I failed the "NO" or "NOx"(Nitrous Oxide) part of my smog test. Results were... NO (PPM) Test: 15mph Max: 815 Meas: 1493 (failed) NO (PPM) Test: 25mph Max: 754 Meas: 1024 (failed) Any suggestions on how to move forward from here? Thank you.
Yes, it was warm, temperature gauge in the middle. I've been reading that high NOx can occur for various reasons. Among them, carbon build up on high mileage cars. This brings me to Sea Foam. Perhaps wishful thinking, but could Sea Foam lower the NOx to where it may pass? This depending on carbon buildup, right? I want to also add that the engine for sometime has had a burning or burnt type of odor after turning it off. Like charcoal or something. Thanks.
That could be your charcoal canister then, I would grab a used one and see if that makes the butning smell on shutdown go away
I would seafoam it out, change the plugs if they are old. if it doesn't pass after that replace the converter
Seafoam, Change plugs, drive the bag out of it before your test... I mean redding it. Should be grand then.
Thanks. Ok... I seafoamed it yesterday, that is, the seafoam spray that goes into the intake. The process I used was... - warmed the car, temp gauge in center (normal) - held the rpms steady at 1700 - sprayed 1/2 can in the intake - turn off motor, and waited 20 minutes - turn on motor, let it idle for 5 minutes - drove it aggressively, 0-60s about 6 times, rpms touching the red. A moderate amount of white smoke came out during the process, though I was expecting (hoping) for more, like a thick cloud. It now runs nicely, but it was running nicely before too. As I think of a strategy before going to smog station again, some questions please... Q1. Is there anything in my seafoam process that could be done differently to warrant trying seafoam a second time? For example, using a full can? Q2. Nit-picky question, but I did buy new spark plugs two months ago. I'm open to buying new plugs again, but could cleaning them be just as well? Q3. If I am correct, a new catalytic converter costs in the lower 200s. I did however buy an O2 sensor and plan to have someone install it next week. Could the O2 sensor "do the trick", or in your experience, is the catalytic converter inevitable? I realized that the answers to these questions could be "depending" or be answered either way. Nonetheless, I'm hoping to get an idea on how to move forward and know what to expect. Thanks.
Wow, 3 months and 4 tests later, the car is still not passing smog. Here's the update... Issue: Failed high NOx at 15mph. Max 815, Ave 395, Meas 1283 (Fail). Recent car work done: On the first three smog tests, high NOx failed at both 15mph and 25mph. Within the last 3 months, the following work was done which brought the 25mph NOx down from 1300 to 100 (pass) which was thought to have been attributed to the new cat. Again, 15mph NOx is still currently failing. So you know, I simply want to state that the car seems to run really well. No perceived power is lossed. Now, here's the work that has been done. - O2 sensor - New - EGR valve – New - Catalytic California Converter - New - Spark plugs (platinum) – New - Spark plugs cables – New - Sea Foamed - Fuel Injectors cleaned or new?: 10 months ago. Internet Research: With the above work there must be something that is being overlooked. Perhaps even something simple. The following is some internet information that may or not be applicable (one regarding a 90s camry and the other a 1991 Pick-up SR5). Things are brought up such as the EGR Temperature sensor, EGR Transducer, and VSV Solenoid. Also, vacuum leaks and the fuel filter too. Nonetheless, for review, here they are Regarding the 90s camry http://repairpal.com/failed-emissions-test-due-to-blocked-egr-system-847 Regarding the 1991 Pick-up SR5. This is a lengthy thread but seems to offer good information here and there. http://www.yotatech.com/f116/help-high-nox-15-miles-per-hour-smog-calif-222662/ Thanks.
have you double checked all the vacuum lines? new egr would mean a lot of that stuff would have been unplugged/replugged. hope that helps
The issue has been resolved. It was the EGR Vacuum Modulator which was not allowing vacuum to the EGR Valve. I replaced it an issue was resolved. I am surprised that my mechanic or catalytic converter specialist did not see or test that (almost suspicious). But after the fourth smog test he honestly seemed out of ideas. Not knowing much about EGR things, I did some brief research and discovered the handpump/vacuum air gauge test on those EGR parts. That's how the faulty EGR Vacuum Modulator was discovered. The upside to all of this, is my now good/comfortable understanding about the EGR/Emissions System. The car passed very well. NOx readings were 1/3 that of the average. Thanks all. and as well aeNtraxGT88 for the reminder about the vacuum lines.
