the time to satisfy the ecu.

Recently, on ClubLexus I think, I was corresponding with a guy that a catalyst equipped turbo IS300 with a standalone in parallel with the toyota ECU. His standalone was only doing the fueling/sparking - the Toyota ecu was fully hooked up otherwise. From his description of the setup, it sure sounded to me like it oughtta pass the O2 monitors - but it didn't, and he'd been screwing with it a lot.
 

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Discussion Starter #13
Recently, on ClubLexus I think, I was corresponding with a guy that a catalyst equipped turbo IS300 with a standalone in parallel with the toyota ECU. His standalone was only doing the fueling/sparking - the Toyota ecu was fully hooked up otherwise. From his description of the setup, it sure sounded to me like it oughtta pass the O2 monitors - but it didn't, and he'd been screwing with it a lot.
Wow, it's starting to sound like cracking the OEM ECU might be an easier task than trying to make it happy with false signals and whatnot. Alright, I'll have to try out the Arduino option. That sounds like a pretty sure bet as long as I can get it to mirror the output of a stock ECU perfectly.

Actually, now that I'm thinking about it, there was a USDM Supra TT IIRC. That ECU would have OBDII and the tables to handle emissions and boost. But I believe people said there wasn't any VVTi available on those cars either so I'd have to either find a way to mesh the two ECUs, or get a non VVTi head. But that still leaves the question of failing the test because the computer picks up a different VIN than what's on the car.

It sounds like I have my options though. Thank you Hogdon Extreme. You have been a fountain of knowledge and ideas.
 

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I literally just passed smog with my o2 sims installed so....they work fine for OBD2 testing. As for the piggyback tune not staying set, it's generally because the computer reads fuel trims and makes adjustments to long term fuel trims as a result. It's very important to monitor what the stock ECU is seeing in regards to fuel trims and adjusting the piggyback to keep the trims in line with stock conditions.
 

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Kind of skimmed this thread so sorry if majority of this has been said.
IS300 ecu is complex, you cannot tune the stock ecu (like you can with an Evo ecu which is ROM). You always have to run 2 ecus to keep all the nice interior stuff working, literally everything needs the stock ecu in place. Even when you run a standalone people are utilizing the stock ecu.

If you cant get an emissions waiver, I would just start with another chassis that you dont have to take to emissions. This car is OBD2 meaning, its probably going to be a very long time before its considered emissions "exempt".
 

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Discussion Starter #19
"register" it in Maricopa (like I do) or payson where there isnt any emissions
This is your best bet
Except that I would like to avoid having to do that.

Engineering software to reprogram/tune the stock ecu is not easy lol. Thats why everyone tries to fake the signals
/s That was the joke. Again, I've been hearing some back and forth across the forums about the O2 sims. Some say they work, and others complain that they don't completely work especially with the trick lean and rich conditions the computer will run to test the downstream O2s.
 

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I've been hearing some back and forth across the forums about the O2 sims. Some say they work, and others complain that they don't completely work especially with the trick lean and rich conditions the computer will run to test the downstream O2s.
The ecu doesnt care about the rich/lean on the downstream. Only the upstream. You can leave the OE O2s for the with the car in the exhaust system upstream (and add additional O2s for your standalone). But then when you tune, your stock ecu is going to freak out about the variation from the stock parameters.

You only want an O2 sim is only after the cat. Entire idea of the O2 sim is to make the ecu think theres a cat there still. You dont want a cat because cat on a turbo car is like exhaling through a straw.
 
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