Recent content by 95XJmatt

Jeepsrock... cool it passed smog this round by once again disconnecting the cts. Unfortunately not doing any good in the long run and hopefully the smog guy doesnt get a visit from the state for your car lol. Post your failure VIR as well to see how lambda comes out... at this point being that...

Either exhaust leak or your having fuel control issues with the bosch oxygen sensor making it run on the lean side. I would never install a bosch o2 in my nor my customer's jeeps

No actually a lambda reading of 1 is perrrrfect for catalyst operation if your looking at a true automotive calculator that shows you operating ranges. The job of the oxygen sensor is critical in keeping that constant rich/lean toggle thus lighting the catalyst off. Im telling you on these...

Being that your jeep is the year with only a single catalyst not the dual at header theres likely no exhaust leak present... only place to leak is the flange donut gasket or shottie welds around the inlet of the catalyst. Being that you were down there scoping the oxygen sensor Im sure you...

Wow so close not bad dont get discouraged. Your lambda calculations at 15mph .9999 and 25mph 1.001 which is perfect fuel control. Last culprit remains is your magnaflow catalytic converter. Ive had major issues with them on 4.0 ho jeeps they cannot reduce nox enough. The only true way to prove...

Jeepsrock... Coolant flush not going to help... vacuum lines well maybe.. Chemtool waste of time and money not to mention it will poison your oxygen sensor and catalyst Cleaning connections is not going to help... Oil change do it for maintenance... Its so much simpler than this especially...

Also when checking your o2 sensor you want to monitor the pattern with the engine at a consistent speed between 1500 rpm and 2000 rpm. If you have a fluke voltmeter or equivalent setup to record with the engine running at that rpm range for a couple mins and see what the min/max/average voltage...

Yeah but how fast is fast? You need a scope that will tell you the switch rate in milliseconds to be precise and accurate. For HO engines map us as following; .39" vac 4.9volts 3.34" vac 4.6volts 6.3" vac 3.6volts 9.25" vac 3.1volts 12.2" 2.6 volts 15.15" 2.1volts 18.11" 1.6volts 21.06" 1.1...

You will need to backprobe the oxygen sensor connector signal return and ground to monitor the 0-1 volt switch remember must be around 50milliseconds from the low voltage to high voltage. The only proper way to check a map sensor is with a hand held vacuum pump. One is to check for a leaking...

I know and honestly in the years of auto and smog repair ice never seen a jeep with such low emissions i am stoked should be good for years of smogs. The best way and only proper way to check an oxygen sensor is with a digital multimeter and lab scope. Multineter will record high low and average...

Buy from the dealer only for your ntk sensor the mopar part number doesnt match the one cataloged by most part stores... bosch has to be the WORST sensor you can put jn jeeps i only install bosch on euro cars..

Oh also forgot to post lambda calculation on both asm speeds came out to .9997 doesnt get much closer to stoich than that.

Okay here we go boys and girls its time.... no snake oils garbage intake cleaners lucky chicken bones just installing correct parts. Just for kicks since im a smog tech ran jeep in dyno failed nox 300ppm 15mph and 1000ppm 25mph after the walker cat had 100 miles. Put in the new oem ntk oxygen...

Time for me to hijack the post to shed some light for poor jeeprocks. I am a smog tech who unfortunately owns a 95 xj 4.0 ho and currently pulling my hair out trying to fix my nox problem. It has always tested high nox barely passed the last two years. Smog done 12/18 initially failed nox...