First I'll just say I'm not a car tech, so I have not familar with a lot of the terms used with emissions.

I have a '88 with no mods. I took it in to have the emissions test done here in St. Louis. My car has been running great with 137,000 miles on it, so I thought I would have no issues passing the test. Unfortuately it just barely failed. I changed the spark plugs and wires. I also put high octane fuel in it and used some fuel injection cleaner. So I took it in today and again, it failed. This time the numbers were worse.

In Missouri the standards are:
.8000 Grams/mile HC
15.0000 Grams/mile CO

My readings were the first time:
0.9453 HC
18.2570 CO

2nd time:
1.2072 HC
18.2570 CO

I'm basically at a loss on what else to do right now. Does anyone have any advice on what else to check/change? Or is there any one in St. Louis that knows a good mechanic to take it to? My plates are expired and this is the only thing keeping me from leagally driving it.

Thanks

 

whoa, your standards are weird. i'm used to PPM (parts per million). no worries.
first, dont use high octane. unless i'm wrong, that could be hurting you (unless you fail NOx).
second, how old is the cat? failing by so little, a new cat will likely pass you. around here at cheap places, a cat installed is around $115-125. fairly cheap if you ask me.
honestly, a new cat should do it unless you're running a new cat.

funny, did you fail worse with the high octane, or did you run if=t both time?

 

Try putting some denatured alcohol in your fuel (1/4 tank is where you want it to be). It could help you pass.

 

Do you have an Auto Zone there. They sell a product called Guaranteed To Pass. Try it!

 

I just had a new cat installed a few years back, so it sounds like that may not be the problem. Also it got worse after I used the higher octane fuel. I was under the asumption that higher octane fuel would help. I suppose I really need to find a rotary specialist around here.

Thought about the denatured alcohol trick, however that is going to be the last ditch effort. If something is wrong with my car I'd rather get it fixed. Although I wouldn't mind putting this car in storage and getting an RX8.

 

yes, the car isnt running as well as new. do everything except fix the problem. [sarcasm]
i understand that an old car cant be the same as a new car, but old cars can run well enough to pass. alcohol in the tank and certain products (which likely contain an alcohol) are coverups. if you wanna just try something like that, fine. if you want to actually fix the problem, then good for you.
so my first question; how old is the cat?

EDIT: okay, any idea how many miles are on the cat? it should be okay if its only a few years old.
from here on, only thing i can think to do is check sensors. are you any good at this? are you willing to do this?

 

wow, not sure on the miles on the cat. The paperwork is at my parents house. As for checking the sensors, that may be an idea. I'm not familar with working on cars past the general tune-up. I am postively sure that the O2 sensor has not been changed since I've had it (8 yrs). Question is, would that effect it enough to have readings this high? Any other sensors I should check?

Funny thing is that I had this same test done 2 yrs ago and it had no problems passing at all. In fact the tech had told me my results were one of the lowest he had on an RX7.

edit: I doubt the cat has more than 30k on it.

 

whoops, screwed up on the 2nd reading...

should be, 1.2072 HC, 22.7567 CO

 

I'd replace the O2 sensor and the cat. It should pass with a new cat.

 

I'm failing too, on hydrocarbons. My numbers on the 25mph test were 142/146.... and on 15mph test like 362/146.

My leading plugs had the trailing wire on the rear rotor.... stupid previous owner and me guessing it would be alright.

I think its my cat... if you try the guaranteed to pass stuff make sure you run through the entire tank, otherwise it will be richer. Also, don't up the octane to pass, higher octane means that its harder to burn... so go back to lower. I'm also getting an ignition amp to help it.

I hope I don't need a new Cat.... I'm also replacing the lousey 7mm plug wires.

 

Wish we only had to do 25mph and 15mph tests. Here they basically run it anywhere from idle to 60mph. Had it been based on those 2 tests I would have passed. grr.....

Basically if I replace the cat and have it professionally installed by their "approved" techs I will be able to get a wavier. If I install it or have someone else install it, nothing I spend will go towards the wavier limit. I bet their "approved" techs charge a lot more. What a rip off.

 

Probably so, but either way a new cat will fix the problem.

 

new o2 sensor

 

oh get this, I was just told by my sister who had a similar problem that if you take it to an "approved" tech, they charge $80 just to check out the car. I hate this emissions crap

 

Emissions blow, my car will no way pass emissions, but i don't have the money to fix it. Luckily my Texas tags don't expire until december

 

i'm not sure how they do your tests, but if your O2 sensor is dead, i don't believe it can go into closed loop. this may be hurting you.
a new cat may help, but it may not be the answer. those who say it "WILL" are a tad bit (a lot) optimistic in my opinion.
that sucks that they want $80 to "look over" your car. only god knows what that means. if i'm payin someone $80 to look over my car, they better damn well find something wrong.
i'm not too familiar with the EGR and ACV systems, but those may also be a factor.

 

yeah, this is esp. hard for me. I just started a new job today after being unemployed for 6 mos.

 

i've been unemployed since august of 03. i was at UNT, car died january 31st, been running almost two months. uhg. i am the bigger loser.

 

Test your O2 sensor, it's likely dying or dead.

 

a new cat will fix the problem. I did it with both my fc's in st louis. Also, if you use the never fail emissions stuff, make sure you run it all the way through and a little fuel behind it. Or you will be worse off.

 

Unless the car is yours and you have specifically worked on it and know it's present condition, do NOT make claims saying that a new cat will pass him. You don't know that. Your cars obviously had bad cats. If you have a brand spanking new cat on the car but have an improperly working air pump, you won't pass. He's only got about 30K miles on his. My GSL-SE passed at 103,000 with the original cat on it. That's the mileage of the car when I bought it and the exhaust had never been touched until I bought it.

The cat is only a part of the emissions system. You can not just throw a cat on a rotary and expect it to pass. It won't. You also need an air pump which he should still have. Actually with his numbers, he definitely has one. If the tps is out of adjustment, you will fail. Yes even with a new cat, an air pump and everyhing else working perfectly! I would check to see if it is adjusted or working properly. The O2 sensor "might" fail you.

Higher octane gasoline will only hurt your readings. However the alcohol trick will help you. It may be a little hard to find but hunt down some Ethanol. Add about 2 gallons to at least a half a tank. The car may run like crap so you might not want to fill it totally up but your emissions will go way down. You could also try similar proportions but on a much smaller scale. something just enough to get you there and back. Then refill with regular gas and go on your way.

 

thank god i live in il and they better not adopt any emisions stuff

 

I took out the O2 sensor tonight and noticed it was really dirty and clogged. I hope this will do it for me. I still have close to a full tank of mid-grade gas, but I hope that will bring down the numbers enough for me to pass. If not, I'll drive it till the tank gets close to empty and use some denatured alcohol.

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/gateway-clean-air-program-328067/

 

Yes I agree with you...but I have had 2 rx7's and both passed after installing a new cat. both on had the air pump disconnected and check engine light(unsure of code), one had a bad tps. I shouldn't have said it "will" pass but a new cat is generally the easiest and they aren't all that expensive.