Emissions
04-16-2016, 10:48 PM
#1
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Model: Cherokee
Emissions
So I can not pass emissions. First test was 2980 on HC high speed test the machine won't let me press on to the idle test so things I have changed
Map sensor
O2 sensor
New cat
Head re built from machine shop
New header (oem one was cracked)
Cap,rotor,wires,plugs
Ecu reset multiple times
New Coolant sensor for ecu
New coolant sensor for gauge just in case I'm not seeing it wasn't getting out whatever loop I forget
I've done a 2 hour hwy drive to get the cat hot
Plugs are gapped to .035
Fuel pump/sending unit
4 hole injectors
Vacuum lines have been checked 12 times for leaks and correct routing
After the new head it went down to 522 on hc again machine won't let me press on to idle test. Now it's pulling a 52 code saying left bank is lean/rich. I'm lost on what it can be and given up. If you see in the introduction section I really hate this jeep. Any help would be great any input would be great.
Map sensor
O2 sensor
New cat
Head re built from machine shop
New header (oem one was cracked)
Cap,rotor,wires,plugs
Ecu reset multiple times
New Coolant sensor for ecu
New coolant sensor for gauge just in case I'm not seeing it wasn't getting out whatever loop I forget
I've done a 2 hour hwy drive to get the cat hot
Plugs are gapped to .035
Fuel pump/sending unit
4 hole injectors
Vacuum lines have been checked 12 times for leaks and correct routing
After the new head it went down to 522 on hc again machine won't let me press on to idle test. Now it's pulling a 52 code saying left bank is lean/rich. I'm lost on what it can be and given up. If you see in the introduction section I really hate this jeep. Any help would be great any input would be great.
04-17-2016, 01:10 AM
#2
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
That's a tough one.
I just got mine tested and at 15 MPH HC result was 86... max is 86. So I'm good until 2018. I need a few things before that time comes, but not sure I'd chase this smog thing like you have.
My motor has never been apart and it has 181,000.
Over 25 years I replaced...
- O2 sensor
- CAT
- distributor
- radiator
I need a new header because it has a crack..
I don't know how to help... perhaps go over to NAXJA - there's a big thread on smog in OEM section.
.
I just got mine tested and at 15 MPH HC result was 86... max is 86. So I'm good until 2018. I need a few things before that time comes, but not sure I'd chase this smog thing like you have.
My motor has never been apart and it has 181,000.
Over 25 years I replaced...
- O2 sensor
- CAT
- distributor
- radiator
I need a new header because it has a crack..
I don't know how to help... perhaps go over to NAXJA - there's a big thread on smog in OEM section.
.
04-17-2016, 01:26 AM
#3
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
Perhaps this can help hone in on the problem...
http://m.smogtips.com/failed-high-hydrocarbons-HC.cfm
I know I'll be installing a new header and CAT before my next test.
.
http://m.smogtips.com/failed-high-hydrocarbons-HC.cfm
I know I'll be installing a new header and CAT before my next test.
.
04-17-2016, 02:20 AM
#4
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Thanks for the Input I've built plenty of motors and trouble shooting I would say I'm decent but this has me questioning everything I know about emissions bs. I finally broke down and took it to a shop I'll post up what they find and share because I don't want anyone to go through the stress and money that I've done so far.
04-17-2016, 02:23 AM
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Perhaps this can help hone in on the problem...
http://m.smogtips.com/failed-high-hydrocarbons-HC.cfm
I know I'll be installing a new header and CAT before my next test.
.
http://m.smogtips.com/failed-high-hydrocarbons-HC.cfm
I know I'll be installing a new header and CAT before my next test.
.
04-17-2016, 02:39 AM
#6
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
Also... I've read huge tires makes it tougher to pass..
.
Last edited by M998; 04-17-2016 at 02:47 AM.
04-17-2016, 02:46 AM
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
Read.. I've been a member there a real long time.
http://www.naxja.org/forum/showthread.php?t=1077191
.
http://www.naxja.org/forum/showthread.php?t=1077191
.
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04-17-2016, 11:49 AM
#8
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165000 and I would agree with that of it were on dyno type test but all they do is rev it between 2300 and 2700.
04-17-2016, 11:55 AM
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Year: 1991
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Engine: 4.0L HO
04-18-2016, 02:14 AM
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Model: Cherokee
From Allpar:
What year do you have? What brand O2 did you use?
Code 52 is triggered when the engine has been running rich for more than 11 minutes, 55 seconds.
If the condition which causes code 51 or 52 continues for four times the time it took to set the code (roughly 48 minutes), the engine will run in closed loop mode, which forces it to run rich, preventing it from running lean (running lean can cause severe damage)
*poor wiring or connection to O2 sensor
*Defective O2 Sensor
*Engine rich for another reason
If the condition which causes code 51 or 52 continues for four times the time it took to set the code (roughly 48 minutes), the engine will run in closed loop mode, which forces it to run rich, preventing it from running lean (running lean can cause severe damage)
*poor wiring or connection to O2 sensor
*Defective O2 Sensor
*Engine rich for another reason
What year do you have? What brand O2 did you use?
Last edited by Radi; 04-18-2016 at 02:21 AM.
04-18-2016, 10:44 AM
#13
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Year: 1991
Model: Cherokee
Engine: 4.0L HO
I was curious about that too... I always buy OEM sensors.
Here's an excerpt from a member on NAXJA... The Smog Thread.
I know the NAXJA thread is about NOx and not HC. I've never bought aftermarket sensors. This is the reason...
Here's an excerpt from a member on NAXJA... The Smog Thread.
I know the NAXJA thread is about NOx and not HC. I've never bought aftermarket sensors. This is the reason...
Time to shed light:
Being cheap hurts!
Replacing my denso oxygen sensor with a OEM NTK brand sensor which is designed to switch at a faster rate than most others will. Jeeps are very dependent on a fast o2 sensor - as there is nothing to help nox! If a sensor on jeeps is switching from rich to lean over 50 milliseconds - its junk... mine is right on the treshold of junk... new sensor and retest with 91 octane tomorrow. I've fixed customers cars nox failures in the past using a better o2 sensor its all about the switch rate... lazy sensors create lots of nox problems.
------------------------------------------------------------------------------------
Just for kicks since im a smog tech, ran jeep on dyno and failed nox 300ppm 15mph and 1000ppm 25mph after the walker cat had 100 miles. Put in the new oem ntk oxygen sensor drove the jeep for 20 miles modestly not superheating the cat as many suggest then re smogged to find nox now 4ppm 15mph and 84ppm 25mph.
1995 xj 4.0
200000 miles original engine
Being cheap hurts!
Replacing my denso oxygen sensor with a OEM NTK brand sensor which is designed to switch at a faster rate than most others will. Jeeps are very dependent on a fast o2 sensor - as there is nothing to help nox! If a sensor on jeeps is switching from rich to lean over 50 milliseconds - its junk... mine is right on the treshold of junk... new sensor and retest with 91 octane tomorrow. I've fixed customers cars nox failures in the past using a better o2 sensor its all about the switch rate... lazy sensors create lots of nox problems.
------------------------------------------------------------------------------------
Just for kicks since im a smog tech, ran jeep on dyno and failed nox 300ppm 15mph and 1000ppm 25mph after the walker cat had 100 miles. Put in the new oem ntk oxygen sensor drove the jeep for 20 miles modestly not superheating the cat as many suggest then re smogged to find nox now 4ppm 15mph and 84ppm 25mph.
1995 xj 4.0
200000 miles original engine
04-19-2016, 02:17 AM
#14
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Ok update jeep finally passed emissions turns out the O2 sensor I got from autozone was junk of the fact I was actually running 10000ppm hc for 30 some days may have screwed it up. Also there was interference between my injectors and the o2 sensor wire harness. I'm glad this is all behind me so for anyone who is having trouble shoot me a message I would consider myself an expert in jeeps with emissions issues. I'll note for whoever reads this in the future all test were done with 85 octane and I never added a fuel injector cleaner to the tank. I only did the diy seafoam fogger you can buy at the auto parts store.
04-19-2016, 08:53 AM
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Ok update jeep finally passed emissions turns out the O2 sensor I got from autozone was junk of the fact I was actually running 10000ppm hc for 30 some days may have screwed it up. Also there was interference between my injectors and the o2 sensor wire harness. I'm glad this is all behind me so for anyone who is having trouble shoot me a message I would consider myself an expert in jeeps with emissions issues. I'll note for whoever reads this in the future all test were done with 85 octane and I never added a fuel injector cleaner to the tank. I only did the diy seafoam fogger you can buy at the auto parts store.
I can tell you a little story about XJ injectors. I still have the stock OEM injectors. But you'll want to run Chevron gas with Techron to keep them clean. It's a long story, so I can't go into it now..
The other thing, I always run 91 octane and a few weeks before going in for a smog test I run a tank with Techron concentrate.. but you need to run that tank out before going in for your test.
Also... Now that we're talking about fuel, be sure to check your high pressure fuel line periodically.. It can develop a pinhole leak in the plastic near the front where it curves and will spray fuel on the header. It's not visible unless you're looking for it and move the line around.
They changed the design because the replacement line is more robust.. should have been a recall on that one.
Probably why some XJ's have burned to the ground...
Have fun..
.
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