1. Home
  2. Pontiac Cars Forum
  3. failed nox on 1990 6000LE

failed nox on 1990 6000LE

new to forum. ya we just bought 90 6000LE w/ 104,300 from florida older couple. clean undercarriage an runs like a charm...no problemos. butbeen told no emission test down south. SO guess what. it just failed its first Mass emissions test. nox is 3.60 all others(HC,OC) ok. so put in new air filter, O2 sensor, pvc, changed oil. have been gettin all kinda opinions on what ta do next before 2nd test. mechanic that did inspection suggested new O2 an thats it?! an if have ta bring to state registered repair shops places want 150+ just ta run diagnostic. dont have local trustworthy mechanic so any suggestions on what to try an replace or/an do next before 2nd test would be appreciated HELP !!!!!

Reply to
legs
Loading thread data ...

NOX is formed under high cylinder pressure and temperature. You need to lower one or both. The EGR valve is designed to lower the temperature. How is it functioing? Or, your mixture could be too lean, however, you replaced the O2 sensor, which should have helped if that were the case. You could have excessive carbon build up, raising cylinder pressure. Try using a "Combustion Chamber" cleaner that removes carbon deposits.

Cheers, Howard

legs wrote:

Reply to
Weird

It'll cost far more replacing parts at random than to have the car properly diagnosed and repaired. GW

Reply to
Geoff Welsh

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.