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Failed.

XJ Samo

NAXJA Forum User
I just failed smog CO is too high but my HC's are well below the limit.
88 4.0 AW4 231 171,000 miles
Any thoughts?
Thanks, Sam
P.S. I did a search did not find anything about my problem.
 
any chance its a vacuum issue?
 
my 90 XJ came real close the year before to failing. So about two weeks before smogging this year. Ran half can of seafoam though motor and the other half in a full tank of gas. Drove it till almost empty on gas. Then I replaced O2 sensor filled her up ran it real good on the drive to smog station. Passed with flying colors.
 
brandon_750 said:
my 90 XJ came real close the year before to failing. So about two weeks before smogging this year. Ran half can of seafoam though motor and the other half in a full tank of gas. Drove it till almost empty on gas. Then I replaced O2 sensor filled her up ran it real good on the drive to smog station. Passed with flying colors.

yea....musta been the seafoam.

:rolleyes:


My 90 failed.

replaced O2, due anyway after that many years, passed with room.

Rev
 
I had the same problem this past summer. Dealership wouldn't even put my baby on their machine! I ended up leaving it with someone I trust for a week while I was on holidays and he did what he had to do to get it to pass, he did reroute the vacuum lines temporarily, and some other voodoo. Bottom line it passed for only $150.00, no more test for 2 years. Hope this helps, you're not alone.
 
Rev Den said:
Why? got a vac leak?

The recommendation assumes that the vehicle is in decent condition with no vac leaks, or running issues.

Rev

No known vac leak was just wondering everything that runs with vac pressure works fine. My brother suggested it as well as a Jeep mechanic.
Sam
 
No I do not have a vac leak. Just got through checking.
My HC's are low so its not the cat must be O-2 sensor.
I'm now planing to change oil (because Im about 300 miles till its time I change it every 3000 miles) plugs, wires, cap , and rotor, fuel filter and clean and re-oil my K&N. Im taking the jeep in to my buddies shhop to chheck thhe O-2 sensor just because Im curious, planning on changing it anyway but I'm curious. Does anybody have any other ideas before I take it back to re-test for smog?
Thanks Sam
P.S. looked for seafoam could not find and I'm not ordering it on-line.
(Don't want to pay shipping for something that may not work anyway.)
 
Part of my oil change procedure is running a bottle of fuel injector cleaner.
but no I have not tried taking them off and cleaning them.
 
High CO levels are caused by a rich air fuel mixture. possible causes for rich running conditions are fouled spark plugs, leaking injectors, excessive fuel pressure, engine running to cool ( are you running a lower temp t-stat?) or excessive crankcase blowby. A vacuum leak will cause you to go lean, so I wouldnt worry about that. Theoretically speaking if your O2 sensor was biased lean then the motor would try and correct for this condition by adding more fuel and thus creating a rich condition and an increase in CO. O2 would not be a bad place to start, hope that helps
Ryan
 
If anythhing Im running hot Im getting ready to replace my radiator.
I think the o2 is thhe way to go.
Thanks sam
 
A new 02 sensor will be less than 60 bucks. Anyway I have my old one (which still passed) you can try it, just pay me shipping and it's yours. Probably sounds rediculous to be shipping a used o2 sensor but if it works, great. I'm not sure anything was wrong with it or how old it is, I just replaced it anyway. And I kept the old one for some reason.
 
XJ Samo said:
I just failed smog CO is too high but my HC's are well below the limit.
88 4.0 AW4 231 171,000 miles
Any thoughts?
Thanks, Sam
P.S. I did a search did not find anything about my problem.

If his HC's were well in compliance (and he said they were well below the HC limits ) would that not indicate that the Cat might be failing?????? Rather than a bad O2 sensor?????
 
man thats sucks I am not trying to rub it in but I bought a 91 with a blown mototr got a wrecker motor with 260000 on it didnt do anything except change oil and it passed Im a licensed technician at a dealership and well weall couldnt believe it just so you know ran it as it was no voodoo I recommend an 02 sensor and a tune up.good luck
 
XJ Samo said:
I just failed smog CO is too high but my HC's are well below the limit.
88 4.0 AW4 231 171,000 miles
Any thoughts?
Thanks, Sam
P.S. I did a search did not find anything about my problem.

Did they give you a complete report? If so see if there was excess O2 (oxygen) in the exhaust. If there was excess oxygen I would replace the Cat converter. If the O2 was really low than I would replace the O2 sensor.
 
It was the O-2 sensor and a loose intake bolt that created a small vacum leak.
 
Yeah, I was going to ask about that. This is my year to go for inspections (actually, I have until the end of Feb. but I still didn't get anything in the mail)

I bought a locking gas cap last year, made by Stant. Can I just go to testing with that? Some guy suggested I bring the other non-locking cap or else they could fail you?

Stant is a reputable manufacturer so I don't think anything should be leaking with their cap..... It's the unvented locking style FYI.
 
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