Two days ago I went to my local test only center in Long beach and failed my smog check due to nox. I passed HC (PPM) max 97 meas 3. I passed CO (%) max
0.59 meas 0.00. Failed NO (PPM) max 731 meas 1303. The car is totally stock 93 honda civic cx hb. Two years ago I failed my smog check and bought a new catalytic converter for my car. I also bought a new bosch o2 sensor thinking that was the problem. When I put the Cat in the car, the car passed no problems.

The guy at the test only center thought it was the cat. I do not have a EGR valve on my car so that would not be the problem. The car is properly timed. The car is not running lean I checked the spark plugs. The car does not appear to be running rich either. Can a Cat go out in less than two years? I always thought if the car is properly tuned a cat will last at least 5 years or so.

When I was checking my car today I saw some oil on the spark plug threads of the third cylinder. The oil was not on the electrode but all along the spark plug threads. The oil could not have leaked from the valve cover because I checked that. It was just along the threads. Would that mean I have piston rings that are worn or valve seals? How could I make sure what needs to be replaced? Also the most important thing would this affect nox? Oil leaking into the cylinder? The HC's and CO's were very low wouldn't the oil affect those readings if that was the case? Need some help anyone can give me some insight on this I would appreciate it thanks.

 

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I am not sure if ur car has an egr valve if so check and make sure it is working properly, also excess carbon deposits inside the motor effect NoX, also check ignition timing and before the emisions test retard the timing just a few degrees

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BigLoadChoakHard &raquo;</TD></TR><TR><TD CLASS="quote">I am not sure if ur car has an egr valve if so check and make sure it is working properly, also excess carbon deposits inside the motor effect NoX, also check ignition timing and before the emisions test retard the timing just a few degrees
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Thanks for your input, my car actually does not have a EGR valve. I also did retard the timing a few degrees when I smogged my car. As far as the oil on the spark plug would that affect nox? What would you recommend as far as to get the excess carbon deposits out of the motor? seafoam or gm top engine cleaner?

 

Was the car fully warmed up? I failed bad due to the cat being cold. I suggest you drive the car a good hour before the test and if your waiting rev it at 2000 rpm (yes 2000 rpm) to get the cat nice and hot. Good luck next time around.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Luserkid &raquo;</TD></TR><TR><TD CLASS="quote">Was the car fully warmed up? I failed bad due to the cat being cold. I suggest you drive the car a good hour before the test and if your waiting rev it at 2000 rpm (yes 2000 rpm) to get the cat nice and hot. Good luck next time around. </TD></TR></TABLE>

yes the cat was very hot drove it like hell. Thanks for the input anyone else

 

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