Login  |  Register
Nissanhelp.com - All About Nissan
Do-It-Yourself Maintenance Owners Manuals Recalls/Campaigns Service Bulletins Service Manuals Nissan OBDII Codes Glossary & Acronyms More...
Member's Ride Photos Stock Photo Gallery
Classifieds - For Sale Classifieds - Wanted To Buy Classifieds - Mechanic Wanted Classifieds - Auto Services Search Auto Parts
Register FAQ Social Groups Mark Forums Read
high nitrogen oxide reading in emissions test - 1.7 gpm and limit is 1.5gpm Forums > > high nitrogen oxide reading in emissions test - 1.7 gpm and limit is 1.5gpm high nitrogen oxide reading in emissions test - 1.7 gpm and limit is 1.5gpm
Forgot Password? Join Us!


Pathfinder Nissan Pathfinder Discussion Forum

Reply
 
Thread Tools Display Modes
  #1  
Old 09-25-2022, 02:12 PM
jjdonohue jjdonohue is offline
Registered User
2002 Pathfinder
 
Join Date: Jun 2020
Posts: 2
Question high nitrogen oxide reading in emissions test - 1.7 gpm and limit is 1.5gpm

hello
i did emissions the other day and my 2002 pathfinder passed hc and co, co2 emissions but not nitrogen oxide apparantly, the state of california's standards have infiltrated colorado where i live as of jan 1st 2021. anyway, i passedbefore and now i dont. being an old car, im a little worried that i might not be able to bring it into compliance. However, some background - about 2 years ago i had a P0420 code which is the right bank (passenger side) catalytic efficiency below 95% or someting. so i assumed this would be a cat or o2 sensor issue. i replaced these myself. it worked fine after that, no check enginer light after i did that.
fast forward to now and the emission inspection for Nox fails only. i pulled obd scanner info at my local oreillys and what do you know, no codes and no emissions issues per the scanner. so now the state is telling me i have a failing vehcile but as far as the pathfinder specs are concerned, it is ok. i know a higher nox reading indicates a lean fuel mixture. i dont know exactly where i shuold be at but i took some fuel trim screen shots on the scanner. at 2175 rpm, the scanner says o2 b1s1 is 8.6% and same for stft b1s1. for 02 b1s2 it says 9.4% and stft b1s2 is 9.4% too. when idling at 763 rpm, the numbers are stft b1 = 12.5, ltft b1 =9.4, stft b2 =11.7% and ltft b2 = 9.4%. not sure what this all indicates but if anyone knows that would help. Or if i need other readings, please let me know so i can obtain them.

i started researching this and i came to realize the high nox could be caused by alot of things. i know the driver side cat and 02 sensors are the original but passenger side is only 2 years old as i mentioned. i have about 165k miles on this car. so i know thats one possibility but again no codes. i wonder if it could be a clogged egr, failed pcv valve ( super hard to get to) or a vacuum leak somewhere or maybe an exhaust leak someplace that i dont know about. again, no codes from the computer. thoughts on this? i would like to try and avoid a costly repair because the state has limits that are unreasonable for an old car. i also thought about running cleaners through the car like heet to see if i could "fake it" and pass.
Reply With Quote
Reply

Tags
emissions, high, nitrogen, oxide, reading

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 02:55 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Search Engine Optimisation provided by DragonByte SEO v2.0.42 (Pro) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.