OK, i did a search for this and all i came up with was people in CA talking about denatured alcohol and rolling cutoff years, and how to remove emissions equipment so now im asking.

I have an 81 12a fb thats totally stock except for electric fans from an mr2 and a 2.25" exhaust. I built the exhaust because the one in it when i got it was all rust and the cat was blown out. I live in AZ and i have no way of getting around emissions testing. Now that i've introduced the car, here's the problem:I took the car to emissions after building the exhaust with a new magnaflow cat. It failed. The numbers were: CO...76.xx, Hc...5.xx, Nox...0.81, the standards are: CO...25.00, Hc...3.00, Nox...3.50. So it failed with flying colors. I went and put new plugs in it because they were worn out, welded the air pump tube to the pipe before the cat, and then checked the timing which was dead on spec. I took out my dirty air filter and went back: CO...65.xx, Hc...5.xx, Nox...1.18.
Tried to do some research and found that 81 should have 2 cats, and i thought that must be my problem...stupid. So i added a second magnaflow cat. Went back: CO...60.xx, Hc...4.xx, Nox...0.xx.
Its idling smooth as butter right between 700 and 800, has lots of power, and runs super smooth. WTF!? The carb is totally stock, and the only thing i know about it is that the previous owner rebuilt it, and admits he was unfamiliar with the carb. Is there an adjustment for the off-idle fuel mixture? Could he have put different jets in it? I cant seem to find any useful info about these carbs, so i'm counting on you guys for that... Please help... i have no temp tags left and no other car.

 

Its possible that it has bigger jets, I've never had any problem passing NJ emissions with just one catco cat on any of my FB's.
Sorry if I missed it, but are you running the air pump and air control valve?

 

Yeah it has the air pump and valve. Maybe the valve isnt working? When should the solenoid be on? That would give me another thing to check...

 

the air pump air needs to go to the exhaust ports or what mazda calls "port air"

90% of the time the solenoids are fine, and the valve is bad. you can rebuild/shim etc to get port air for the test.

also set the idle mixture. the cats like it a tad rich of best idle.

 

Ah, the ACV, the Achilles' heel of MAZDA stock emissions. Fragile, complex, prone to failure, expensive, and for several types of builds, NLA.

 

yep to all 3. kind of a good thing you can shim it, and pass the test

 

Yep. Have to be careful with that on thermal reactor systems, though - - you can melt things if you run it too hard shimmed; TR never gets cooled!

 

cats too. pass test, unshim...

 

I would also check with your state what the repair cap is. For instance, in Georgia, if you pay an authorised mechanic over $400 to try to pass emmissions and you still can't pass, you get a free ride. Now, the $400 is kind of high. However, here in PA, there are no tail pipe tests and you sinply fail emmissions if you have a check engine light. The repair cap here for that is $150.

I would also look into that.

 

Another option, if you designate your car as a collectible in AZ and carry collectible insurance, you are exempt from emissions. I do not know what the cost of doing that is, but just wanted to make you aware...

 

Correct me if I'm wrong, but the S2 cars have two premonolith converters upstream of the cat, then a monolith converter with air injection. I believe there's more to it than just adding another cat - I think you're looking for one or two premonolith cats that live right behind the exhaust manifold. Have you thought about just shopping for a scrapped stock exhaust that's workable?

 

Not sure how strict AZ is with the visual, but I've got RB headers and just one catco cat on mine and it always goes through, no need for the original pre cats, I'd assume the 2 cats he has on there are enough, its probably something up stream giving the problem....

 

As for collector insurance, yes thats the law here in AZ, but you must keep the car garaged, and have a modern, reliable(deemed so by the adjuster/appraiser) which you keep on regular insurance as your daily driver. I have no garage and my only other car at the moment is a 58 Edsel Corsair which is midway thru a powertrain transplant so thats out. This friday i'm going out to gold canyon to buy an 85 s-10 to drive in the meantime since i cant get any more temp tags for the rx7

The AZ repeated failure law says that you must fail emissions at least 2 times, having performed repairs each time, and that once youve spent $450 on repairs and fail within 2x the limits of concentration, you can get a one time waiver. This is my goal, but im not inside the 2x limit yet.

I was talking with som friends, and it has come to attention that the air pump cat pipe needs to be routed between the cats for the second one to have enough oxygen to react, so i'll be doing that first.

What is this stuff about shimming the ACV? If someone could point me in the right direction here its definitely something i am willig to tackle. I really want to get this car though, and drive it every day again and this idea sounds promising

 

This is kinda where im at too... i know the 2 cats i have should theoretically be better than the factory ones and i'm leaning more toward the air pump system or carb tune. AZ doesnt even do a visual on jap cars most of the time cuz the guys there dont know their *** from a hole in their head, let alone what the underside of a rotary car should look like haha.

 

this is where my theory came from that i need to move the air pump injection pipe to the second cat. My first cat is about 8 inches downstream of the manifold, and the second is about 6 inches down after it. I figure if the fisrt cat is using all the o2 in the reaction process then maybe the second one really isnt doing anything so i need to add o2 post first cat.

As far as getting stock exhaust, FB's are scarce as hell in the yards around here, and most of the cars get the cats cut out before they put them out in the yard. Even if you find a car with exhaust its almost never stock anway because the cats have usually been replaced.

 

Yea I think looking at the air pump/acv and carb are your best bets, the visual here usually isn't too rough either as the car is so old most of the kids working there don't know what they are even looking at lol

 

Main reasons why most Cali boys will built 1975 and below old school cars.
1. Smog exempt-no need for bi-annual checks.
2. We dont get hazzled by anyone.
3. Every now and then, there is a rolling smog machine on the road. this is supervise by the CHP so its hard to get away from it.

 

Of course, the downside is, no RX-7 for you...

 

We´ve had the same problem here in Spain passing our ITV this year....

After one of our rallies the exhaust was so bad that we had to replace it from the Thermal Reactor to the rear muffler.

The problem is that our unit is a 79 one, and has something after the thermal reactor that it is not a cat but it´s something like that with some air injection from the airpump. Now this thing has gone, and we have a direct pipe with a presilencer and the Muffler.

Just after installing the new system we found that the smell was worst than before but the performance was so good that we didn´t care... till we came to the ITV (emissions test).

The year before the CO% was 1,5, this year was 8,5, more than twice the maximum allowed in Spain for a 79 car (4% max). So we took the car to a friend of us who is used to de-tune carbs for emissions tests. He turned one and a half to the right the mixture screw, just before the idle became unstable and took a measure again, that was enough to reduce emissions from 8,5% to 4%, just in the limit.

To go further he started to take out one by one all the air hoses that are plugged to the air filter box, for each hose that we disconnected we took a measure, and found that the Idle Compensator hose, or at least the one that I think is the Idle Compensator, for no idea of the reason gave us another 2% CO reduction....

We took the car again to the emission test, the performance was rubbish, but they gave us the approval for one more year. After that we put back one and a half turn the mixture screw to the left, and put back the idle compensator hose in his place and the car was again running full power...

Of course it´s completely illegal... but as we are no green peace fans and we only do 5.000km each year, we think we can live with that.....


Hope that helps you....

 

You ended up eliminating the heat exchanger/preheated air injection inlet and the cooling jacket air outlet for the thermal reactor. Without which, the thermal reactor basically becomes the world's heaviest exhaust manifold, and your Air Injection System goes unfed by the air pump.

79/80 exhaust/air injection system consists of:




Disconnecting the Idle Compensator from the air cleaner has the effect of making the car run substantially leaner, since it introduces additional air to the mix. That would drop your monoxide (CO) and hydrocarbons (HC) but increase your nitrous oxides (NOX) as it makes the car burn leaner and hotter.

 

Wow...that sucks. I just got my 1980 inspected here in Texas......$15.00 later and I was on the road for another year...

Bad thing is in about 2 more years we will be re-locating back to California... There is no frigging way my 1980 will pass emissions... luckily Texas has a caveat in their registration laws that will allow me to keep my Texas registration and live in California.... Yeah I will still have Texas plates, but at least it will be legal to drive in Cali...

 

the air pump air is NOT routed to the cat during the conditions in an emissions test.

from idle to about 2500rpms, the air pump air is supposed to go to the exhaust PORTS in the engine. make sure the ACV works, and you will have no problem passing smog.

i live in CA, you should see some of the crap that passes out the tailpipe with a working ACV

 

thats right. Its not good enough unless its smog exempt coz I cant keep my RX-7's stock like some people.

 

When I lived in Atlanta, I drove all night to Miami and registered my FD at my sister's place just to not have to mess with it. I also bested my best time as I did the mid-night screamer land-speed record attempt. I made it in seven hours.

 

Ok that settles a lot of my question. I dont have a FSM yet but will be getting one, and i'll make sure that my ACV is working and update after i run it through again. What is the shimming of ACV that people were mentioning earlier? If i cant get it to pass normally I'm interested in trying that.