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Smog Work

P

Philprof

NAXJA Forum User
Location
Costa Mesa, CA
I failed smog and need some work done (maybe cat and/or ox sensor). Anyone know of good people/shops I can take it too. 2000 XJ. Here's the print out and I have a thread in the OEM section.
SmogFail.jpg
 
Is the check engine light on?

On a 2000 the ecm should be monitoring the cat efficency with pre and post cat O2 sensors

What all did you do to it before taking it to test?
 
No check engine light is on...so, I'm at a loss as I am not an emissions guru:rof:

edit: I did the seafoam treatment too. no improvement (failed second time).
 
Last edited:
Gerr said:
Actually looking at it you failed Nocs I think that's where Grimm failed as well I think he can give ya part numbers for cooler running plugs to help with that
Click to expand...

Cooler plugs will not reduce NOx emissions. A spark plugs heat range is an indicator of the plugs ability do displace heat. If the spark plug runs too hot it will be destroyed. If it runs too cold , deposits will form and it will foul. NOx is a product of combustion chamber heat. Lambda calculations for your printout come to 1.011 which indicates that the vehicle is in fuel control, but it is slightly to the lean side. The O2 sensor is not likely, but it should be tested for response time. If the O2 checks out then a cranking CO2 test needs to be performed on the CAT.
 
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I had a non-Jeep vehicle fail the NOx test. The smog guy told me to put some premium gas in and to get the engine nice and hot before bringing it in for a re-test. I did that the next day and it passed with flying colors.
 
I wasn't very happy with that particular smog shop and the trustworthy repair shop that was next door moved way down Lambert into La Habra because they had too much work for that little location.

Do what the other guys said and maybe look for another shop if you're out of "free" retests. I've used Tune Tech at Lambert and S.F.S. Rd. for years when I couldn't or didn't want to do it myself, but now that I've joined NAXJA I hardly ever need to visit.
 
High NO is usually a result of high combustion temps. With O2 present its possible that:
worst case - you probably have a cracked intake manifold and
medium case - faulty O2 sensor thats not richening up the combustion to burn up all the extra O2.
best case - as mentioned run cooler plugs and make sure the vehicle has been warmed up enough
 
Could be a bad catalytic converter. I don't know much, but I'll tell you what I do know. Air is roughly 79% N2 and 21% O2. N2 is an inert but will react with O2 at high temperatures. This can happen in excess in the combustion chamber if you are running lean (e.g. vacuum leak or something else but any of those would probably give you a check engine light). So If you checked for leaks and adjusted the timing, then it could be the cat.

One job of the cat is break the NOx bond and convert back to N2 and O2 by a section of the converter that uses some catalyst (A catalyst is just something that helps encourage a reaction by lowering the activation energy of a reaction). I don't know what the lifespan of a catalytic converter. I wouldn't think it'd be 10 years but I bet it's possible.

Now I'm not an emissions expert so this is just my opinion.
 
My 89 passes every time, i just run a good tank thru her and the refuel her up and run her up the grade an back down the hill to the smog man...Passes every time..I don't shut it off at the smog mans shop, till he is done
 
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