Okay my 91 240 just failed california smog. It passes everything but NOX... The Maximum Allowable Emmisions at 15mph is 799 and 25mph 738 and the Gross Polluter Limits is 2002 at 15mph and 1802 at 25mph. The car is putting out 4964ppm at 15mph and 4952ppm at 25mph... The guy said it might be a bad EGR or CAT... Anybody have any ideas to help me out? Cause i dont want to spend alot of $ having a shop check it out when it might be something simple i could fix...

Thanks

 

its probably the fact that you have an rb26dett in your car.

 

lol i dont have a rb26 ahhaha... i still have the stock ka24de

 

What I would do is an ecu/engine diagnostic check. If that isn't the problem then I would do a full electrical tune up it might be that simple.
My NOX emission was runnin high because I had bad spark plugs, and even though my ecu wasn't reading the O2 sensor I found out that it was bad also............
I've seen cars pass the cali smog with popped out CATS, I dought it is the CAT, and if the diagnostic doesn't read the the EGR/BPT, then the EGR/BPT isn't the problem........

 

how much do shops normally charge for a diagnostic check? cause i dont have a check engine light... and i was planning on doing seafoam, new plugs, and new oil anyways... but i dont think thats the only problem causing it to be near 5000ppm?

 

praise the lord i live in alabama

 

You can buy an ACTRON code scanner book for about $30, or buy the ACTRON scanner for $150........
When the plugs don't burn fuel, your engine will run rich.......
It has also been tested and proven that an O2 sensor only runs at about 1/2 efficiency after 6000miles, the ecu won't pick up the O2 as a bad sensor ubntil it doesn't work at all, meaning that the signal is cut short......

 

Run your codes.
this should help>
http://www.club240.com/forums/showth...threadid=22144

 

well I heard the airpump doesn't do much but it will be a good idea to check that.

 

Stop Showing off Biotch! Ha Ha J/K

 

Nissans are notoriuos for the bad EGR so it probably is that since it isn't recirculating the spent emissions. I had almost the same issue 2 yrs. ago but I barely got under the allowed #. A cheap trick to pass it would be to change the oil right before you go for the test since that alone carries a lot of pollutants.

 

praise the lord... i live in louisiana lol