MDittz2ndGEN

Alright.

I went and had my car smogged a while ago, the emissions results were horrible.
HC was up in the 1800's, CO was at like 5.0.

I took it to AAMCO and dropped $450 to have the Intake Gasket and injector moldings replaced, that dropped HC emissions down to about 1200 and raised my gas mileage some, but my car is still running extremely rich and failing emissions dismally. WTH is going on?

When I bought the car, I was told it was streetported. There was no paperwork for that, I bought it from the 3rd owners and they said it had been done by the 2nd owner. Could this problem be the result of a bad porting job? The car doesn't run rough, it idles and revs fine. If this is a bad port job, is there anything I can do about it short of spending $2500 on a new engine?

steven38305

This must be a prob everywhere I guess. Here in Jackson Tn we don't have to do this.

DavidHolmesIII

Porting causes excessive emissions. How much depends on the size of the porting. There are a lot of "tricks" to pass temporarily, though I would recommend fixing the exhaust/emission issues. You still have the ACV/Air-Pump, cat ?

Specific Emission Info
https://www.rx7club.com/showthread.p...06#post5131106

MDittz2ndGEN

Where would I check for ACV and the Air-pump?

There's a cat on it that looks pretty damned recent, new looking welds and it's clean.

MDittz2ndGEN

Nvermind, read the emissions FAQ.

DavidHolmesIII

Good deal. I drove on expired tags for 2 years trying to pass. If you ask me the emission testing is spreading. Its only a matter of time before its required everywhere. Good new's is the courts are incredibly nice to registration delays due to emission issues. I got 6 tickets and never had to pay anything, they arnt even on my record.

I'll tell you this, If that airpump isnt working, aka; if air isnt being injected into the cat ,you WILL NOT PASS. Make sure theres a metal pipe running from the airpump to the main cat.

Good Luck, I've been there.

MDittz2ndGEN

I had my car up on a hoist to check out the underside a while ago and didn't see any small metal pipes running to the cat

There WAS a tiny little hole in the exhaust pipe right before it entered the cat. Is that where it would be? I'll try to get a picture up, but I'm out of school until monday so it'll be at least until then.

DavidHolmesIII

Nah, that was probably a leak. The intake tube sticks out of the middle of the cat. Theres a good chance it was replaced with a universal type cat at some point.(which wouldnt have an air injection inlet)

Take a look at some of the cats on this page, you'll see the intake tube.( http://rx7.com/store/rx7/fcexhaust.html#Catbacks)
You may need to upgrade the cat in order to pass. It sucks to pay so much for a cat, but the ones at rx7.com are made specifically for rotaries and will last quite a long time.

If you know anyone with fabrication skills you could always cut and bend a small air pipe and run it from the smog pump to the cat, welding it into the existing cat.
However theres a good chance that cat is a cheap replacment, not rotary specific, and if thats the case it will clog incredibly soon, if it hasnt already.

Let me know what you see.

MDittz2ndGEN

Aw Damn.



Yeah, I'm pretty certain that it was a universal cat, and I don't recall seeing a tube sticking out of the side of it like that. Would not having that air pump working properly be enough to terrorize my emissions numbers that much?


I guess I'll make replacing that a priority, I'll probably pick up

Racing Beat Street Header/Bönez Cat System - 86-91 Non-Turbo
Price: $440.00

Since I was planning on doing my exhaust anyways. Headers and Cat. Converters are both bolt in projects, right? I can do these in my school auto shop, just sucks because I wasn't planning on dropping $500 after just spending $1,000 on new wheels and audio. Thanks for the help holmes.

DavidHolmesIII

No problem. Like I said I know what a bitch it is. My numbers dropped by like 50-60%. Yeah thats a good call on the header/cat combo, thats exactly what I got. Although I havent installed the header yet. Im waiting till I decide on a cat-back system. I've heard if you run the header with the stock cat back you get that angry bee sound. Anyways, good luck.

ericgrau

iTrader: (1)

If you're running rich (if your NOx is still good) then a new cat will not save you. In fact, the rich condition will destroy your new cat over time. Either the car is poorly tuned from a problem with some stock or aftermarket system, or your air pump isn't working. The car runs somewhat rich from the factory so you need the air pump to balance it in the cat.

Yeah, the cat bolts right in. Didn't know you could bolt a cat to the RB header tho. But if someone sells them together I guess you can. Only problem is the nuts might be rusted on your current exhaust might be rusted on pretty bad. Have fun with that.

Oh, and I'd save some money and just get a downpipe and cat (keeping the stock exhaust manifold). Gains are about the same and noise is less. See RB website for more info.

DavidHolmesIII

Eric, you should read everything before posting. He has a streetport, universal cat, and no line from the airpump to the cat. Also, I've driven both combinations, header vs downpipe, and I could notice more midrange improvement with the header, although the downpipe is cheaper by far.

Rotary Noob

Okay, as a smog tech in training...and a rotary lover, I have a couple things to say.

First, how recently were your coolant temp sensors changed? Even if the motor is ported, the amount of heat that your PCM sees (ECU) will have an effect on your emissions levels. Second, do you have an air pump, and/or EGR? Third, are any of your sensors reading incorrectly? Does your MAF think that its under full load and tells the pcm to dump fuel to fix that? Are your O2 sensors good, or do they just sit at .1v and send the pcm a lean signal?

All of those could have a serious impact on your HC's and CO's.

If the place you took it to test it didnt fail it for a visual inspection, (you could look on the VIR) then you probably have both your EGR and your air pump. If you dont know, look at your intake manifold on the outside...there should be something between the 6 port actuators. The smog pump is on the lower right hand side of the vehicle when in the drivers seat. Check the belt, check the tension on the belt, remove the belt if it is there, and check the pulley. See if it actually pumps air (if you can find the Air injection tube.) It should come off the back of the pump towards the top.

If your cat doesnt have that tube hook up, that could be an issue. It will help reduce your HC and CO's because it will allow the monolith (the big honeycomb inside the cat) to heat up better, and allow both of those to oxidize. Both of those are good. The more heat your cat has, and the more HC's and CO have access to O2, the more likely you are to pass.

If you have been running rich for a while, the cat may be dead. You could have a shop test the fuel pressure though, and check the injectors, and maybe do a fuel system service for you though. First thing I would check, if all the sensors were good, is fuel pressure. If its higher than stock...that could be a big clue right there. There should be a screw to adjust that over on the same side as the air pump...but dont go playing with it. Have a shop do it.

Check all of your sensors, make sure that your air pump is hooked into the cat, and make sure that you have correct sensor values. If all of those are right, and you still have high HC's you might go around to a muffler shop and see if you can buy a used catalytic converter off of them, and have them bolt it up to the existing one...

California only states that you have to have what was there OEM, and you cant change anything without an EO number if its INSIDE the original emissions control system. If its AFTER that system, you can do whatever the hell you want.

Just a couple thoughts. If youve got questions, send me a PM, I might be able to help you out a bit.

MDittz2ndGEN

I'm bringing this post back because it's still a problem and I have updates!


The cat IS hooked up to the air pump, how would I check to see if the air pump/cat setup is working correctly?

I had a leaking air intake gasket replaced and the emissions dropped from 1800+ to 1200-1300 (HC)

I'm thinking the porting job might be bad. Can someone explain how porting would effect emissions? Why would a porting job result in rich emissions? If anything, wouldn't the added air volume make the mixture lean?

DavidHolmesIII

The longer the port, the greater the unburned hydrocarbons. This is worse at low RPM's, idle etc. If the port if large enough to cause any overlapping , that will also effect it. Primary and Exhaust porting also cause increased emissions. Since you dont have any information on your port job, its going to be hard to tell whats been affected.


1. Lean out the mixture before testing again
2. Get the cats as hot as you can, try and go @ odd time to avoid lines.
3. If its been running that rich for a while, replace cat.
4. Test ACV by referring to the FSM
http://www.cochran-racing.com/FSM/s4...SYSTEMS_NA.pdf . (@ page 4A-42)



If it is a porting issue, which is unlikely, Bonez makes a dual cat set up for the na, you can splice the air tube from the airpump into both simultaneously. Worst Case Scenario kind of thing

http://rx7.com/store/rx7/fcexhaust.html#Catbacks

MDittz2ndGEN

When you say 'Lean out the mixture' you mean 'adjust the idle mixture', right?

DavidHolmesIII

Adjusting the air/fuel ratio. I would have a shop close to the testing center do it. If you dont know what your doing you could easily lean it out too much and have serious problems. If your getting really desperate, which I bet you are by now, go ahead and try the alcohol trick.
from the FAQ.
Once you get it to pass you'll have a whole year to figure out what to do. Hopefully you would only have to do the alcohol trick once.

turbo80cid

shot me an email, I have a word doc with pictures on how to mod your ACV to pass emission test. It worked well for me.

billsandel@sbcglobal.net