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Jerry Bransford

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I don't have a clue when they were last changed, I know jerry swears by autolite but getting the correct ones in the UK is sometimes quite difficult and quite costly. So ive got a full set of NGK ZFR5N ordered to get installed.A
Autolite, Champion, and NGK are three good brands for spark plugs in our Wranglers. Just know to avoid single-tipped platinum (platinum on just one side of the gap) on newer 4.0 engines with the coil rail ignition systems. Conventional, double-tipped platinums, and iridium tipped are good in all model years and engine types. Single-tipped platinums are good in earlier 2.5 and 4.0 engines with a distributor cap and individual spark plug wires.
 
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Zach O'Neill

Zach O'Neill

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Those are fine, you just have to change them every 30K miles or so.

The Autolite double platinums will go about 100K mi and the iridiums about 200K or so.
I doubt I'll ever do 30k miles with the current fuel prices over here hahah at the moment it's costing me £80 to fill which I think works out to be about 110 dollars , it's nuts compared to the small Chevy I had before that took £30 to fill the tank and lasted 250+ miles , but it was nowhere near as fun as the jeep
 
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Wranglerfix

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Ill need to look into this, I had taken it to a PCM specialist but he said he opened one in the past and they have a gel coating on them so there's very little to test without really knowing what your doing which involves shipping it back stateside. so I was hoping it would be something different. The guy had said most likely it could be something electrical or sensor related so was holding onto that hope. The other difficult part is finding replacements for an export
I am not sure that you have a pcm issue yet. There are no serviceable parts inside of that pcm and the gelled coating encapsulates in the heat until it malfunctions.

The codes/symptoms can be reset a number of times by disconnecting the Pcm. Is there any way of contacting the former owner to see if they have had any of the following symptoms:

A hard shift from 1st to 2nd when cold, high transmission temperatures, O2 sensors showing bad when good are a few.

Thanks,

Mark
 

Jerry Bransford

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Ill check the brand that was installed as soon as possible. Do you think in your opinion something as simple as an o2 sensor could cause such the variety of issues I've been experiencing?
Hard to say for sure but if they're Bosch I'd definitely be more than suspicious and immediately replace them with NTK or NGK.
 
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Zach O'Neill

Zach O'Neill

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I am not sure that you have a pcm issue yet. There are no serviceable parts inside of that pcm and the gelled coating encapsulates in the heat until it malfunctions.

The codes/symptoms can be reset a number of times by disconnecting the Pcm. Is there any way of contacting the former owner to see if they have had any of the following symptoms:

A hard shift from 1st to 2nd when cold, high transmission temperatures, O2 sensors showing bad when good are a few.

Thanks,

Mark
Thanks for your reply mark,
I've had a bit of contact with the previous
owner last year but not since then , from my understanding he only really had the jeep about a year and sold due to having a job change and needing higher mpg for commuting, so that plus the pandemic I doubt it was driven far in the past year, I've had the jeep for about 2 and a half months at the moment. Personally I've not experienced any high transmission temperatures , I presume signs of this would be ouders, gears slipping and hesitation ? That kind of thing ? I've not had anything like that. There is a bit of a roughness between 1 and 2 occasionally but I don't know if it's just cause I'm not used to autos , I've only driven manuals up till this, apologies I know it's not much help. I know the o2 sensors were replaced but this was done by a mechanic as I've got an invoice for it, so I presume it threw a code and they were changed without question. I'll definitely try and get in contact with him to clarify his side though
 
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Zach O'Neill

Zach O'Neill

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Hard to say for sure but if they're Bosch I'd definitely be more than suspicious and immediately replace them with NTK or NGK.
So I've climbed under the jeep today and it appears that only 1 post cat sensor was changed bank2 sensor2 , but it's an NTK one , and the plug is fully seated. The rest all appear to be NTK sensors also. I gave everything a good shake as someone suggested the cat may be loose but everything's snug and tight
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B00CB58C-AE90-4EDC-81E8-99587BAE4F91.jpeg
79035517-06A2-41A9-8AB4-15AA9C8B4912.jpeg
 
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williambmac

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Fucktard state of NJ
I doubt I'll ever do 30k miles with the current fuel prices over here hahah at the moment it's costing me £80 to fill which I think works out to be about 110 dollars , it's nuts compared to the small Chevy I had before that took £30 to fill the tank and lasted 250+ miles , but it was nowhere near as fun as the jeep
With there being a pub on nearly every street in Glasgow, I would find no reason to every need a vehicle while living there.
 

williambmac

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So I've climbed under the jeep today and it appears that only 1 post cat sensor was changed bank2 sensor2 , but it's an NTK one , and the plug is fully seated. The rest all appear to be NTK sensors also. I gave everything a good shake as someone suggested the cat may be loose but everything's snug and tight View attachment 302203View attachment 302202View attachment 302201
Aside from the one new O2 sensor the others are the originals. How many miles on your jeep?
 
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Zach O'Neill

Zach O'Neill

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Aside from the one new O2 sensor the others are the originals. How many miles on your jeep?
Hard to say for sure but if they're Bosch I'd definitely be more than suspicious and immediately replace them with NTK or NGK.
Do you think it's possible that the o2 sensors could me failing and just not throwing codes ? I'm guessing the only way to tell would be replacing them and seeing if there's a change. In my post I had said I didn't know if it's was something heat related as it had sat un driven for a while before I got it and I jumped straight in and drove for like 6hrs straight ? So I presume maybe that running for that long when it's not used to long journeys could have tipped them over the edge ?
 

JKP

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Aug 20, 2020
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Warner Robins GA
Thanks for all your help it's been a life saver, I'll try replacing the remaining O2 sensors and see what that does. If nothing else it'll save me doing it in the future anyway.
Disconnect the battery when you replace the plugs and O2s to reset the computer.

Then when you start it up it will not have any old codes or settings in memory.
 
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Zach O'Neill

Zach O'Neill

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Disconnect the battery when you replace the plugs and O2s to reset the computer.

Then when you start it up it will not have any old codes or settings in memory.
Thanks for the tip, it's really helpful having all this help. As I had said I went from a 2013 Chevy hatch back to the jeep and it needed no maintenance, so having to dive into it so soon it's been a real help having so many people that live and breath jeep on tap. It's just a pain it's a hard to diagnose fault
 
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JKP

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607
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Warner Robins GA
You will need a 7/8 socket or wrench for the O2s.

There is a special O2 socket with the side cut out for the pigtail.

However for removing the old ones, especially since yours appears to have seen salt, that socket may flex too much. You can either use a flare nut wrench in that case, or totally commit and cut the pigtails off the old O2s and then use a reg socket or box end wrench as I seem to recall the connector on these is too big to fit through a 7/8 box end.
 
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Jerry Bransford

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You will need a 7/8 socket or wrench for the O2s.

There is a special O2 socket with the side cut out for the pigtail.

However for removing the old ones, especially since yours appears to have seen salt, that socket may flex too much. You can either use a flare nut wrench in that case, or totally commit and cut the pigtails off the old O2s and then use a reg socket or box end wrench as I seem to recall the connector on these is too big to fit through a 7/8 box end.
X2, don't use the special 7/8" O2 socket with the slot milled into it for removing the old O2 sensors. It's not strong enough for that since they are normally seized into place by the time they need to be replaced, it's meant for installing new O2 sensors. Cut the wiring off from the old sensors first then use a normal 7/8 socket/box-end/open-end wrench as needed. You may need some extra leverage from a breaker-bar etc. to break them free, they can be TIGHT.
 
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Zach O'Neill

Zach O'Neill

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X2, don't use the special 7/8" O2 socket with the slot milled into it for removing the old O2 sensors. It's not strong enough for that since they are normally seized into place by the time they need to be replaced, it's meant for installing new O2 sensors. Cut the wiring off from the old sensors first then use a normal 7/8 socket/box-end/open-end wrench as needed. You may need some extra leverage from a breaker-bar etc. to break them free, they can be TIGHT.
You will need a 7/8 socket or wrench for the O2s.

There is a special O2 socket with the side cut out for the pigtail.

However for removing the old ones, especially since yours appears to have seen salt, that socket may flex too much. You can either use a flare nut wrench in that case, or totally commit and cut the pigtails off the old O2s and then use a reg socket or box end wrench as I seem to recall the connector on these is too big to fit through a 7/8 box end.
I guess its one of the joys of owning a tj in a country that grits its roads at the slightest hint of ice haha. The rest of the frame is actually remarkably clean and rust free, just the notoriously bad exhaust that's caught the worst of it. I had ordered an o2 sensor socket, but I had imagined that by the look of them they'd be insanely tight to get loose.