Help Me Pass CA Smog? (High nox) :(
#1
Help Me Pass CA Smog? (High nox) :(
Hi, I'm having trouble passing CA smog with high NO levels. First had car tested around in May, failed with high NO at 15 mph, passed at 25.
That test results: (Max = maximum allowed emissions)
15 MPH- FAIL
HC: 26 (55 max)
CO: 0.02 (0.5 max)
NO: 937 (437 Max)
25 MPH- PASS
HC: 14 (39 Max)
CO: 0.03 (0.48 Max)
NO: 204 (724 Max)
I had just gotten the car back then. Since then I've done all basic maintenance, I've changed all 3 O2 sensors, I've replaced the PCV hose which had a leak, and I've cleaned the EGR Valve (along with the TB, MAF, and IACV on the way, per the directions on this forum. New gaskets for all)
I failed again today, after the above listed maintenance and the 3 month difference, my new results are even worse:
15mph-FAIL
HC: 49
CO: 0.0
NO: 1751
25mph - FAIL
HC: 52
CO: 0.0
NO: 1820
Smog tech doesn't really know what could be wrong as there are no check engine codes. Things that have been suggested to me are EGR tube (which I cleaned), and the Cat, but the smog tech told me that if the Cat were bad all of my numbers should be worse, instead of just NOx.
I'm pretty clueless as to what to do, so any suggestions, ideas, help, or even just experiences in this area I'd be really grateful for.
Thanks for reading!
P.S. I've tried the "Carb Cleaner spray on intake hoses" trick to look for vacuum leaks. I didn't find any obvious ones, but I don't feel super confident in that area so who knows.
That test results: (Max = maximum allowed emissions)
15 MPH- FAIL
HC: 26 (55 max)
CO: 0.02 (0.5 max)
NO: 937 (437 Max)
25 MPH- PASS
HC: 14 (39 Max)
CO: 0.03 (0.48 Max)
NO: 204 (724 Max)
I had just gotten the car back then. Since then I've done all basic maintenance, I've changed all 3 O2 sensors, I've replaced the PCV hose which had a leak, and I've cleaned the EGR Valve (along with the TB, MAF, and IACV on the way, per the directions on this forum. New gaskets for all)
I failed again today, after the above listed maintenance and the 3 month difference, my new results are even worse:
15mph-FAIL
HC: 49
CO: 0.0
NO: 1751
25mph - FAIL
HC: 52
CO: 0.0
NO: 1820
Smog tech doesn't really know what could be wrong as there are no check engine codes. Things that have been suggested to me are EGR tube (which I cleaned), and the Cat, but the smog tech told me that if the Cat were bad all of my numbers should be worse, instead of just NOx.
I'm pretty clueless as to what to do, so any suggestions, ideas, help, or even just experiences in this area I'd be really grateful for.
Thanks for reading!
P.S. I've tried the "Carb Cleaner spray on intake hoses" trick to look for vacuum leaks. I didn't find any obvious ones, but I don't feel super confident in that area so who knows.
#2
High nox is is directly related to high combustion temps. Clean you EGR tube first off, do you have functioning EGR? Could be a cooling problem too, is your engine running hot?Running lean would do it too, but you don't have a code so I'm guessing no.
Last edited by asand1; 09-01-2010 at 08:42 PM.
#3
You can install a water vapor injection system before the throttle body. Tends to lower combustion temps and pollution.
Very cheap to make, here's a basic schematic.
http://journeytoforever.org/biofuel_...earth/me3.html
If you used a 4" pvc pipe with an endcap and topcap, a 4" diameter round airstone from petsmart you could place the airstone directly on top of a 3/4" air stream inlet pipe inserted horizontally through the base of the 4" pipe with a check valve outside the on the outer end and the inner ending in a T with hole drilled into it at base of the 4" pvc pipe. On top of that you can place set of drilled pipes as spacers to prevent the airstone from moving up under pressure. Placing your vacuum inlet at the top of the container.
That's be a touch better and safer than the mockup in the article and would provide larger amounts of water/alcohol vapor.
Been shown to work on fuel injected too.
Very cheap to make, here's a basic schematic.
http://journeytoforever.org/biofuel_...earth/me3.html
If you used a 4" pvc pipe with an endcap and topcap, a 4" diameter round airstone from petsmart you could place the airstone directly on top of a 3/4" air stream inlet pipe inserted horizontally through the base of the 4" pipe with a check valve outside the on the outer end and the inner ending in a T with hole drilled into it at base of the 4" pvc pipe. On top of that you can place set of drilled pipes as spacers to prevent the airstone from moving up under pressure. Placing your vacuum inlet at the top of the container.
That's be a touch better and safer than the mockup in the article and would provide larger amounts of water/alcohol vapor.
Been shown to work on fuel injected too.
#5
When was the last time you changed your plugs? That would help and make sure you are using premium fuel. People don't realize the components of 87 octane is garbage for our compression engines.
#7
Thanks for the replies so far guys.
#12
I know that NOX is created by extreme combustion tempratures. With what you've done I don't have much to advise.
A friend of mine from Schneider Cams told me something the other day. He runs 9 parts denatured alchohol to 1 part gasoline in the tank, just a gallon or so of it in a nearly empty tank. The car will run like **** since it's not tuned to run properly on alchohol but it supposedly runs extremely clean for the pipe test. I don't know if it would cause a CEL, but he's never had a problem.
By the way I'm not responsible for any damage to your car if you try this. It's something to research and look in to though. If anybody else has heard of this or knows anything about it please speak.
A friend of mine from Schneider Cams told me something the other day. He runs 9 parts denatured alchohol to 1 part gasoline in the tank, just a gallon or so of it in a nearly empty tank. The car will run like **** since it's not tuned to run properly on alchohol but it supposedly runs extremely clean for the pipe test. I don't know if it would cause a CEL, but he's never had a problem.
By the way I'm not responsible for any damage to your car if you try this. It's something to research and look in to though. If anybody else has heard of this or knows anything about it please speak.
Last edited by Flugel89; 09-04-2010 at 02:26 PM.
#14
I'm willing to bet that its your O2 sensors that are at least contributing a good amount to the high NOx. I had the same issues and new ones helped me pass. Should be about $40 each for OEM plug in ones. 2 sensors are the same if i recall before the cat converter. One more sensor downstream from the cat. If you're limited on budget, replacing the 2 upstream ones would be the most beneficial.
#15
Thanks for the new suggestions. Unfortunately I've already changed both upstream AND the downstream o2 sensors, before I even took the first test . I acutally had a check code for the left upstream O2 sensor before the first test, so that was a no brainer (I just went ahead and changed them all)
#16
You can install a water vapor injection system before the throttle body. Tends to lower combustion temps and pollution.
Very cheap to make, here's a basic schematic.
http://journeytoforever.org/biofuel_...earth/me3.html
If you used a 4" pvc pipe with an endcap and topcap, a 4" diameter round airstone from petsmart you could place the airstone directly on top of a 3/4" air stream inlet pipe inserted horizontally through the base of the 4" pipe with a check valve outside the on the outer end and the inner ending in a T with hole drilled into it at base of the 4" pvc pipe. On top of that you can place set of drilled pipes as spacers to prevent the airstone from moving up under pressure. Placing your vacuum inlet at the top of the container.
That's be a touch better and safer than the mockup in the article and would provide larger amounts of water/alcohol vapor.
Been shown to work on fuel injected too.
Very cheap to make, here's a basic schematic.
http://journeytoforever.org/biofuel_...earth/me3.html
If you used a 4" pvc pipe with an endcap and topcap, a 4" diameter round airstone from petsmart you could place the airstone directly on top of a 3/4" air stream inlet pipe inserted horizontally through the base of the 4" pipe with a check valve outside the on the outer end and the inner ending in a T with hole drilled into it at base of the 4" pvc pipe. On top of that you can place set of drilled pipes as spacers to prevent the airstone from moving up under pressure. Placing your vacuum inlet at the top of the container.
That's be a touch better and safer than the mockup in the article and would provide larger amounts of water/alcohol vapor.
Been shown to work on fuel injected too.
#17
Thanks for the new suggestions. Unfortunately I've already changed both upstream AND the downstream o2 sensors, before I even took the first test . I acutally had a check code for the left upstream O2 sensor before the first test, so that was a no brainer (I just went ahead and changed them all)
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