Hint, hint. It's probably the oxygen sensor. test it.

 

I just got a better look at the test results, (and discovered "zoom"-"Ctrl +" )

"passed equipment inspection"---so he didn't see the busted tube. Academic question: So a bad O2 sensor can raise NOx. I wonder how that works?

By the way, my 90 needed an O2 sensor to pass, but the HC had been high.

"I was thinking since the system wasn't recirculating the exhaust that it was causing the high NOx. " ----NOx IS what the egr is about. Also I think the computer is 1/2 blind without a good 02 sensor.

 

your in Maricopa county.... go down to Pima county and register it there. NO EMMISIONS. just get a PO box in Pima and use that for your regiastration address. then no need to go to the sniffers. hack off the emissions, through on headers, convert your rig to run on endanger animals.

(i lived in AZ for 10+yrs)

 

I know the easy way out would be to go to a county north or south of me that does not require emissions testing and open up a p.o. box, but my wife made it very clear that that is not an option for me. I have to do it the "right" way or sell it. I don't want to sell it, that wouldn't be fair to Pablo (that's what my wife named it). Besides I'm learning so much about these stupid emissions.

Agent_Oragnge this had me rolling at work!!

 

Here you go http://www.lunghd.com/Tech_Articles/...iagnostics.htm enjoy. A guy on this forum Eepower54 I believe is his handle, lives near me. He has an 88. They told him at smog he needed a cat. His numbers were super high. I tested his sensors and he had a bad o2. We replaced that and did a full tune up, we seafoamed the engine (vacuum line, oil, and in the gas tank) he drove like 50 miles and changed the oil and what do ya know.... passed with very low numbers. When you test the o2 I find the easiest way is to warm it up and back probe the wires. With one probe in ground one of the other (think its the middle) wires will jump in voltage every second or so. Test them sensors, get a new egr tube at a junkyards, tune it up and seafoam it.... bet it passes.

 

Ok, so I found a local wrecking yard devoted to all things Jeep http://www.amc4x4.com/ I bought the ERG tube for $10 and installed it this afternoon. I could hear the ecu functioning after I first turned on the engine, or at least some noise at first but it stopped after I put it in drive. I'm not sure if it will effect the emissions numbers yet, I still need to check the O2 sensor and I'm going to run seafoam through before I take it in to test.

 

ECUs are stone quiet.............They're mounted up under the dash inside the Jeep.
Now the random voices I hear in my head, I have no clue where they originate.

 

Typo, I ment to say I heard a noise near the ERG. I assume it was the EGR allowing back it or sealing up it stooped after a second.

 

Ya. If it didn't stop you got a problem. Test the sensors and egr and solenoid. You'll find your problem.

 

EGR valve's sole purpose in life is to reduce combustion temperature, reducing NOx emissions.
Bad O2 sensor usually results in engine running rich, resulting in high CO and HC.
I would bet that getting EGR valve to function properly will get you past e-test.

 

So the noise I heard is the EGR valve, I can see the valve move slightly when I hear the noise. It sounds like a buzzing sound, as if the valve is touching something that is spinning fast.
Also I unplugged the mat sensor on the manifold and plugged it back in and now the motor will rev past 2000rpms with out bogging down!
I still haven't checked the O2 sensor, that's on the plate for tomorrow. At least I can drive on the freeway with out people passing me and honking cause I'm driving so slow

 

Well I hooked up the EGR valve the right way last night and I noticed my exhaust manifold was cracking on the welds, is this common in older Cherokees?

 

Yup... causes o2 issues.

 

Well I picked up this oem manifold last night

So tomorrow after work I'll start taking the manifolds off and put the new one in.

 

I too live in the PHX area and have just passed my emission licensing test (4th year now) and agree with the EGR malfunction to be the cause of your high NOx this is when oxygen and nitrogen bind at about 2200+ degrees in the combustion chamber. keep us informed on how your retest goes.