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High CO in CA - smog help!!

ParadiseXJ

NAXJA Forum User
My old XJ, 90, 4.0, AW4...now my son's XJ...has been mostly sitting for the last year. Short trips, 'round town a bit, being started and run up to temp every week or so.

He had to register it, and get it smogged. Failed smog on CO.

Allowed measurment (passing) is 1.0
Measured amount 2.16 (failed) at idle.
Measured amount 2.90 at 2500 rpm (failed) "Gross Polluter" staus

So, now he has to take it to a Gross Polluter station to get it smogged and finally register it. It passed all the other tests with great numbers, vacuum, EGR, NoX, etc. all good.

My question: Would the Jeep virtually sitting for a year have an effect on the CO levels if he just started it, and then drove only about 2 miles to smog it without the thing ever getting really up to temp?

It starts, runs and drives like a champ, no sign of trouble, decent mileage. Would getting it out on the highway and "blowing it out" for a hundred or so miles solve my problem...or does high CO indicate a specific problem??
 
CO is usually a sign of unburned fuel in the pipe. Sounds like it's running rich.
How old is the fuel in the tank? You ALWAYS want to run it hard and get it good and hot before emissions test. Maybe run some MMO or seafoam in the tank, top it off and drive the crap out of it for at least 1/4 tank.
 
Make sure your o2 sensor is good and the CTS and MAT are working well.

Any of these not working will put it in Open Loop and it will run well as it is running rich.
 
Agree with ALL of the above, but especially OLD FUEL that may not be "seasonally" correct.
 
Well, I'm trying to troubleshoot this over the wire. I told him to drive it, push it a bit, at least 30 minutes and drive it in to the smog station. Failing that, he can drive it here and learn some TSing with the DMM before buying parts.

Your (anyone's) intuition?? O2 bad? ...or wait and see?
 
Well, I'm trying to troubleshoot this over the wire. I told him to drive it, push it a bit, at least 30 minutes and drive it in to the smog station. Failing that, he can drive it here and learn some TSing with the DMM before buying parts.

Your (anyone's) intuition?? O2 bad? ...or wait and see?

Could be that simple. If your son can swap it, why not? Otherwise, I say try again.
 
Is it a Renix? I assume it is, since you mentioned the EGR, Year?

Bad cat and problems with the O2 sensor system (wires, or sensor) are at the top of the list.
 
When was the oil changed last?

If its old and the jeep was mostly used for short trips there are going to bee to much unburnt fuel in the oil and that can really screw with the numbers.

In my -89 i always have to do an oilchange a couple of days before i go and get it inspected. That + fresh gas and drive like you stole it to the station and it will usually be fine.
And dont turn off the engine while waiting let it sit idling to keep the cat at its working temp
 
o2 sensor. plugs, plug wires, cap and rotor, oil change, and throw some acetone in the gas tank before you smog it, maybe a pint or so, i do more than that. inspect the cat as well.
 
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