Another failed smog thread...HC and NOx

[SD_Kouki]

Bought the car two weeks ago, buyer provided a smog cert from Sept. 2012. Wasn't within 90 days so of course to register it I have to smog it. (I know, it's his responsibility to smog it before selling...) Took it in today, passed visual, EGR and Cat passed functional as well. Failed HC and NOx though.

KA24DE with 115k miles. AEM Intake with carb sticker, HKS Hi Power exhaust , Walbro 255 fp, NGK Iridium Spark Plugs and NGK wires. The cat is still on the car so I don't really know why I'm failing? Checked spark plugs, they looked good. Wiggled coolant temp sensor and there was no change in idle. Haven't taken off the EGR valve to clean it yet, was going to see if there was any other ideas before I do that bc I heard it was a PITA to do. Oil was changed 3 weeks ago I believe (according to the seller) and I was running 91 octane fuel when I went to do the smog check. Anyways, here's the results:
http://img90.imageshack.us/img90/2682/20130430171532.jpg (http://imageshack.us/photo/my-images/90/20130430171532.jpg/)

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Any ideas before I take apart my EGR?

[zerodameaon]

Change your cat out to a new one(don't buy some used shit), that should help with HC, and cleaning the EGR will help with NOX.

[soryu]

20BTDC is stock timing.
but doesn't retarding reduce emissions?
i'm also about to get smogged, dont know if i should go 18 or 20.

[zerodameaon]

20BTDC is stock timing.
but doesn't retarding reduce emissions?
i'm also about to get smogged, dont know if i should go 18 or 20.

I honestly can't remember what way makes it easier to pass. Depends on your tech, mine would not let me go anywhere past 20* even though it says something like 2*+-.

[revat619]

Change the cat to a new one. I had the same exact problem.

[SD_Kouki]

Thanks for the replies guys. So where can I get a cat from? I see a magnaflow one for like $200+ yikes!!

[zerodameaon]

Thanks for the replies guys. So where can I get a cat from? I see a magnaflow one for like $200+ yikes!!

That's a good price. OEM or OEM replacements are around 600. I have that one and I paid 170 on amazon.

[milto0n]

Do not just go out and buy a cat. First begin with the basics.
-CLEAN your egr. It may be difficult but if you can remove your egr and give it a good clean it will help a bunch
-SEAFOAM is your best friend. Get a bottle of that and let it soak in your intake mani for a while. It'll create a smoke show so plan accordingly.
-While you are at this, look everywhere for exhaust leaks. Take advantage of the smoke screen.
-Do a tune-up. You'll want to replace your spark plugs after seafoaming since it will foul them. Get all the basic stuff, cap, rotor, wires, o2 sensor.
-Run injector cleaner
-Set your timing to 20*. If memory serves right, retarding will lower NOx but raise emissions in other categories because of improper combustion (don't quote me)
-Do not return to the smog station immediately. Let the soefoam and injector cleaner clear out.
-When at the station, leave your car idling and turn the heater on full blast.
-Report back

[zerodameaon]

More then likely he is going to need a cat if it is the original one so it should be changed. But basics are implied, yet why waste your retest if the cat really is bad and have to shell out 60 bucks again. OP if you can get a tech to pretest your car after the basics(they should do it for free or really cheap) and move on accordingly.

[milto0n]

The reason I suggest not changing cat first is because I have failed with worse numbers and passed by altering the aforementioned things without changing out the cat. Seeing as your NOx is so low at the 25mph, the cat is still doing its job. In addition, if you're cat were bad, in my personal experience, all numbers would be high. I would agree, however, that a new cat would get you closer to passing simply because it is new.

HC are raw gases which is why I suggest proper ignition tune up and setting proper ignition timing.
NOx is EGR related so also inspected egr components (Rev throttle and see if egr diaphragm goes up). Get your cat nice and hot before getting it inspected.

OP I hope this all makes sense and that it helps. Best of luck.

[zerodameaon]

At the same time I had high nox at 15mph and low at 25 and after going through all the stuff like EGR etc the only thing that lowered it was a new cat, hence why I suggested cat. His EGR passes functional so unless that tube is blocked it won't be the EGR being bad. As for cat passing functional all they do is run the numbers to see if it is legal to be on that car.

[91240coupe]

Thanks for the replies guys. So where can I get a cat from? I see a magnaflow one for like $200+ yikes!!

i just got a new magnaflow cat and it is good for the money. i dont know if youre gonna switch it out for a test pipe but if you are then just get a cheaper one thats still good. i dont plan on going straight pipe... so this cat will do me good.

[yetijeff]

Double check the egr ports are clear as well. There's a write up on here somewhere. But basically there's a bunch of clean outs on ur I/m that when dirty will not allow the recirculated exhaust gas to enter the combustion chamber.