Cannot Pass Emissions - TCCoA Forums
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post #1 of 6 (permalink) Old 05-06-2006, 09:37 AM Thread Starter
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Cannot Pass Emissions

Ok, I just took my car to the shop to get emissions and I failed. My car seems to not be burning all the gas and seems to be putting out too much NO2. Does anyone know what would help this?

I took it to the shop again to see what they could do they just ran me up a $250 bill and I still cant pass. (Normal shop not muffler shop).They said It might be the catalytic converter but they said they dont know which to look at or something. I'm trying to stay away from the muffler place cuz i have a feeling im'a spend $300-$750 that I could easily save a lot of money on. I don't want them to fix something that doesnt need to be fixed again and charge me. Anyone else had this problem?

Car: 1988 T-bird LX 3.8l

Any help would be greatly appreciated.

How much would it cost to completely replace my exhaust system? or at least a price range from about the cheapest to decent performance. I'm just trying to get it running before I do alot to it.
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post #2 of 6 (permalink) Old 05-06-2006, 10:54 AM
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Most states have a limit for the amount of money you have to spend on repairs correcting emission problems after you've failed already. By proving that you spent that certain amount of money after you've failed, you don't have to pass any more. Check with your local DOT/emmisions and ask if your county/state has such a low.
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post #3 of 6 (permalink) Old 05-06-2006, 04:27 PM
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My how times have gotten more expensive. Last time I looked (which must have been quite a few years ago), Georgia had a $250.00 threshold for a waiver... not any more: (From Georgia Clean Air Force)

And if my vehicle does not pass again?

Additional repairs and retesting may be required. You may qualify for a Repair Waiver for that registration year if you meet the following requirements:

*The costs for emissions-related repairs must meet or exceed $710*.
*This amount will be adjusted annually to reflect changes in the Consumer Price Index.
*The retested vehicle must show some improvement in all the areas it did not pass in the initial test.
*The retested vehicle must still pass the areas it passed in the initial test.

The whole B.S. can be found here:

Sorry man... I'm almost as bummed as you are. I live here too, and mine will need emissions testing until 2016. If I lived about 8 miles further south, I wouldn't have to get it done at all!

The shop charges were for replacing/fixing what on the car?

I'm not even sure if it can be done on an '88, but have you had the EEC codes pulled from the computer? The codes will help pinpoint what the problem is. Every time the check engine light comes on, it stores the actual error code in the computer. This three digit code can then be used to help diagnose the problem. To need emissions testing you've got to live in metro Atlanta, no? Call your local Advance Auto or Auto Zone and see if they'll pull the codes for you. Only takes a few minutes, and can be done right in the parking lot. It'll give you a better idea of what's actually wrong and about what it'll cost in parts to get if fixed.

Best of luck!

That is all...

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post #4 of 6 (permalink) Old 05-06-2006, 06:03 PM
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Nox is caused by the heat in the combustion chamber. It has nothing to do with not burning the fuel completely. Is the car overheating at all? Also if your car has EGR, make sure that is working correctly. If your car is not overheating and your EGR is working properly and you still don't pass, then you can try some other tricks to get it to pass, but they won't work if those other 2 things aren't working properly first. If you check it out and everything is working properly and it still doesn't pass, do the following
-Back off the timing a few degrees
-Put in a colder thermostat, the colder you go the more you will cut down nox but the more the HC and CO will go up. If HC and CO are way below the limit now, then try a 160. If HC and CO are pretty close, go for a 180.
-Get the car inspected first thing in the morning when it is still cool outside.
-Make sure there is NOTHING blocking the radiator. The more airflow you get over the rad, the cooler it will run.

Hope that helps.


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post #5 of 6 (permalink) Old 05-17-2006, 12:56 AM
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check o2 sensors. i replaced mine after failing emissions, went back for another try and passed
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post #6 of 6 (permalink) Old 05-17-2006, 09:06 AM
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I don't think they check for NO2 on the tests here, so I have never dealt with that type of failure, but here is a generalization of how high NO2 emissions can be caused:

Nitrogen Oxides in vehicles are caused by excessive combustion chamber temperatures. Some of the common causes of high NOx emissions are problems with the vehicle's Exhaust Gas Recirculation System (EGR), improper ignition timing, lean air/fuel mixture and malfunctions in systems that control engine temperature, such as the thermostat and cooling fan, and vacuum leaks. Due to the complexity of the internal combustion engine, other components may cause high NOx as well.

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