I recently moved to California from Michigan and have to go through all this smogging crap now. I went and got my car smogged today and failed. I failed by having my NO levels too high. Way too high. at 15mph my NO ppm were 5488 where as the max is 799 it says. at 25mph it says 2432 ppm, max of 738. I also failed functional check because the timing is too advanced. The test results page says "Ignition Timing: A10" Im guessing that means its advanced 10deg? I can take care of that no problem. But the NOx levels are throwing me. I dont know of any exhaust leaks or problems with my emissions equipment that would cause the levels to be that high. Even the smog tech said hes never seen it that high, he was kind of a poon though. Any ideas or suggestions? Ive tried reading around and learning what i can about smog and emissions although I can not find a solution to my problem.
My car has no mods or anything that affects performance of the engine, other than the engine being a 95 KA and the timing. I hooked it up properly according to all the information i could find. Although I had to keep the intake manifold and the EGR from the 95 rather than swap it off the 92 KA. Any help would be greatly appreciated.
Smog test results:15mph --- CO2% : 14.10O2% : 1.13HC (ppm) : 38CO% : .03NO (ppm) : 5488
25mph --- CO2% : 14.27O2% : .96HC (ppm) : 57CO% : .01NO (ppm) : 2432
Modified by evlzer0 at 11:44 AM 6/19/2006
1992 240sx w/ 95KA - Smog problems
sounds like you've got an EGR problem. It's a common thing to fail on the 240sx. First thing's first, have a look at the hose that runs from the bpt (saucer shaped thing) to the egr (another saucer shaped thing). Replace that vac hose. Then start up the car, and try pushing up on the egr's saucer shaped section. if it stumbles your egr should be fine and it's move onto the next few things.
Oh yeah before I forget, how long ago did you do a tune up?
Oh yeah before I forget, how long ago did you do a tune up?
Re: (180fan)
Ive checked my EGR by pressing up under the saucer and the car stumbled as if it were going to die. Ill take a look at the hose tomorrow.
As far as a tune up, its probably been since November since ive done a full over (when i completed the swap and started it up). Since then Ive kept up with changing my fluids and filters as reccomended. A total of about 6000 miles since i got it running.
The car Idles quite high @~1100rpm also. I know ive got to reset my timing as well. Im new to all these smog regulations so I have a few questions. I see that I failed for having the timing set too far forward, under the visual inspection / functional check portion. Can I fail for retarding the timing too much as well?
Thanks for the responses, I appreciate the help.
As far as a tune up, its probably been since November since ive done a full over (when i completed the swap and started it up). Since then Ive kept up with changing my fluids and filters as reccomended. A total of about 6000 miles since i got it running.
The car Idles quite high @~1100rpm also. I know ive got to reset my timing as well. Im new to all these smog regulations so I have a few questions. I see that I failed for having the timing set too far forward, under the visual inspection / functional check portion. Can I fail for retarding the timing too much as well?
Thanks for the responses, I appreciate the help.
Advanced timing will drastically increase cyl temps , coupled with the appearant vaccum leak you have [ high idle and high oxygen content on your print out] I am not at all suprised you Nox are so high.
First bring down you timing to spec then observe your idle ,is it still high? If so start trying to track down you leak source. Since your HC's dont really point toward a vaccum leak the high idle and high oxygen content makes it suspicious. However the high oxygen content in the exhuast MAY be due to a small hole in you exhaust system somewhere between the engine and the cat. This too may inrease your Nox since you are flooding the rhodium bed of the cat with the foriegn oxygen entering the stream. The rhodium bed is what seperates the nitrogen molocules from the oxygen molocules, that oxygen is then stored in the second half of the cat for combining to the HC and CO to generate H20 and CO2. You clearly have plenty of O2 by looking at your printout to do the second half and it appears to be working fine.
Your goal here is to cut back the excess O2 which in turn will reduce your Nox. Start with timing as mentioned and go from there.
First bring down you timing to spec then observe your idle ,is it still high? If so start trying to track down you leak source. Since your HC's dont really point toward a vaccum leak the high idle and high oxygen content makes it suspicious. However the high oxygen content in the exhuast MAY be due to a small hole in you exhaust system somewhere between the engine and the cat. This too may inrease your Nox since you are flooding the rhodium bed of the cat with the foriegn oxygen entering the stream. The rhodium bed is what seperates the nitrogen molocules from the oxygen molocules, that oxygen is then stored in the second half of the cat for combining to the HC and CO to generate H20 and CO2. You clearly have plenty of O2 by looking at your printout to do the second half and it appears to be working fine.
Your goal here is to cut back the excess O2 which in turn will reduce your Nox. Start with timing as mentioned and go from there.