Mods, if the topic is too touchy for public discussion, please feel free to delete.

I'm planning on firing up the VVT swap on my '94 for the first time this weekend. Unfortunately, between the time I started the swap and today, I lost my job and it looks like the next one might be in Northridge/LA. So now I have to worry about emissions testing.

Passing the sniffer should be no big deal.

Visual - I pull my RB header and buy the expensive JR one with the EO number. I pull my <250 mile FM cat and buy the Goodwin/Magnaflow one with the proper EO number. I left my evap canister in place, no issue there. I have to put my EGR back together - trouble, but feasible. Intake - I currently have the stock 94 cross-over tube with a GM IAT sensor shoved in the hole where the IAC used to connect. I simply reattach the MAF, plug it in, and stick a cone filter on the end (legal, right? Mods before MAF are OK?) or find another stock airbox.

This all supposes that the inspector doesn't catch the fact that the motor doesn't match the chassis.

How carefully are these guys checking the engine bay? Is the VVT head going to be a red flag? Will the fact that I've loomed some of my wiring in subtly non-stock wrap draw their attention?

The EGR pipe is going to be a pain in the ***. It'll have to be 94 on the header side and 01 on the intake side. I really wish I had known this might happen when I had the damn thing on the engine stand. Has anyone done/documented such a hybrid before? I suspect it'll take more than just a bit of bending.

Lots of questions in there, I'd appreciate any wisdom you're willing to share.

 

I smogged my 1.6 car with a 1.8 engine, however it was not a VVT. Smog guy couldn't tell the difference and he probably didn't care anyway.

You can legitimately pass that car...if you bring over all the emissions equipment from a VVT car. ECU, entire evap system, EGR etc. You'll get a ref sticker and your car will be smogged as a later year car. Your early evap system will not fly. Mods before MAF are not ok. Pretty much NOTHING is okay unless it has a CARB sticker or its from a later year car and comes with all the newer stuff.

Honestly I think your biggest issue is the MS3.

 

From what I've seen, if it looks OEM, they won't give a damn. All the pictures on the screen for the machine show layouts for things like stock EGR and EVAP and vacuum routing, so that needs to be correct. They will also check your timing to make sure its where its supposed to be for the test. They will even check **** like your gas cap, and yes, you can fail for a bad gas cap. 94 is OBDI right? What are you running for an ECU? This will determine where this conversation goes.

If it were me, I would try to get a stock 94 manifold and heatshield in there and then use as much of the stock intake plumbing as possible. Barring that, 01-05 exhaust manifold and heatshield. These guys get hot when they see things that are not OEM. For example:

Yes, it can be that bad. These guys don't care what paperwork you bring them. Its not worth their time to verify that whatever aftermarket parts you have are correct or installed as per whatever documentation you present. They would rather sniff your mothers 10 year old Honda Accord, collect their $50 and move on to the next car. The state is actively trying to sting these small operators using cars with aftermarket parts, so its easier for them to just send you packing and run the next car.

 

Or better yet, find some original stock parts to put in those locations.

The fewer things which look "out of place" the better. As soon as one aftermarket part shows up, even with an EO number, the level of scrutiny is going to increase.

Ideally, you want the under-hood environment to look as totally stock as possible. It's highly doubtful that any inspector will recognize the difference between an '01+ VVT engine and a '94-'97 engine, however they WILL most certainly notice a shiny aftermarket header.


Nope. Even a K&N air filter which fits in the stock housing is technically illegal (though hugely unlikely to be noticed.)

You want a stock airbox, with a stock connecting tube and a stock MAF in between them.



The only time that an inspector will ever check the numbers is if you get sent to a referee station for suspected tampering. Otherwise, they're just ticking off items on a checklist.



Very carefully, but only with an eye for things that look non-OEM. These guys aren't Miata experts, and they don't have any reference material in front of them that shows then what shape the cam cover is supposed to be or whether the cam sensor belongs on the top vs. the back.


Hard to say. I've been extremely careful to try and match the OEM wiring as closely as possible, right down to rubbing grease and dirt all over it to make it look the right age. I've not been questioned thus far on wiring.

Protip: if you have to add or change connectors, use OEM-style parts. In particular, those cheap plastic-insulated crimp connectors with red/blue/yellow barrels will draw attention.

 

Wow, thanks guys. Very informative and slightly disheartening.

In order:

Abe - no way can I run the '01 computer, too much work. It would pretty much necessitate swapping an '01 body onto my engine.

G - Running a MS3X. 94 is OBD-I, which makes passing plausible, rather than a longshot. Definitely not liking that they'll refuse to smog for crazy stuff like oil lines lying around. I did not know they had pictures of stock setups on their screen, that could be problematic.

Joe - Sounds like I need to find some stock parts. Damn. I don't have a stock cat anymore, I assume a shiny cat is less of a flag than a shiny header?

So I need to find stock pictures of the EGR vacuum routing and the placement of the solenoids/sensors, along with the evap solenoid/sensor. I have all of those parts, though they're jumbled in a box with some NB crap. I have everything, but need references on how everything should be laid out again.

Thankfully all connectors, except the GM IAT sensor, are stock.

What a pain in the ***.

Incidentally - I know the NB header won't fit an NA exhaust system, but is it possible to mix-and-match the manifold and downpipe between the two to get a header mullet that would hook up to my NB EGR and NA exhaust, while looking completely stock?

 

Its totally doable actually, its just going to take a bit more work and research.

The diagrams they have will be for emissions related things only. I know specifically that they have routing diagrams for the crankcase vent setup because I got called out on that the first time I smogged my 95. The tech was nice enough to pull me into the shop and show me what was up on the computer screen. It wasn't a big deal, its just that the Monsterflow Intake I had on the car did not have the pre throttle body vent in the same location as the stock intake tract.

Its not that you can't smog with CARB approved aftermarket parts, its just that the shiny stuff will catch their eye. With some operators this will be a problem. The last thing you want to do is stand out in a crowd, if you know what I mean.

 

Side thought:

do any of the SoCal Miata shops do arrive-and-drive type services? At least around DC (my old stomping grounds), some of the big Spec Miata shops would store your race car, bring it to the track, and depending on the agreement do services, etc.

Might be better to just track-rat this car, but I'm not really looking to add the headache of hauler/trailer/storage to my cross-country move.

 

OK, that's a slightly different story. I can, and would have to, get the emissions plumbing 100% right, though that EGR tube may be a royal bitch.

What I'm worried about is stuff "adding up", like the wiring changes. I'm using this stuff on anything where I've changed the wiring. This includes the wires to the '01 COPs, the IAC, VVT, cam, and crank sensors, as well as the long run from the MAF wire to the new IAT location. It's not stock, but it's also not electric blue silicone rice. I'll get pictures when I'm out at the garage this weekend. It sounds like your oil-lines guy would boot me for the wiring, but your second post seems to indicate that isn't universal?

There's still a bit of a "if" to this move, but it's looking highly likely, so I'm starting to fret.

The human side of this story is that I'll be moving across the country to a new job where I absolutely must knock the socks off of everybody in fairly short order. I don't want to expend the brain cycles to be worrying about getting this car through emissions, nor do I want to be wrenching in some cheap apartment complex parking lot waiting for a busybody neighbor to complain. So, I gotta get this right the first time, before I move out there, if the car is going to be registered in CA. At least I'm not stupid enough to expect it to be my daily, I'll have to buy a "real" car for that.

 

I think these would throw the biggest flag. Where will the tech hook his inductive timing light to when he goes to check the timing? He will likely know that an OBD1 car is unlikely to have COPs.

Also does your MS3 turn on the check engine light if the key is in the run position when the car is not running?

 

The VVT engine actually used sort of a hybrid CNP, not a true COP.

There are still only two coils, and it's still a wasted-spark design. Each coil sits directly stop one plug, and has a conventional plug wire which connects it to the opposite-phase plug.


If it's not already set up for this, it's easy to do. In fact, the newest build of the MS3 code actually supports the use of the CEL for bona-fide fault indication.

 

The 01 COPs aren't really COP, more like CNP, the inductive timing light should still work, but a fair point.

My MS has full control over the CEL. Right now it should be lit if the rpm are <250 or something. Will see when I fire it up this weekend.

Edit: simulpost with Joe, who has it right.