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  #1  
Old February 3rd, 2017, 14:11
GoBig06 GoBig06 is offline
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Cali smog test woes...

So I'm required by law in the state of california to get my Cherokee smogged every two years. I went in to get it smogged today and these are the results.... http://imgur.com/a/Jup8o Saddest of sad days. My XJ has been deemed a gross polluter... It looks like my HC and NO are high. What do I need to do to fix this? O2 sensor? New catalytic converter? Also it's a 1999 4.0L with 33x10.5 tires with 4.56 gearing if that matters. My ODB reader comes out clean.

Last edited by GoBig06; February 3rd, 2017 at 14:19.
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  #2  
Old February 3rd, 2017, 14:38
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xCWolf xCWolf is offline
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Re: Cali smog test woes...

lol I like that everything passes so It's running as it's supposed to but they didn't design it for cali in 2017 so sucks to be you.

But as far as helpful input I'm pretty much useless here.

Good luck!
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  #3  
Old February 3rd, 2017, 14:39
96Sportxj 96Sportxj is offline
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Re: Cali smog test woes...

A lot of good info in here.
http://www.naxja.org/forum/showthread.php?t=1077191
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  #4  
Old February 3rd, 2017, 14:41
96Sportxj 96Sportxj is offline
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Re: Cali smog test woes...

You might also buy a 10$ OBDii scanner that connects to your android cellphone and see if any codes are coming up.
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  #5  
Old February 3rd, 2017, 14:44
GoBig06 GoBig06 is offline
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Re: Cali smog test woes...

Quote:
Originally Posted by 96Sportxj View Post
You might also buy a 10$ OBDii scanner that connects to your android cellphone and see if any codes are coming up.
Yeah I got a scanner already. No codes are coming up.
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  #6  
Old February 3rd, 2017, 14:50
GoBig06 GoBig06 is offline
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Re: Cali smog test woes...

So reading up on some of the other threads it looks like HC is from unburned fuel or running too rich. Can running too rich ruin the catalytic converter? Wonder if the burning too rich ruined the cat and lead to super high NO... Should I start investigating on how to fix the HC first?
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  #7  
Old February 3rd, 2017, 15:44
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Tim_MN Tim_MN is offline
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Re: Cali smog test woes...

Yes, running too rich can shorten the life of the cat.

Are all your tune-up parts are fresh, including the coil ?

Get a scanner or an App that shows live PCM data. Determine what specifically beside NO and HC is out of normal ranges.

Probably +60% of Jeep 4.0 exhaust manifolds are cracked. A cracked manifold allows the exhaust to suck clean air, fooling the PCM to think the engine is running lean. The PCM will richen the mixture to compensate for what it "sees".
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  #8  
Old February 3rd, 2017, 16:19
t-bone t-bone is offline
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Re: Cali smog test woes...

BTDT... The OBD2 systems know all; if it's not throwing a code, then your cat is likely just worn out, or is a non-ca spec aftermarket replacement. Are you much over 150k miles? My 1995 ford ranger had very very similar results at 196k, the tech at the smog shop noticed the cat was some non-CA legal aftermarket replacement. I got a CA legal cat put on and the NO and HC levels dropped to less than the "average" value for both. I was shocked at the difference it made.

My 98 xj just passed CA smog yesterday (2/2/17) It has over 250K and the cat has been replaced at least once that I know of. My HC is 23 @15mph, 12 @25mph; NO 146 and 166 respectively.

Hope that helps
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  #9  
Old February 3rd, 2017, 16:48
GoBig06 GoBig06 is offline
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Re: Cali smog test woes...

Quote:
Originally Posted by Tim_MN View Post
Yes, running too rich can shorten the life of the cat.

Are all your tune-up parts are fresh, including the coil ?
Yea I replaced the ignition coil in the summer.

Quote:
Originally Posted by Tim_MN View Post
Get a scanner or an App that shows live PCM data. Determine what specifically beside NO and HC is out of normal ranges.
I have an OBD scanner. Its pretty cheap though. Do more expensive ones have PCM data?

Quote:
Originally Posted by Tim_MN View Post
Probably +60% of Jeep 4.0 exhaust manifolds are cracked. A cracked manifold allows the exhaust to suck clean air, fooling the PCM to think the engine is running lean. The PCM will richen the mixture to compensate for what it "sees".
I'll do some googling to see how to check for cracks in a manifold. Thanks
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  #10  
Old February 3rd, 2017, 16:50
GoBig06 GoBig06 is offline
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Re: Cali smog test woes...

Quote:
Originally Posted by t-bone View Post
BTDT... The OBD2 systems know all; if it's not throwing a code, then your cat is likely just worn out, or is a non-ca spec aftermarket replacement. Are you much over 150k miles? My 1995 ford ranger had very very similar results at 196k, the tech at the smog shop noticed the cat was some non-CA legal aftermarket replacement. I got a CA legal cat put on and the NO and HC levels dropped to less than the "average" value for both. I was shocked at the difference it made.

My 98 xj just passed CA smog yesterday (2/2/17) It has over 250K and the cat has been replaced at least once that I know of. My HC is 23 @15mph, 12 @25mph; NO 146 and 166 respectively.

Hope that helps
I'm at 150k. It looks like the previous owner put a new cat on but I'll check to see if its a cali cat. I might just throw a new one and get a new O2 sensor and try a no pass no pay smog place.
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  #11  
Old February 3rd, 2017, 17:07
GoBig06 GoBig06 is offline
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Re: Cali smog test woes...

Might not be related to the problem but just recently in the past few days its been taking awhile to crank over when the engine is cold but starts up right away when warm. I replaced the battery back in September.
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  #12  
Old February 3rd, 2017, 18:05
96Sportxj 96Sportxj is offline
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Re: Cali smog test woes...

I got the walker non-ca cat from ebay for 100$ shipped. From reading it looks like it is the same as the ca-legal cat they sell but doesn't have the epa stamp.

http://www.naxja.org/forum/showthread.php?t=1136959
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  #13  
Old February 4th, 2017, 07:53
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Tim_MN Tim_MN is offline
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Re: Cali smog test woes...

The cracks are almost always at a weld joint, and usually have reddish dust visible. Using SeaFoam in the intake produces huge clouds of white smoke from the exhaust, some smoke will usually be evident at the cracks.

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Blanket caught in the rear liftgate latch. Now I can't open.
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  #14  
Old February 5th, 2017, 12:13
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Ecomike Ecomike is offline
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Re: Cali smog test woes...

You should use an ohm meter to test the resistance of two hot sensors, the CTS and IAT, both temp sensors. They can affect cold/hot starts. Also you need to test the fuel pressure. If it is low it can cause the engine to run lean and cause high NOx.

You HCs are just barely over the limits. Your NOx is way high, indicating a bad CAT and or lean conditions in the engine. So focus on the NOx problem.

You can test the O2 sensor with an analog Volt meter, live. See my old thread here on O2 sensor testing. But for now I assume the O2 sensor is not the issue, and get a new CAT (see if it must be CAlif-EPA stamped to pass first!!!) first. Then see where you are.

And test the CTS and IAT sensors. The IAT sensor can get dirty and cause some issues, just clean it with soap and water or gasoline..... if it passes the ohm meter test. The FSM and many old threads here list the factory spec for the CTS and IAT resistance (ohms) at various temperatures.
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  #15  
Old March 2nd, 2017, 09:49
96Sportxj 96Sportxj is offline
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Re: Cali smog test woes...

Well did you figure it out?!
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