Can't pass emissions (Help)

BMW 318i · #1 (**permalink**) 09-05-2009, 04:26 PM

My NOx level is too high for state requirements.
is there a trick to lower the NOx level for the day of the test?? because i dont want to remove my cat and spend aloot of money on a new one.
plz guys any help is greately appreciated.

328istothebone · #2 (**permalink**) 09-17-2009, 07:08 PM

Unless you have a three way cat it doesn't significantly reduce NOx. NOx is formed from too high of combustion chamber temperatures. Make sure you're cooling system is sound and you get a fresh oil change if it's been awhile. That always helps. Also what were your O2 readings? If they were fairly high then you might be running lean.

BMW 318i · #3 (**permalink**) 09-18-2009, 11:42 AM

here is my emission results.

CO2 311.1183
HC 0.7494
CO 5.1007
NOx 3.5331

328istothebone · #4 (**permalink**) 09-18-2009, 04:53 PM

Clean your egr. Egr's sole purpose in life is to reduce NOx

BMW 318i · #5 (**permalink**) 09-19-2009, 02:55 AM

i bought a brand new egr valve and still didnt pass. second time NOx was bit higger with a new egr valve. So i dont know

Matthew C Smith · #6 (**permalink**) 10-03-2009, 06:52 AM

NOx is generated by high combustion temperatures, typically from a slightly lean mixture. How old are your oxygen sensors?

What car is this?

BMW 318i · #7 (**permalink**) 10-03-2009, 11:37 AM

Problem solved... my cat wasnt efficient anough for state requirements. thanks for all the help guys

dinaneurobmw · #8 (**permalink**) 10-16-2009, 10:20 PM

Just future FYI trick to reduce high NOX....drive your car til ur almost out of gas completely and the day before you go to test. go to home depot and buy a gallon of de-natured alcohol and mix with 3 gallons of gas (dosnt matter what octane but mid might be best).pour in ur gas tank and drive at 5 miles to make sure ur now running on ur mixture U will pass the test with flying colors, i didn't believe it... keep driving and use it all up til ur almost out and refill u will be back to normal