smog issue

ok i posted this in oem tech but i figured since cali has the most jacked up laws they might not know so i am reposting here as well

Ok I went to smog my XJ for the first time and HAHA gross polluter. So now i paid for a fail and he told me it needed a cat so i had a cat put on. Now for you smog guru's here are the numbers can you please tell me if it sounds right or will i drive in to give away more money to the smog man with another fail. Keep in mind these numbers are before the new cat, I have not been back after the install. 90 XJ 4.0

15mph co2 14.40 02 0.68 HC max 123 measured 81 CO% max .73 measured .18 NO(ppm) max 711 measured 1905 this was the gross polluter number

25mph co2 14.28 02 .65 HC max 103 measured 73 CO% max .93 measured .33 NO(PPM) max 613 measured 1436 this was a fail

So the NO was the failing number at both speeds which i think is nox this guy also said the 02 reading wasnt right or something
Any help or advice would be appreciated. Thank you in advance
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I found with out gearing and running 33's I kept on failing. So I put a new o2 in and ran smaller tires and passed.

Don't know if this is going to help you?

I have failed smog on my 93 XJ when bought it last Sept and after replaced the cat it passed.

XjPapercut said:

I found with out gearing and running 33's I kept on failing. So I put a new o2 in and ran smaller tires and passed.

Don't know if this is going to help you?

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I was questioning this myself. 33" and 3:55 gears i was wondering if this would kill me

nox is directly related to combustion chamber temps. when is the last time you did a tune up? new plugs, cap, rotor, wires, etc... but your rig is a renix right? (pressure bottle by the firewall) it's pretty easy to pass a renix unless you have a major problem, my MJ passed with a hole in the top of the rotor and 2 terminals on the cap completely rotted out - i can't believe it was even running thats how bad it was.

If it runs good seafoam it (since you have a new cat I would take the downpipe off since seafoaming it will break loose whatever carbon is built up in the intake and on top of the pistons), then put in new plugs and change the cap and rotor, and go back to the smog guy. every place i've seen is pass or dont pay, or pay and free retest. Sounds kind of shady to me if they are making you pay to test it again.

Mine is an HO, but it won't pass unless I put renix plugs in it (colder heat range than my HO - champion #RC9YC) and run a tank of premium through before I go to the smog place. CRC makes a bottle of stuff called "Guaranteed to Pass" as well, dunno what it does but its the only way we can get our delivery trucks at the shop to pass the annual smog check. They should have it at any parts store worth a turd.

HTH

x2 on what Grimm said. I failed with 33's and stock gearing then put on 225/75/15's and failed again so I highly dount gearing is related at all. If you have a Renix, check your EGR is working....the HO's dont have EGR and thats one of the reasons they have a higher failure for NOX because the EGR helps lower temps.

X2 make sure that egr is working

Yeah the gearing wouldnt cause you to fail, if anything help pass I think (less rpm to spin tires at given MPH). Had a 95 wrangler on 33's and stock gearing and it passed. Check egr as others stated, also check vacuum lines. Most places around here only do a free retest if the repairs are done at their shop, luckily I found a local guy thats willing to work with me whenever I have to smog my vehicles...

Actually getting the gearing/ tires close to stock will help nox cause you are taking some load off the engine...might try some stockers on it as well as making sure the egr works.

JXPEEJ said:

Actually getting the gearing/ tires close to stock will help nox cause you are taking some load off the engine...might try some stockers on it as well as making sure the egr works.

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That was my thought too but I have 4 smogs (all fail) that show it didn't make one bit of difference).

GOD i hate CA and there dam smog laws..But we do have some great places to wheel..

silverslk said:

That was my thought too but I have 4 smogs (all fail) that show it didn't make one bit of difference).

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Not saying it works for all but did work for me!

XjPapercut said:

Not saying it works for all but did work for me!

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If you have access to stock sized tires.....I'm sure it's worth swapping out to remove the possibility.

XjPapercut said:

Not saying it works for all but did work for me!

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didn't for me :wave1:

GrimmJeeper said:

didn't for me :wave1:

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hehe

Run all the gas out you have then Put 91 octane in it then try that guarantee to pass stuff that Grimm was talking about (should lower the NOX that's what the bottle says). Drive around on the freeway some then smog test it. Don't forget to do a tune up tho atriot:.

I went back and forth about 91 octane with andy when I had my smog problems, lol. 91 makes my xj run hot.

GrimmJeeper said:

I went back and forth about 91 octane with andy when I had my smog problems, lol. 91 makes my xj run hot.

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This is why i'm no smog guy lol.

Sorry for the bad info.

I got a set of stock wheels and tires you can borrow to do the retest.

XjPapercut said:

This is why i'm no smog guy lol.

Sorry for the bad info.

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not bad info, i'm just saying no 2 jeeps are alike eace:

well i am seafoaming it then running G2P now bottle says run that out before you test is that what you did or do you test with it in there?