Mercedes-Benz Forum banner

Failed Emmissions NOx

1K views 4 replies 3 participants last post by  mountainredneck 
#1 · (Edited)
My vacuum line to the fuel pressure regulator is off and I was just wondering if this is not connected, would this cause me to fail the NOx test. What exactly is the function of this line?

results:
HC 0.3666 Pass Limit = 0.8000 PASSED
CO 8.1048 Pass Limit = 15.0000 PASSED
NOx 3.3999 Pass Limit = 2.0000 FAILED

Thanks
 
#3 ·
you are correct mountain. however, new emissions testing in CA requires a "visual" inspection which will fail you if any hoses appear to be disconnected or in poor condition even if your car is clean at the tailpipe. I failed because my O.E. gas cap (500E) appeared to look old and in poor condition WTF! Wasn't sure what state you were in.
 
#4 ·
I'm in Wisconsin. additionally troubling is my wife took it in and i'm not sure it was completely warmed up. She didn't think she was going to have trouble as I have replaced with new MB parts:
OVP relay
distributer cap and rotor
spark plugs and wires
fuel filter
rear muffler
thermostat
cleaned ICV and replaced both air hoses.
I didn't put on the center resonator muffler, just had a shop install a straight pipe from the cat to the rear muffler (great sound!). I've read that poor cooling can effect the NOx readings; my auxillary fan does not work, it is seized.
Thanks a bunch for helping thus far!
 
#5 ·
man...i can't imagine living under such rules as you guys have. i knew the treehuggers were paranoid, but damn.... failed because the gas cap looked old?? what a line of crap. how did you keep your cool? i live in the great state of georgia. North Georgia. in the hills. yes, we have no emissions laws here in these northern counties. just 3 counties below however, it is just as bad. it is creeping north though. i am sure when that day comes, i will be just as much the rebel that i am now. don,t get me wrong, i am not out pouring oil in the creek, etc. but some of these people doing these inspections are like the staff at your local autozone. they just got out of diapers.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top