Emissions
 

How do you guys pass emissions with aftermarket engine management on obd2 vehicles. Me and my brothers are working on a project car (1999 miata) and cant decide what engine management to use because going back to stock(will be a forced induction car so will require more than just swapping the ecu back) just to pass emissions is sort of a pain in the rear. We wanna use megasquirt but ive heard of a few people running a dsm ecu with dsmlink and if we can do that and still be able to pass readiness monitors that would be cool.

Unplugging 3 connectors and plugging them back in is a pain in the rear?
If that's a pain, just don't modify cars at all. Ever.

lets see, the car will be running 750cc injectors, egr delete, maf delete for speed density, and all other supporting mods, so if you are referring to plugging the stock ecu back in then that wont work because for one the car wont even run, for two if it even did it will trigger a whole bunch of cels which wont pass emissions. But thanks for the input mr. guru.

Next time you ask a stupid question or make a vague lazy post, consider what you're asking and what your post states.

You mentioned nothing of big injectors or anything else.

What you DID ask was specifically about the ecu swap, and I answered YOUR STUPID QUESTION SPECIFICALLY. As in, if you unplug the oem ecu, plug in a pnp ms and tune it, and many actually do just that, the whole ordeal of "swapping back to stock for emissions" takes all of 5 minutes to reverse. I have personally done that actually.

And I'm not even TOUCHING on the fact that you are ridiculously lazy and can search this topic and get many hits with clear answers, but you are too much of a self entitled dipsh!t n00b and think that everyone is mandated to spoon feed you or else.

You're welcome, fgt.

Drive less than 5,000 miles

whoa there calm down, no reason for that attitude it wasn't a stupid question considering that this is the miataturbo forum maybe you are intelligent enough to piece together that it would be far from stock. So much attitude behind this wall of internet, why don't you come and talk to me face to face and we will see who the self entitled dipsh i t is. To the rest of you sane people, sorry this is going to be a boosted miata with aftermarket injectors, walbro 255lph, thinking of using an hx30 turbo but currently have an evo9 turbo, custom exhaust manifold and the rest of the exhaust, flying miata clutch, and more supporting mods. The goal is to have a vehicle that can pass washington state emmisions with the least amount of hassle. So how are you guys passing emissions with your turbo miata(obd2)?

By either not living in a shitty state that enforces emissions..... OR.... by not being lazy, and keeping all stock parts to spend 3 hours or so swapping back to pass the test, then another 3 or so reversing it that night.... Basically, you take 1 day off work, one that coincides with your scheduled appt for emissions testing. Either the night before, or the morning of, switch it all back to stock... Do the test, pass the test.... drive home, swap it all back to glory.... 1 day sacrificed out of 365 isnt much to ask in order to have a properly boosted and tuned miata... just my $0.2

Thanks. its not that i'm lazy its just that if you can pass emissions without having to go back to stock then why not do it? I am a subaru tuner and pass emissions with ridiculous setups on the stock ecu just because the stock ecu can be flash tuned so I have never had to go back to stock and was trying to do the same with the miata.

I always thought it was a cardinal sin to even ask this question on an open forum. No one here knows who you are or who's reading this. Besides that, it's classically one of those "if you have to ask..." questions.

lol, is it? if so let me know so I can rephrase my question:rofl:

:laugh:

if you have to ask...

Whats so funny? you don't know who i am and i bet you wouldn't give me that attitude if you spoke to me in person. Don't you have something better to do other than flagging negative props on every one of my posts? And me trying to pass emissions on an aftermarket ecu is no worse then you going back to stock and passing.

well, you CAN pass emission on an MS if you tune it properly... It has even been done without a cat before.... the REAL question is, does your state check to see if you have a stock ECU or not? do they plug in and check the number on your ECU

All right, you guys- rinse the sand out of your vaginas. Vlad, I'm looking at you, sweetie.


There is not, so far as I am aware, anything like ROMRaider or DSMLink for the Miata platform. Consequently, setting up forced induction to pass OBD-II emissions on these cars does take a bit more work.

One popular approach is what's known as a parallel install, wherein the stock ECU remains in place and continues to drive ancillary functions such as idle, aircon, etc., while a secondary ECU such as a Megasquirt is connected to the injectors and ignition coils. This is somewhat similar to the old piggyback-style engine management systems (emanage, Xede, etc), except that neither ECU is acting as a signal modifier for the other, they're merely doing separate tasks.

Obviously this requires that you leave most of the stock hardware (EGR, MAF, Evap, etc) in place, though it's not like these things are robbing you of power.

If OBDII is mandatory, I would be fiddling around with the AEM FIC - I know it's not the best, but OBDII... blah blah blah

For actual emissions - Gesi Cat. Not cheap, but works for high power apps.

https://www.miataturbo.net/attachmen...ine=1389540007

Tuning it wouldn't be a problem but in my state they don't check if it has an aftermarket ecu, they only plug in to check for readiness monitors.

well there probably isnt anything opensource like romraider and ecuflash for it but I have read about sniper and dptune that basically flash tune the stock ecu. I just need a little more info on both. I was really hoping to run speed density, I assume that wouldn't be possible with the parallel setup?

There's some work along these lines starting to happen with the NC, but for the NB I'm still not aware of anything at all which is end-user-tuneable.

Which sucks.



Yes, an ECU like a Megasquirt could still run in speed-density mode when installed in parallel with the stock ECU. The MAF sensor would run only to the stock ECU, while the MAP sensor would run only to the aftermarket unit. Most other sensors (temp, crank, cam, etc), would be split between the two, with the MS configured to NOT supply a pullup voltage, but rather accommodate whatever pullup the stock ECU is providing.

This is by no means an easy install, and you have to really get the tune right to keep the stock ECU from throwing fuel trim codes, but it can be done. There was a time, in fact, when this was the standard method of doing MS installation on the NB; before things like alternator control and VVT were well-understood. I would imagine that the documentation is all still lying around here somewhere...

Unless you tell people where you live no one knows what your emissions requirements are. Go to google and type in your state's name and "emissions testing" and then figure out wtf you have to do. After you do that search this forum for emissions testing and read all the info that's already here.