Help please!!! I failed smog...

[M_31_07]

I just failed my smog test, and if there's anyone who can give me some advice I'd really appreciate it. Anyways, here are my readings.

HC
15mph 106(max) 220(meas)
25mph 81(max) 101(meas)

CO
15mph .70(max) .65(meas)
25mph .57(max) .33(meas)

NO
15mph 762(max) 998(meas)
25mph 701(max) 448(meas)

Things that I have done within the past 2 months:
- Denso o2 sensor
- 3" custom piping from the downpipe w/ 3" vibrant catalytic converter to an HKS muffler
- Oil change right before I took the smog test (7/2/09)
- Spark plugs(NGK BCPR6ES)
- Made sure that all fuel injectors were firing

I hope this gives you guys enough information. If I could get some answers maybe I'll fix this myself, if not I'll probably take it to a smog repair station if all else fails. I know that a faulty EGR and other things can lead to high NOX, but does a faulty EGR affect the HC readings also? are these two related? Any advice will be gladly appreciated. Thank you.

 

[Hmong_1G]

Did you let your car sit there in their lot for sometime? Looks like the cat wasn't hot enough? With high NOx and CO.. that usually means a faulty cat or oxygen sensor. High NOx usually leads to advance timing, coolant temp hot, faulty (plugged) EGR. At cruising speed 25mph, your nox is lower ( which means your EGR is working)... just clean its port.


Tips.... clean EGR carbon build up, checked timing, check condition of oxygen sensor ( even if its 2 months old, carbon could've plugged it up)

Before you go to the station drive That 7m hard or take it on a 30-50 minute drive. Go directly to the smog station on time for your appointment. Don't let them wait.

I passed smog ( not dyno smog) with half 91 and half e85 fuel tank, and getting back from a 30mile drive. No cat and a working Emission system. Passed with flying colors (will not work with obd2 and newer or older engines)
lucky me.

 

[M_31_07]

Did you let your car sit there in their lot for sometime? Looks like the cat wasn't hot enough? With high NOx and CO.. that usually means a faulty cat or oxygen sensor. High NOx usually leads to advance timing, coolant temp hot, faulty (plugged) EGR. At cruising speed 25mph, your nox is lower ( which means your EGR is working)... just clean its port.


Tips.... clean EGR carbon build up, checked timing, check condition of oxygen sensor ( even if its 2 months old, carbon could've plugged it up)

Before you go to the station drive That 7m hard or take it on a 30-50 minute drive. Go directly to the smog station on time for your appointment. Don't let them wait.

I passed smog ( not dyno smog) with half 91 and half e85 fuel tank, and getting back from a 30mile drive. No cat and a working Emission system. Passed with flying colors (will not work with obd2 and newer or older engines)
lucky me.

How do I clean the EGR carbon build up? Can I seafoam the car or is that a bad idea? Also the cat is OBD1, should I go with an OBD2? Before I got to the station I drove for maybe a good 20 minutes, and I took the test upon getting there. There wasn't anyone there, so I'm pretty sure the cat was hot enough.

 

[Hmong_1G]

seafoam is a good way of clean up some sludge and carbon build up. Use it through the vacuum only. Don't use it in the oil system as It can reveal leaks ( good if you want to replace the leaks or bad if it becomes major)

Also do a boost leak tester and make sure there isn't any potential vacuum leaks. I still think It's a bad cat as many cats out there are a three stage unit.

http://www.krioma.net/articles/Catalytic Converter/Catalytic Converter.htm ------two minutes of searching. Read and see why a catalytic converter is of the up most importance... and how it functions.

 

[M_31_07]

Alright, let me go and try that. Thanks Hmong 1G.

 

[jdub]

seafoam is a good way of clean up some sludge and carbon build up. Use it through the vacuum only. Don't use it in the oil system as It can reveal leaks ( good if you want to replace the leaks or bad if it becomes major).

Seafoam = snake oil...it is a solvent. Never use this stuff in the oil or fuel system...in fact, never use this stuff period.
.
You can get the exact same result by metering a quart of pure water into the intake manifold...ever seen the cylinder that blew on a BHG? Clean as a whistle. A TB port is preferable for even distribution. A needle valve is the easiest way, but JJ has had success using a basketball needle valve on the pick-up side of the line. You will need a helper to hold RPM at 1500 or so.

NoX is the EGR...yours is likely clogged or the modulator is inop. HC is usually an ignition issue or a lean misfire due to a vac leak.

 

[mecevans]

drive it hard. good gas. fuel system cleaning with pure water. if you dont want to do it yourself ,go to your nearest lube place they should be able to do it for about $10. it also works better if the car is warmed up .

 

[jdub]

drive it hard. good gas. intake/valve cleaning with pure water. if you dont want to do it yourself, go to your nearest lube place they should be able to do it for about $10. it also works better if the car is warmed up .

Fixed that for ya
(water in the fuel system is not good)

 

[mecevans]

Fixed that for ya
(water in the fuel system is not good)

lol. thats what the box is labeled as at work.

 

[M_31_07]

thanks guys, i'll keep this updated when I retest.

 

[M_31_07]

As I said I would here's the update. I didn't want to put this thread to waste especially with the fast responses I got from you guys, thank you. Anyways it took me awhile because the CPS went out so I had to replace that. After fixing that, I bought new NGK Spark plug wires, along with new NGK spark plugs. A friend also told me that my catalytic converter was only a two way, and he had a new Magnaflow hi-flo 3 way and he gave it to me for free and I had a muffler shop weld it on. Made sure there weren't any vacuum leaks, and also that the car wasn't throwing any codes. I took my test earlier today and I finally passed, this was actually my fourth time taking the test.

HC
15mph 106(max) 8(meas)
25mph 81(max) 9(meas)

CO
15mph .70(max) .00(meas)
25mph .57(max) .00(meas)

NO
15mph 762(max) 11(meas)
25mph 701(max) 15(meas)

 

[rayall01]

Congratulations!