Rep Power: 0

Hello all. I have an 02 civic, with megan headers, and magnaflow cat and exhaust. I just brought it in for an emissions test and it failed the Nox ppm, badly-1026, and the max is 505.

I brought it to the dealer to get the e-test and some other parts replaced (not related) at the same time. While they didnt do any further diagnosis, they are blaming it on the cat and the header set-up. Now, the reason I didnt want them to do any more work on it was because of a money thing, and the fact that theyre dealer mechanics and wont know jack **** about aftermarket.

I did some research myself and found a few cheap things that I could replace which might be the source of the problem. First are the 02 sensors (even though theres no code or check engine light on), and second was the EGR valve. After doing some research it would seem like a no-brainer to replace IT.


Any thoughts??

 
Rep Power: 190

You might be able to take the EGR off and clean the sh*t out of it with TB/Intake Cleaner (like CRC brand, I think it's mostly Acetone). Do the same to the PCV.

Prob wouldn't hurt to run through a bottle of high-PEA cleaner (like Red Line SI-1 or Techron Concentrate), it may not help your emissions, but it certainly wouldn't hurt things either.

Also, make sure you drive around for a little while before the test and the car is fully warm, at least 20-30 mins of driving.

 
Rep Power: 312

It probably is your cat... I don't see what else could cause it to fail by that amount. You may need to get your hands on a non-high flow cat and install it for the emissions test. You could however try that always-pass stuff and run it on the highway to see if it helps. Otherwise your kinda screwed How old is the cat?

 
Rep Power: 293

Straight from Smogtips.com

WHAT CAUSES HIGH NO?

Nitrous Oxide or NO is created when an engine's combustion chamber temperature reaches over 2500F. Vehicle manufacturers have designed several systems, which when working properly, lower nitrous oxide emissions. Below are common failures which may cause your car, truck, van, suv, or motorhome to produce high high nitrous oxide.

1. Lean Fuel Mixture - Lean fuel mixtures cause high NOx. A lean fuel mixture exists when less fuel then required is delivered to the combustion chambers or when more air then necessary is added to the fuel. In either case the lack of gasoline needed to cool the combustion chambers down is not present. Combustion temperatures increase causing high nitrous oxide emissions. A lean fuel condition may be due to a vacuum leak/s and/or defective fuel control components, such as the Air Flow Meter, Engine Coolant Temperature Sensor, and O2 sensors.

2. Defective EGR System - The Exhaust Gas Recirculation system is designed to reduce NO. The EGR system consists of an EGR valve, EGR pressure sensor, vacuum hoses, and one or more vacuum switching valves or solenoids. Later model vehicles may be equipped with electronically controlled EGR valves, which do not require vacuum lines or switching solenoids. Electronic EGR systems will have these components built in.

The EGR system's job is to re-route a small amount of exhaust gas back into the intake manifold to help reduce combustion chamber temperatures. As mentioned above NOx is created when combustion chamber temperatures reach above 2500F.

By recirculating exhaust gas back into the intake, a small amount of the air/fuel mixture is replaced with inert gas, reducing combustion temperatures.

3. Defective Catalytic Converter (CAT) Some vehicle manufactures have designed their cars to operate without EGR valves. Non-EGR equipped vehicles rely heavily on the Catalytic Converter to assist in the reduction of NO. These vehicles have tendencies to develop CAT problems sooner then those which are equipped. If you own a non-EGR equipped vehicle, and have failed the emissions test for high NOx, pay close attention to the Catalytic Converter.

4. High Engine Mileage - Over an engine's lifetime, carbon build-up develops in the engine's combustion chambers. The more miles on your engine, the more carbon build-up on the pistons, cylinder heads and valves. Carbon build-up decreases the available space for the air/fuel mixture to combust, and causes higher cylinder compression. High compression results in high temperatures and high NOx. Keep in mind this problem is usually seen in vehicles with over 150,000 miles which have been poorly maintained. The solution to this problem is called De-Carbonizing. It usually costs around two labor hours at a smog check repair station. It will remove a good amount of carbon out of an engine. This will increase combustion space, lower compression and lower NOx.

5. Engine Overheating - Inadequate engine cooling can will high NOx. If your vehicle's cooling system is not working efficiently, (i.e. bad radiator, thermostat, hoses) high NOx will be created. Remember high NOx nitrous oxide is created when an engine's combustion chamber temperatures reach over 2500F. You will want to make sure your vehicle's cooling system is working properly, and your vehicle's temperature gauge is always indicating normal.

 
Rep Power: 284

High flow cats don't work very well, I suspect that's the true route of your problem.

I would clean the EGR valve with throttle body cleaner, like suggested earlier in this thread. The gasket is a crush type, so it's a good idea to replace it since you might have trouble getting a good seal once it's been removed.

The "always pass" stuff is usually methanol based, I think you can add up to a gallon of straight methanol with no issues to a fuel gas tank and it will burn extremely clean helping you to pass the test.

 
Rep Power: 233

https://www.civicforums.com/forums/2...on-w-pics.html

 
Rep Power: 811

stick with oem cat. its expensive for a reason because the aftermarket versions have nowhere near the precious metal content and almost dont do anything at all. companies market these as "hi flow" when in reality they are just "cheaply made" and a way to sell something thats basically a straight pipe. believe me oem cats are more than hi flow if they are being put on 500+hp cars. im sure the 90hp of the civic will not be bothered.

 
Rep Power: 0

Yeah my cat's not even a year old, I have probably only put 10 000 k on it. My car was sitting for a few months, and I did everything I could to preserve it. Im currently running fuel injector cleaner through the system and if after the 02's and EGR is replaced it doesnt work, I'll just get an under the table test. I dont have the money to **** around with the exhaust anymore, let alone the headache of doing it.

 
Rep Power: 312

This will in no way help you pass your smog test in Canada You can pass the test with your check engine light on because they actually measure emissions.

 
Rep Power: 233

Really? Here they just hook up to the OBD port and $45 later you're driving out of there with an inspection.

 
Rep Power: 312

No .. I wish.. here they hook up measuring devices to your exhaust and under the hood to check for leaks.... then they hook up your gas tank cap up to the machine as well... They give you a final measurement over your overall emissions and it decides if you fail or pass.

 
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Okay well I dont know what I'm gonna do yet. My mechanic told me theres people he knows who will do an e-test for you, but will literally use another car's stats.

 
Rep Power: 284

Thats an Ontario thing, some parts of Canada don't even have emissions testing. I just get the obdII plug in every time I go.

 
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THATS INTERESTING. I just visited the megan racing website for the first time since I was lookin for headers (like two years ago), and it seems they've made some interesting updates to their website that I would have wanted to know before!

1. They have a new disclaimer on their page which exculpates them from liability with respect to emission requirements, noting their parts are for "off road use".

2. They have a new header for the 7th gen civic, which is only for dx/lx models with a different 02 sensor set up as well. I have whats now whats called the EX or si version which used to be the 01-05 civic header presumably for all models, as it was not specified.

3. F**K!!! no wonder I'm not passing emissions!

 
Rep Power: 284

Your not passing emissions because of the $150 magnaflow cat that does little or nothing, it has nothing to do with the megan racing header.

 
Rep Power: 293

I've had no issues with my Random Tech cat so far, but then again it may be one step up from the Magnaflow, cause it was nearly $400 plus I ceramic coated it, which helps to retain the heat. Whenever I failed with my Integra, my smog guy told me to run it for 1/2 hour then pull strait in for the test. Heat helps with cat, but normally that's with CO and HC. NO is normally a function of the EGR. EGRless cars use newer 3 way cats.

 
Rep Power: 312

Well... if your passing in California then it should work here as well. How long have you had the random tech?

Your header has NOTHING to do with you failing the Etest.

 
Rep Power: 0

Yeah see, my dx actually doesn't have an egr valve. Fail. Lol. And yeah it probably is the cat...I'm gonna try and find another aftermarket cat that might work.

 
Rep Power: 811

i have heard TONS of problems with aftermarket cats (yes magnaflow, random tech, etc) failing too soon or not working properly. there is a reason oems cost so much due to the higher precious metal content inside. an aftermarket may pass smog if its pretty new and the engine is in good shape. but you will still be polluting way more than a car with oem cat.