Codes for O2 sensor and engine speed circuit

[Bbrayden85]

So i just bought my ‘97 tj about a month ago maybe. Its the 2.5. I test drove it and everything seemed good. No warning lights. Ran good. Nothing out of the ordinary. I drove it home fine and even drove it to work one day about 12 miles there. I tried driving it to work again the day after the next and i made it a little over a mile down the road when it started sputtering and had basically no power and idled at like 250 rpm. Right before this it threw a check engine light for an o2 sensor and engine speed circuit.

Ever since it has been doing this basically right before it gets to temperature or right when it gets to temperature. I have had a few ideas i started with replacing the crank position sensor. No change and i also thought it could be the o2 sensor but they are brand new it looks like. It idles perfect but when driving it sort of lacks power and has spurts where it has power and then doesn’t. St one point it stayed idling very poorly even when cold but i unhooked the battery for a couple minutes and it idled perfect right after.

I am really disappointed because i was excited to enjoy this jeep. If anyone has encountered this or have any ideas please let me know. I have a part coming so i can check fuel pressure and i also heard the 5v circuit that comes out of the pcm can quit working. Could this be a cause? I just need some ideas to point me in the right direction. Thanks

 

[Bbrayden85]

FYI it is entirely undriveable during this time and can only inch forward by feathering the clutch to get me off the road. If you hit the throttle it will go up to maybe 2000 rpm and then just crap out and throttle basically just makes it entirely unhappy.

 

[Bbrayden85]

The first half is the jeep idling and the second half is me pressing the gas

 

[Juggernaut]

I would judge an O2 sensor by its looks. If it has an O2 sensor code, then replace the O2 sensor with a known good one and good brand. It does sound like an O2 sensor problem. Your jeep is in open loop until it warms up, then it switches to closed loop where it relies on the O2 sensor feedback. This is where you start experiencing problems.

Unhooking the battery also resets the adaptive memory and fuel trims - again pointing towards an O2 problem.

 

[Juggernaut]

That should say wouldn’t judge!

 

[RobertJ]

They may not have used a proper O2 sensor even if they are new. NGK (OEM manufacturer) sensors are preferred for our motors and other brands can cause severe drivability issues.

 

[T Crawford]

The another suggestion could be a possible plugged catalytic converter

 

[Chris]

How can you judge an O2 sensors condition by the way it looks?

Seriously?

First off, if you have no record of when the O2 sensors were replaced, you need to replace all of them with NGK sensors. See this thread for more details: The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread. O2 sensors are general wear-and-tear maintenance items and need to be replaced every 80k miles or so to keep your engine running optimally. In addition, DO NOT use any sensors other than NGK or you will have issues. FYI, NGK sensors are the OEM sensor that Mopar uses.

If that doesn't get rid of your issues (which sound O2 sensor related), then my guess is you have a short somewhere in the wiring, in which case you'll need to spend A LOT of time tracing wires, looking for breaks in them.

 

[Goatman]

Even a brand spankin' new 02 sensor can be bad. It sounds like as soon as the engine switches to a closed loop system (reaches operating temp and switches to reading sensors) is the point where it scraps out. This acts like an 02.
Just my opinion.

 

[DoOver]

I have the 4.0 liter but, I had a similar experience recently. Started out throwing O2 sensor codes. Replaced them but, codes kept coming. Mostly occurred after it got hot (long drives with A/C on or hot afternoons). Eventually turned into engine bogged down. Barely got to 35 mph. Turns out, my cats were all broken apart and clogging the exhaust creating back pressure.
All good since the cats were replaced.

 

[Bbrayden85]

How can you judge an O2 sensors condition by the way it looks?

Seriously?

First off, if you have no record of when the O2 sensors were replaced, you need to replace all of them with NGK sensors. See this thread for more details: The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread. O2 sensors are general wear-and-tear maintenance items and need to be replaced every 80k miles or so to keep your engine running optimally. In addition, DO NOT use any sensors other than NGK or you will have issues. FYI, NGK sensors are the OEM sensor that Mopar uses.

If that doesn't get rid of your issues (which sound O2 sensor related), then my guess is you have a short somewhere in the wiring, in which case you'll need to spend A LOT of time tracing wires, looking for breaks in them.

You dont have to act that way about it dude. Im just explaining my scenario. The o2 sensor looks new and shiny unlike an old rusty one

 

[Bbrayden85]

Even a brand spankin' new 02 sensor can be bad. It sounds like as soon as the engine switches to a closed loop system (reaches operating temp and switches to reading sensors) is the point where it scraps out. This acts like an 02.
Just my opinion.

I will look into the o2 sensor and see about ordering new NGK ones

 

[Bbrayden85]

Where can i find ngk o2 sensors?? All i can find is the ntk.

 

[tworley]

Click on the links in the thread that Chris posted.

 

[Bbrayden85]

I replaced both my sensors with ntk ones. The old ones were not branded or had a part number stamped on them but they were different from the ntk ones. The problem seems to have vanished and my jeep now runs very good. Thank you guys

 

[SkylinesSuck]

Where can i find ngk o2 sensors?? All i can find is the ntk.

Same same

 

[Bbrayden85]

Same same

https://wranglertjforum.com/threads/the-official-jeep-wrangler-tj-oxygen-o2-sensor-thread.4068/This is a post by chris. It shows every o2 sensor for every tj year and engine. If you click the part number it will take you to the amazon product or you can just lookup the part number. Ntk is the same as ngk and that is what icwent with

 

[SkylinesSuck]

https://wranglertjforum.com/threads/the-official-jeep-wrangler-tj-oxygen-o2-sensor-thread.4068/This is a post by chris. It shows every o2 sensor for every tj year and engine. If you click the part number it will take you to the amazon product or you can just lookup the part number. Ntk is the same as ngk and that is what icwent with

That's what I said? NTK = NGK. Same same.