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Unread 05-22-2010, 12:12 PM   #16
twmart
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2001 XJ Cherokee 
 
Join Date: Nov 2007
Location: Denver, CO
Posts: 157
I have a question about the plemun plate / gasket.. After reading some about the Plenum gasket... I checked the following things.
- Looked down the throttle body .. there is only a little oil more like damp.
- I checked the engine vaccum again 16. I removed the PCV and there was no vaccum when I covered the hole with my finger.
- removed the oil fill cap and no vaccum sounds.
also none of the about caused the vaccum to fluctuate it was steady at 16.

Thoughts................................

I am wondering if the PO removed the internals from the cat....

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Unread 05-22-2010, 12:22 PM   #17
BigE3
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Quote:
Originally Posted by twmart View Post
I have a question about the plemun plate / gasket.. After reading some about the Plenum gasket... I checked the following things.
- Looked down the throttle body .. there is only a little oil more like damp.
- I checked the engine vaccum again 16. I removed the PCV and there was no vaccum when I covered the hole with my finger.
- removed the oil fill cap and no vaccum sounds.
also none of the about caused the vaccum to fluctuate it was steady at 16.

Thoughts................................

I am wondering if the PO removed the internals from the cat....
NOx and what the cat is supposed to do is 2 different things
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Unread 05-22-2010, 01:15 PM   #18
twmart
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Quote:
Originally Posted by BigE3 View Post
NOx and what the cat is supposed to do is 2 different things
Maybe I will just do a tune up and oil change the get the free retest and see what the numbers are.. I am only over by .18 on the NOx...
I check one of the plugs Champion RC12YC had a tan color to it.... But the gap was at about .055

I was just thinking also wow OLD oil cause the NOx to read high??? I was thinking that if this Jeep only has 2k miles in the last 2 years then the oil in there is also 2 years oil...
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Last edited by twmart; 05-22-2010 at 03:45 PM..
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Unread 05-23-2010, 12:07 PM   #19
Bossanova
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1993 ZJ 
 
Join Date: Jul 2009
Location: Burnaby B.C.
Posts: 41
Quote:
Originally Posted by BigE3 View Post
NOx and what the cat is supposed to do is 2 different things
catalytic converters: Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 → xCO2 + (x+1)H2O
If your cat is not working your nox will be high. I just failed an aircare here in vancouver and changed the cat and went back through and passed.
you can check your cat to see if its working by using an infrared thermometer. bring the jeep to operating temperature and check the temp of the pipe going into the cat. then point the sensor right on the cat (not on the heat shield) the temp should be allot hotter. this means the cat is working because there is a chemical reaction happening in the cat and when its working it gets damn hot.

Last edited by Bossanova; 05-23-2010 at 12:21 PM..
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Unread 02-06-2013, 06:53 AM   #20
5150Revren
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Join Date: Feb 2013
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Quote:
Originally Posted by Bossanova View Post
catalytic converters: Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 → xCO2 + (x+1)H2O
If your cat is not working your nox will be high. I just failed an aircare here in vancouver and changed the cat and went back through and passed.
you can check your cat to see if its working by using an infrared thermometer. bring the jeep to operating temperature and check the temp of the pipe going into the cat. then point the sensor right on the cat (not on the heat shield) the temp should be allot hotter. this means the cat is working because there is a chemical reaction happening in the cat and when its working it gets damn hot.
This post really helped, thank you!
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Unread 02-06-2013, 09:30 AM   #21
MilanJeep
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Location: Boise, ID
Posts: 293
Put 3-5 gallons of E85 in before your next test, that will help a lot too.
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