ThePOWERtoRULE

Ok, I smogged it today.
Jeep has new plugs, wires, car, and rotor. Runs great. Starts a tiny bit hard, but I that's just how it is. It never takes more than about 15 seconds of cranking.

Results:
15MPH TEST
1644 RPM
HC:
Max- 123
Measured- 134 FAIL
CO%:
Max- .73
Measued- .77 FAIL
NOx:
Max- 1015
Measured- 2885 FAIL: GROSS POLLUTER

25MPH TEST
1602 RPM
HC:
Max- 103
Measured- 121 FAIL
CO%:
Max- .93
Measured- .79 PASS
NOx:
Max- 875
Measuered- 2476 FAIL: GROSS POLLUTER

I know a bit, but I've never had a vehicle fail at every single aspect of the smog check. Where should I begin?

Please, spare me the "Move to another state" responses.

89Laredo

We dont have emissions checks in Michigan.
But theres been enough of these threads that I can tell these things Ive heard help.
A new gas cap.
Renix cherokees do not have a CEL, if your o2 sensor is bad, there is nothing to tell you. I would change your oxygen sensor if it hasnt been replaced in a while.
Go to the test with a full tank of gas.
Make sure the jeep is fully warmed to operating temp when tested.
Check for vaccum and exhaust leaks.
Clean your throttle body.
Do a tune up and change your oil before the test.

Hopefully some other people that have had to pass emissions can suggest some other things..

Abovetimberline

It looks like incomplete combustion but not that bad,with all you have changed did you do a compression check?how old is your cat? The big issue is the nox,in northern ca we do not check nox,nox is a product of high o2 and heat,which says the 02 is not being used up in the combustion process,i would start with compression check.

Throttle Jockey

used to live in FLA, they tried the emissions inspection about ten years ago. too many cars were failing to continue testing. they were condeming better than half of the cars that they tested. something to try. run 93 octane when you go for the test. higher octane is a slower more complete burn. and as stated before, make sure its good and warmed up. if you have to hold it off idle a bit while your waiting your turn.

Willys55

nox that high ...replace the cat, also replace the o2 sensor and that should trim out your co

Willys55

is this high mileage engine? HC are the result of excess oil in the mix, valve guide seals and oil rings will lead to this. Some times (if they don't look under the hood) you can pull the pcv out and plug the hose to pre vent a vacuum leak. and it would lower your HC a bit and possibly get ya under the limit

ThePOWERtoRULE

I didn't do a compression check, the % of O2 measured was .6 at both speeds. Catalytic converter is about 8 years old.

I ran around town for about 30 minutes before the smog check and then idled about 10 before it was my turn.

I got an oxygen sensor today and I'll be replacing it tomorrow. I'm trying to avoid replacing the Cat.

Engine has about 70k mi on a rebuild, 191k mi total. Would I plug the hose coming from the back of the VC to the intake mani for this or the hose coming from the front of the VC to the airbox?




Also notable, I Seafoamed it (through the intake) last night and afterwards ran it for about 30 minutes last night, about 5 minutes at reasonably high (3rd gear at 55mph) RPM to blast out any deposits. Unfortunately I didn't notice until I was at the smog check, but there were still some traces of the Seafoam fog (akin to London Fog in my experiences) coming out of the tail pipe at speed. Could this have adversely affected my outcome?

Also, after the Seafoam treatment I have a bit of milky substance on the very very tip of my dipstick. The oil has been clean after the two 40 mile drives I've taken the Jeep on since I got it... and now all of the sudden I see that? Is my HG going????

Abovetimberline

Any smog tech worth his licence will notice any tampering to your emissions,(pvc)I would not suggest doing that,if they fail you for tampering you will end up at the refs place to get it cleared for smog. Take it in the way is was designed. I would run it around for a couple of days before trying it again. Did they do a pretest or did your jeep get reported as a gross polluter?
The other thing is once you fail you can get the tops for the rear window for 60 days for $50 to give you more time to correct any issues.

c-loss

X2. I failed mine last year and thats what it was. The o2 sensor is easy enough to get to and I just took the jeep in and a whole new exhaust put under it. But that should help you out.

ThePOWERtoRULE

No, it was a straight test, but it wouldn't have made a difference anyways. It was designated a gross polluter two years ago. That's why the PO parked it in the yard and let it sit for about 2 years.

That's also the reason I can't get a temp tag for it, because it hasn't been validly registered or insured in about two years. I guess this is how $300 Jeeps begin their second life.

Abovetimberline

It is tough here,and alot tougher where you are at.the dyno style test is not done up here,they use it in heavy populated areas.
I would still do a compression test and make sure it is ok mechanicaly,120-150lbs. The rest is and easy fix,or alot easier than having low compression. With those miles it is more than likley ok but still a good idea to make sure.

4.3L XJ

OK, don't move. I live in CA also. Anyway, the first thing you should do is change your O2 sensor, that will take care of your HC and CO. You should change it periodically anyway. This is the most neglected tune up part on any vehicle. They are more than $1.98, but you gotta do it. I usually use Bosch.

Not sure about the NO, but that is controlled by the EGR. It might be plugged up. Won't cost you anything to check it.

Abovetimberline

That is a good point,what you can do is apply vacuum to the egr from any vacuum source while your engine is running and see if it stumbles,(I just remove a line and use that,the shop uses a hand held vacuum pump).,it should almost kill the engine,if it does not then the egr is stuck closed,that is one of the tests that is performed during inspection,if it opens then check all your vacuum lines to the egr solenoid on the firewall and to the egr to make sure they are right,you can use the emissions sticker under the hood for refrence

X-J

My 88 failed because of a bad egr , so i re-routed some vacuum lines to get it to stay open and it passed with good numbers -
But in between idle and go it would hesitate if you didn't give it enough gas. when routed the wrong way - i think the round black vacuum check valve thing next to the egr is bad and not the egr in my case, and you cant buy just that part, you have to buy it as a part of the egr package

Abovetimberline

If your egr is open at idle it will act like a huge vacuum leak,I am not familiar with texas procedures but here in northern ca they only check it at idle to make sure it stumbles,and in southern ca they check nox,we do not. The little black saucer is the backpressure transducer.