Originally Posted by TomCat39

There is a few things to do, first off, did you get the car fully warm before going to emissions? Drive on the highway for 20 minutes then go to your smog place. When in line hold the rpm to 2K until you get in, that keeps the Catalytic Converter hot. It will not do it's job when cold.

Have you done a compression test to see if your rings are in decent shape, if the compression is at the bottom end of spec, it will be harder to pass.

Not sure if they have it in the states but you can also try, Guaranteed to Pass additive. It's rather hard on the car so they say only do it once a year at most.

You did a tune up so that will help too.

If you have two O2 sensors I would think you would have an EGR valve but you didn't post year make of car or what motor you have so no way to verify.

The typical spots for high NOX is EGR problems, you say you don't have an EGR system. Advanced Ignition Timing, you did a tune up so should have set the ignition timing, a little retard might help reduce NOX, so that should be ruled out, then there is the three way catalytic converter, if it's bad you will get high NOX. And lastly, combustion chamber deposits but you seafoamed the car twice so that should help with the combustion chamber. I personally enjoy the Italian Tune Up method to burn out deposits but finding safe places to do that is not so easy.

Really, other than a bad cat, I think you've covered most of the areas that cause bad NOX reading for the car so should be in decent shape for your next test.

Originally Posted by tayone415

but the car sat for about 30 mins

Originally Posted by TomCat39

There is a few things to do, first off, did you get the car fully warm before going to emissions? Drive on the highway for 20 minutes then go to your smog place. When in line hold the rpm to 2K until you get in, that keeps the Catalytic Converter hot. It will not do it's job when cold.

Have you done a compression test to see if your rings are in decent shape, if the compression is at the bottom end of spec, it will be harder to pass.

Not sure if they have it in the states but you can also try, Guaranteed to Pass additive. It's rather hard on the car so they say only do it once a year at most.

You did a tune up so that will help too.

If you have two O2 sensors I would think you would have an EGR valve but you didn't post year make of car or what motor you have so no way to verify.

I put guarantee 2 pass last night. Now after plugs wires cap and rotor car is fuel efficient and can't burn the tank down fast enough to do smog for awhile.
The typical spots for high NOX is EGR problems, you say you don't have an EGR system. Advanced Ignition Timing, you did a tune up so should have set the ignition timing, a little retard might help reduce NOX, so that should be ruled out, then there is the three way catalytic converter, if it's bad you will get high NOX. And lastly, combustion chamber deposits but you seafoamed the car twice so that should help with the combustion chamber. I personally enjoy the Italian Tune Up method to burn out deposits but finding safe places to do that is not so easy.

Really, other than a bad cat, I think you've covered most of the areas that cause bad NOX reading for the car so should be in decent shape for your next test.

Originally Posted by TomCat39

took 5 minutes to find your reply. you stuck in the quote of my reply.

follow the directions of guaranteed to pass to the letter. don't go to smog with it in the fuel.

Also, you said you added a fuel injection cleaner, did you get through that tank of gas first before you added the guaranteed to pass? probably not the best thing to have both additives in one tank of gas. If not too late now, so burn that full tank of gas, refill up, drive at least an 1/8th of the tank then go for smog. if you aren't legal to drive ie no permit or plate then you can idle the car all day until the tank is near empty. will take awhile but can be done without driving.

Originally Posted by TomCat39

took 5 minutes to find your reply. you stuck in the quote of my reply.

follow the directions of guaranteed to pass to the letter. don't go to smog with it in the fuel.

Also, you said you added a fuel injection cleaner, did you get through that tank of gas first before you added the guaranteed to pass? probably not the best thing to have both additives in one tank of gas. If not too late now, so burn that full tank of gas, refill up, drive at least an 1/8th of the tank then go for smog. if you aren't legal to drive ie no permit or plate then you can idle the car all day until the tank is near empty. will take awhile but can be done without driving.

Originally Posted by tayone415

No guarantee to pass is the 1st and only fuel additive in the tank. After getting the oil change, 1st o2 sensor and pcv valve and plugs wires cap and rotor the car is getting way better gas mileage Im having a hard time running the gas out when before a little less than a 1/2 a tank was on 70 miles now I got 110 with about 1/8 th a tank and trying to burn gas. Hopefully it means it's all fixed now?

Originally Posted by TomCat39

Yeah, jsut like Ron stated, do a full tune up and you should have no issues with smog. The can of Guaranteed to pass was probably a waste of money and uneccessary strain on your motor. It's one of those last resort sort of things. Was suggesting it for a case of you failing a second time after doing a full tune up.

But it's in now so might as well follow through, can't do smog with the additive still in the tank. Have to finish that tank of gas then refill, then do smog.

Originally Posted by RonJ@HT

Good luck

Originally Posted by slowcivic2k

You have in increase in all poor-combustion related elements. Your O2 was higher, CO, and NOX, NOX is the odd-duck here. Since your combustion efficiency at the "tailpipe" is higher at 25mph, The only thing that can produce NOx at those levels with a decrease in combustion at 15mph is a failed converter. Has the converter ever been replaced before?

I would compression test it just for the sake of diagnostics.

Originally Posted by tayone415

Not sure if the cat was ever replaced? But, I didn't drive the car enough before trying to smog it, all the parts were carb legal and I sea foamed it 2 days before, and it drove fine with no hesitation or stalling and the rpms are normal, but later found the mpg to be horrible. Now the mpg is way up. They told me the car wasn't burning fuel, and I found the plugs, wires and cap, and rotor were bad, the pcv valve was done and the the primary o2 wasn't even hot after a 40-50 min drive, but replaced all of it. But, I didn't see the smog tech use a sniffer, just seen him plug in the scan tool.

Do you think it's still the cat failing?

Originally Posted by purgat0ry

What did you do after the seafoam?
how did you seafoam it?
Details

Originally Posted by TomCat39

You should pass without issue. The biggest help is to keep the cat hot while you wait in line. Turning the car off for 30 minutes before the test lets the cat get cold and then it won't do it's job properly or fully or as efficiently.

Originally Posted by TomCat39

You should pass without issue. The biggest help is to keep the cat hot while you wait in line. Turning the car off for 30 minutes before the test lets the cat get cold and then it won't do it's job properly or fully or as efficiently.

Originally Posted by dude_123

NOx will not go down if there is a very small air leak right before the cat. NOx will not be reduce when you have a lot of oxygen present. Fix your leak in the exhaust system before the cat and it will drastically lower your NOx emissions.