my inspection has been out since 08/03. i recently got a ticket for it and registration (another story). i have 900 miles on a rebuilt S5 streetported motor. for a list of what all the car has, go here: https://www.rx7club.com/showthread.p...51#post3553751.
yesterday i installed my air pump, but its not hooked to anything. its just aimlessly pumping air. today i had a cat put on with a capped off nipple. i failed emissions badly (as seen below). the car ran for maybe 5 minutes before the test. it was all idling. i had the cat installed and drove around back.
the test results are pretty bad (number-wise), but i'm not sure how bad they for the given situation. my air pump is not yet hooked to the cat and i didn't warm the cat enough first (unless it warmed to operating temperature on the dyno).
i'm going to add more later if i pass or continue to fail. any helpful stories are welcome.

results:

25mph----------------------------------------15mph
2044 rpm-------------------------------------1808 rpm

-------standard----me--------------------------standard------me
HC-------127------1313---FAIL-------------------132---------1329-----FAIL
CO-------0.71-----4.21----FAIL-------------------0.73---------3.67-----FAIL
CO2------xx--------11.9------------------------------x----------12.2
O2--------xx---------4.0-------------------------------x-----------4.4
Nox------910-------104----PASS------------------1006---------76-------PASS
DILUTION-->6.0---16.11--PASS---------------->6.0---------15.87-----PASS


original thread: https://www.rx7club.com/showthread.p...51#post3553751

 

you need to hook up the air pump to the cat
I failed too and when hooked it up I passed with flying colors

 

yea, i know i need to. its on my mental 'to-do' list. what were your (fail) numbers? they're kind of an important variable. i'd like to see as many people's "before and after" numbers as possible. i'm gonna get the pump hooked up ragardless, but i was still hoping to see people's emissions test results. i'll likely keep mine on file (shoved in a corner somewhere) for future investigation.

 

I'd say you're running rich. Put in a new O2 sensor and make sure it's warmed up real good. And yea hook up the air pump too.

Good luck!

 

we're all running rich. i'm more concerned with factual numbers a cat can make. i wish i knew the numbers before the cat was installed and i had straight pipe so i could see the difference the cat made (possibly not being warmed up fully and not having air plumbed into it.
i'm not gonna worry about an O2 sensor at all. i'm not even sure what difference they make or what they really do. i thought they had something to do with closed loop. it was replaced with a cheap Bosch one for an early 90s gmc truck. i'm not paying $70-$160 for a new mazda one.

 

Yea when they do the test it's at a steady speed and the fuel goes into closed loop. If you're O2 sensor isn't working it will read rich (i.e. heavy hc)

Mine was $30 from Autozone.

 

The O2 sensor will definitely make a difference, but the fresh air supply to the cat is the big one. I was pushing 1300ppm HCs right after I swapped in my second motor. The smog guy said it must have dead apexes. I tuned it and got the number down to 1100ppm. He chided me for wasting his time with a blown engine. I found a pair of vacuum lines were reversed, preventing the air pump's output from reaching the cats and corrected them. My next test showed 2ppm at idle and 3ppm at 2400RPM. It was fun watching the smog guy. He checked twice to make sure his machine was working.

 

just for the record, my O2 sensor was replaced within a decent amount of miles ago. i've only had the car for maybe 30,000 miles. given, its not specific to the car, but it'd take a bit of persuading to get me to buy an rx7 vehicle-specific one.

thanks for the input ScrapFC, thats what i like; hard numbers. they seem so low, though, i almost wanna call you a liar. my HCs read 1300 on both speeds, so hopefully the air pump (and heating the cat before the test) will make the difference you claim.

any other stories/numbers? i love hearing facts, not theories.

 

His are that low, I've seen the papers, hey scrap, I've got a scanner...

 

Cool. I know the numbers are a little hard to believe. I've still got all the printouts from the "test" sessions and the final numbers. If you really need to see them, I'll get together with FC-Chan and get them posted...
(It's amazing what a thorough tune-up will get you...)

 

the airpump MUST be connected to the cat, without the o2 that is pumped in via the air pump the cats will not do their job. You CAN however skip the ACV and plumb a hose directly from the air pump into the cat via the split air pipe.

 

Scrap, i believe you, but i would like to see the papers so i can see all your numbers. i know a tad about emissions numbers, so i can do a bit of reasoning between them; also, i like to learn more about the subject and seeing other's results will help that.

 

Scrap!!! where's the numbers ???!?!

well, i have some bad news on my part. my shifter boot (and assembly) isnt even on my car, only one rubber piece which i can lift and see the ground. well, i looked down tonite and saw that the cat is on upside down. this means the inlet for the split air pipe tube is on the driver's side. now i'm gonna have to take it back to the guy and have him reweld it the other way around. i still need to order that stupid pipe, too. only $73.80 for a piece of bent pipe with a check valve.

 

I'll get those numbers posted as soon as I get my hands on a scanner. I've got all that stuff on file...

 

Keep in mind that pushing the air dirrectly into the cat for a prolonged period of time will melt the thing. Most people will advise you to hook it up about a block away from DEQ and then take it in.

 

as for an update:
i hooked up the air pump and failed again, but not nearly as bad. the guy was nice and let me rerun a few more times at no cost. i went and bought some RXP (what can i say, i was desperate). i also added 3.3 gallons of gas to my 1/4-2/5 full tank to dillute the premix a tad. we ran the car at least 4 times today, but these results are from JUST hooking up the air pump.

25mph----------------------------------------15mph
2065 rpm-------------------------------------1815 rpm

-------standard----me--------------------------standard------me
HC-------127-------95-----PASS-------------------132---------210------FAIL
CO-------0.71------0.18---PASS-------------------0.73--------1.96-----FAIL
CO2------xx--------12.6------------------------------x----------13.2
O2--------xx---------4.3-------------------------------x-----------0.6
Nox------910--------70----PASS------------------1006---------33-------PASS
DILUTION-->6.0---12.78--PASS---------------->6.0---------15.87-----PASS

what sucks is i would probably pass the 15mph test if he didnt have to run the car below 2500rpm, but it requires it. how many of us drive under 2000rpm? moreso, i think its with a load (similar to incline). kinda rediculous since most of us, i would think, dont run our car at 1800rpm, much less on any incline.
my car idles better with the pressure sensor vacuum tube off. i'm not sure how the ecu responds to this, but i assume it ignores the sensor as a malfunction. with the vacuum line open, the car idles pretty solid and the CO went from 1.96 to 1.06.

now i am asking what else i can do. only two ideas i have is to run the car with very little, if any, 2 stroke (premix) for the test and to hook up the s-afc (which takes a bit of time).
anybody know how much 2 stroke affects emissions? or how little premix i can run safely for a couple of miles? i could also go to the station with barely any gas, but the proper amount of 2 stroke, then fill up near the inspection station to dillute the 2 stroke. i wish i had more time, but i only have until saturday before my tickets are due (11 days from received).

 

Autozone, 15 bucks for new bosch 02.. just have to splice on your harness wire.

part number #11027

ON EDIT --- oops didnt realize I was in 2nd gen forum.. not sure if its the same part.

 

mine's relatively new... okay, maybe 30,000 miles (at absolute most). its for an early 90s chevy truck. i really dont know how O2 sensors work, so i dont know how much of a difference it'd make or what the difference is from one to another.

 

30K on an o2 is getting kind of old.. I would just pay someone to pass your car.

 

02 sensor gives the ECU a reading of voltage .81-.91 usually. When they go bad they always read lean and the computer keeps dumping more fuel trying to correct the error.

You can buy a new sensor bosch at autozone for $15-$30. Spend the money and get it replaced. Another note is cars the run rich (rx7's) kill 02 sensors faster then cars that run leaner (honda civic) actually even though I hate honda's. They run so lean they car run wideband sensors for 100k without killing them. Wideband sensors usually have alot shorter life then a normal 02.

An AFC will help you lean the car out.