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New Owner: Need Help with Emissions!!!!!!!!!!!!!!!!!!!!!!!

Posted: Mon Aug 30, 2010 4:39 pm
by rap633
I bought a 2001 4wd. I live in Colorado and had to pass an emissions test. It passes easily on everything but Nox. The NO level is over twice the limit.
Has anyone here run into this, and do you have any suggestions.

I have already done basic tune up and changed all 4 Cats!!!!!!!!!!!!!!

Re: New Owner: Need Help with Emissions!!!!!!!!!!!!!!!!!!!!!

Posted: Mon Aug 30, 2010 5:36 pm
by fleurys
rap633 wrote:I bought a 2001 4wd. I live in Colorado and had to pass an emissions test. It passes easily on everything but Nox. The NO level is over twice the limit.
Has anyone here run into this, and do you have any suggestions.

I have already done basic tune up and changed all 4 Cats!!!!!!!!!!!!!!
maybe it's because you changed 2 cats too many !@!... There is 2 catalytic converters on your pathy... do you have a check engine light.? maybe your O2 sensors are still running in a rich mode...(open loop)...

What did you change exactly ?? pictures ??

Posted: Mon Aug 30, 2010 8:26 pm
by rap633
I am new to this board, however, I am not new to wrenching. I can't put 4 cats on a vehicle that only takes 2. For part of the manufacturing year labeled 2001 the Pathfinder had a manifold cat as well as a downstream cat on each exhaust. I have listed the part#s from Eastern Catalytic.

LR 6755-05033577
LF 6755-05033579

RR 6755-05033578
RF 6755-05033580

I appreciate you taking the time to post a reply, but in this case I was hoping I might find someone who had the high NO problem. I know the basics that create the issue. Primary culprit appears to be excessively high combution chamber temps. The first thing recomended to check is the EGR valve and vacuum lines to the valve. I have found conflicting info as to whether or not this vehicle has an EGR valve.

Any help anyone could offer would be greatly appreciated.

Thanks,

Richard

Posted: Tue Aug 31, 2010 3:29 am
by fleurys
Thanks.. I just learned something new about my path! :lol:

good luck with your trouble.

Posted: Wed Sep 08, 2010 3:08 pm
by varkrider
I can understand the confusion about the converters. My 2002 has 4 converters installed, but both Bosal and Walker show straight pipes replacing the rear converters.

Bosal Part 760-713, 760-715
http://www.bosalna.com/index.php?mod=catalog