Also does the cat delete negatively affect the vehicle? This is the current exhaust from the PO.
The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread
- Thread starter Chris
- Start date
Also does the cat delete negatively affect the vehicle? This is the current exhaust from the PO.
9-10 is low. But it also depends on the accuracy of your speedometer. Most folks get 13-14 mpg.
The cat shouldn't affect your mileage. I kept mine on to cut down on fumes and because Oregon is essentially northern California...no rules yet but I'd rather just be ready.
-Mac
The cat shouldn't affect your mileage. I kept mine on to cut down on fumes and because Oregon is essentially northern California...no rules yet but I'd rather just be ready.
-Mac
If you're not throwing any codes I wouldn't worry about the missing CAT. Chances are you need to clean or replace the Idle Air Control Valve. (I'd bet that it, is your culprit.)
https://wranglertjforum.com/threads/how-to-clean-your-iac-idle-air-controller-valve.662/
Edit: I just looked at your profile... if you only have 3" of lift, that is WAY too much transfer case drop!!!
Side note.... question actually... How much lift does your Jeep have?
Because that (red arrow) is a whole lot of transfer case drop!!!
My LJ had a skyjacker lift on it when I bought it. The springs are the only components left. The kit must have included a drop and whoever installed the lift just followed directions and installed the drop. Not required for the LJ, even in a 4-5 inch lift. It was included in the kit if it was being installed in a TJ. I took out the drop and it was just fine. I did not start getting vibrations until I went even higher with an aftermarket skid
Took off the throttle body and cleaned the IAC and housing...no change. decided to unplug the upstream o2. threw the CEL as expected but the issues went away. Just ordered new o2 sensor.
The Lift height is 3.25" It came with that skyjacker transfer case drop. the shocks and springs were real tired so I swapped them with a matching rough country set. the Rough Country kit came with similarly sized drop spacers so I didn't see the need to change it over.
Covering their backsides against drive line vibrations I guess... I hae a 3" Rancho on my first TJ and it only have about a 3/4" drop for the skid.. It just looks like a lot.
Interesting... The upstream is directly lnked to air/fuel ratio, so it could cause a erratic idle, I'm a bit surprised it isn't throwing a code though.. The downstream sensor is just a cat. converter monitor, it does not effect air fuel ratio so I wouldn't messs with that one if there's no code for the condition of the cat...
jim_lukens
New Member
Thanks for this overview. It is very useful and helpful!
Its really challenging to get the right parts as it seems to be a crap shoot as to which type of NTK connector head gets shipped on the parts? I have a 01 4l 6 cyl TJ. The NTK #23138 had the wrong connection head much like the guys in this video
rendering it useless 
even after I went through getting the original sensor out, I had to put it back in, and mail the part back....
How do you figure out the right part with the right connector fittings? I am going to have to take out the part drive to autozone with it and match to the NTK part they order for me before I buy? What an effort? How do the guys do it in the shop?
Any tips on getting siezed ones out other than torch? The bottom 2 are quite in there and I will have to try again with the torch tomorrow
thanks for the help
Its really challenging to get the right parts as it seems to be a crap shoot as to which type of NTK connector head gets shipped on the parts? I have a 01 4l 6 cyl TJ. The NTK #23138 had the wrong connection head much like the guys in this video
even after I went through getting the original sensor out, I had to put it back in, and mail the part back.... How do you figure out the right part with the right connector fittings? I am going to have to take out the part drive to autozone with it and match to the NTK part they order for me before I buy? What an effort? How do the guys do it in the shop?
Any tips on getting siezed ones out other than torch? The bottom 2 are quite in there and I will have to try again with the torch tomorrow
thanks for the help
Thanks for this overview. It is very useful and helpful!
Its really challenging to get the right parts as it seems to be a crap shoot as to which type of NTK connector head gets shipped on the parts? I have a 01 4l 6 cyl TJ. The NTK #23138 had the wrong connection head much like the guys in this videorendering it useless
How do you figure out the right part with the right connector fittings? I am going to have to take out the part drive to autozone with it and match to the NTK part they order for me before I buy? What an effort? How do the guys do it in the shop?
Any tips on getting siezed ones out other than torch? The bottom 2 are quite in there and I will have to try again with the torch tomorrow
thanks for the help
Run your Jeep to full operating temp. Drive around for a bit. And with it still warm, try to break it lose. Should make it a lot easier. Also, try some putting Free-All on it, the day before.
Yes, take your part of and match it. It should save you trips and frustration. Or, disconnect it and take GOOD pictures of the plug from various angles.
jim_lukens
New Member
Ended up using my little propane torch on one of them for like 10 minutes and was able to get one off !
Now I have 2 replaced - one still stuck that I will heat up after the holidays and probably get and one that will be a trip to the store.
The fun of jeeps is that nothing is in a straight line - repairs are almost as fun as 4 wheeling
Thanks everyone for the help and this thread!
Anyone having any luck finding the NTK sensors for the 2000 TJ? I've searched for the last week and can't find any in stock. Is there an "equivalent" replacement since the NTK's seem to be on backorder?
First thing you need to determine is if you have the California eission 2000, or the Federal emissions 2000.
CA has 4 sensors, Fed only has 2. As for suitable replacements for the discontinued NTK brand, there have been some people posting that they have had decent to good results from a couple different brands, a few pages back.
IIRC aome have said Denso and Walker might be good alternatives.
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A step ahead already. I know I have the CA emissions. I just need alternates to the NTK ones. Most auto parts stores around me only have Bosch. I can order Mopar (only 3) but good grief they are expensive.
Quick question. I only get a P0420 when the Jeep has less than 3/4 of a tank AND it idles for more than 5 minutes. Would that still be an O2 sensor?
That code comes back as a bad catalyst, so that points at the downstream sensor on which ever bank it lists, or a cat that is marginal. Idling is the worst thing you can do with a catalytic converter. I'm not quite sure how having less than 3/4 of a tank would factor in to cause that though.
If you let it idle until it comes on, shut it down, clear the code, then start it and idle it again, will it reset the code, or have you even tried that yet. If it does come back after clearing and letting it idle again, I would be more inclined to think it's the cat.
I have done that sequence at the end and the code does not come back. I've also noted, via Torque Pro, that my engine never gets above 187°F. I'm thinking the PO put in a low temp thermostat. I wonder if that could be what is causing the code. I'm going to swap in a 195° thermostat later this week to see if that resolved the problem before I start replacing the cats and O2 sensors.
I can confirm, again that the codes doesn't come back if I do the sequence stated. I also don't have any sluggish performance and my fuel mileage is consistently between 15-18 mpg's (speedo verified by GPS).
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It sounds like your cat might not be getting hot enough to work the way it should, and as it gets older it's efficiency is starting to drop off. Once it gets hot enough it's not throwing the code...
Just a guess but I would focus my attention there first.
I'll swap the thermostat
I did notice on the Torque Pro app that the coolant temp would drop to around 175*F when ideling and around the same time the CEL came on for the P0420.
I'll swap the current thermostat out for a 195*F one later this week when I get it back from the shop getting the lift installed and see what it does with the code. Hopefully that fixes the issue.
I did notice on the Torque Pro app that the coolant temp would drop to around 175*F when ideling and around the same time the CEL came on for the P0420.
I'll swap the current thermostat out for a 195*F one later this week when I get it back from the shop getting the lift installed and see what it does with the code. Hopefully that fixes the issue.