Passing Texas Emissions Help
Thread Starter
Heel & Toe
Joined: Dec 2008
Posts: 15
Likes: 0
From: Katy Texas
Passing Texas Emissions Help
How do you get the koxs (parts/mil) down enough to pass emissions. My wife has a 91' vert with the factory TPI with a free flow borla on it. I removed the pre-cat y-pipe when I installed it and installed the by-pass sensor to make the fan come on @185 deg. Now it doesn't run hot but (also new alum. rad.) but for some reason will not pass emissions. Anyone have an idea or what I can do to check the problem ?
Race Director
Joined: Aug 2006
Posts: 18,346
Likes: 1
From: D / FW
You can try some of the octane boosters from the auto parts.
I hear they work to somewhat clean up marginal readings.
The cats have to work [ chemical processes ] .
My Hot Rod had to be registered at my brothers place [ where it stays most of the time anyway ] to get around the tailpipe tasting inspection.
There should be an exemption for cars driven less than 3,000 miles a year.
A car not pollution inspected can only be operated in a pollution controlled county ten days a month.
No latitude for the car enthusiast these days.
I hear they work to somewhat clean up marginal readings.
The cats have to work [ chemical processes ] .
My Hot Rod had to be registered at my brothers place [ where it stays most of the time anyway ] to get around the tailpipe tasting inspection.
There should be an exemption for cars driven less than 3,000 miles a year.
A car not pollution inspected can only be operated in a pollution controlled county ten days a month.
No latitude for the car enthusiast these days.
Advanced
Joined: Jul 2007
Posts: 62
Likes: 0
From: Spring TX
How do you get the koxs (parts/mil) down enough to pass emissions. My wife has a 91' vert with the factory TPI with a free flow borla on it. I removed the pre-cat y-pipe when I installed it and installed the by-pass sensor to make the fan come on @185 deg. Now it doesn't run hot but (also new alum. rad.) but for some reason will not pass emissions. Anyone have an idea or what I can do to check the problem ?
I had problems due to high HC and CO (2 of my injectors were bad - replaced all 8). Do a search for Harris County and you should pick up my post.
I believe you mean NOx?
I changed out my O2, ECM, EGR, vacuum lines and all injectors (Bosch III) and went from a garage stinking/failing emissions to being told by the inspection shop it was an exceptionally clean '89. (<$500)
Race Director
Joined: May 2006
Posts: 10,691
Likes: 71
From: Phoenix Arizona
Make sure your EGR system is working, Vacuum, solenoid, etc. That's the purpose of it, to lower NOx caused by lean burn engines. As stated above, weak/dirty injectors can be a problem. Normally I'm against it, but if you are close, alcohol (less than 5%) or those pass emissions products (mostly alcohol) might put you over the top, or more correctly under the limit.
Last edited by zr1fred; Apr 25, 2009 at 09:10 AM.
Instructor
Joined: Aug 2007
Posts: 151
Likes: 0
From: Mesquite Tx
This is a very minor fix but I have passed with marginal readings after running a bottle of RXP through the tank. After that fill up and change the engine oil. Just a very small non technical answer. Sorry
Thread Starter
Heel & Toe
Joined: Dec 2008
Posts: 15
Likes: 0
From: Katy Texas
Thanks but I have done all of the above,All sensors,egr are new.It is my belief that because I cooled down the original system and put the Free-flow Borla on that the cat is not getting hot enough to bring down the knox. The only way it will pass is by (1) putting the original pre-cat y-pipe back on or (2) totally replacing the free-flow cat with a more restrictive cat. It is a 91' and hence is still under current laws in Harris (Houston)and surrounding counties.It has to be 25 years old to qualify as an Antique. I also have a 74 and do not have to mess with this problem. Thanks everyone for the help.
Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
Thanks but I have done all of the above,All sensors,egr are new.It is my belief that because I cooled down the original system and put the Free-flow Borla on that the cat is not getting hot enough to bring down the knox. The only way it will pass is by (1) putting the original pre-cat y-pipe back on or (2) totally replacing the free-flow cat with a more restrictive cat. It is a 91' and hence is still under current laws in Harris (Houston)and surrounding counties.It has to be 25 years old to qualify as an Antique. I also have a 74 and do not have to mess with this problem. Thanks everyone for the help.
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