97 TJ Running Rough in Reverse and 4WD

[Dustin97tj]

Put 4new plugs in to day and all so 5 wires and d cap with new button still running ruff in reverse and in 4x4 throwing codes 12,27,21,11,21 any help.going to probably move on to o2 sencers later in the week may be take cat and muffler off replace with o2 pipe piece, and turbo tube?

 

[Dustin97tj]

 

[KCsTJ]

I would replace the upstream 02 sensor with the NTK #23506 02 sensor.
That should take care of engine code 27 and may even take care of your #21 codes as well.

 

[Dustin97tj]

Thats what i was thanking ,today unhooked battery for a wile to clear codes then try the o2 sencer, ive herd that there real finicky about what brand u use ,Bosch, nkg,? Any thoughts

 

[KCsTJ]

Thats what i was thanking ,today unhooked battery for a wile to clear codes then try the o2 sencer, ive herd that there real finicky about what brand u use ,Bosch, nkg,? Any thoughts

Yes. See thread #3. NTK #23506. Use only this sensor for your upstream sensor. Using any other brand or part number will just bring more misery.

 

[Dustin97tj]

Well didn't get to parts stor today but called them about the upstream o2 sencer auto plus our local patrs store which are really good about finding parts said that thay sold desno o2 sencers which were oem parts ? What yall are saying is nkt is that right or nkg 23506 ?

 

[Dustin97tj]

So im guessing code 27 which says soming about injectors ,might start from o2 sencer just trying to diagnose and whats your thoughts on upgrading injectors to a 4 hole injector?

 

[KCsTJ]

Heres a pic of my spare.

Get this one and only this one for your upstream 2.5L sensor.
@Dustin97tj How many miles on your engine?

No need to switch to 4 hole injectors. The 02 sensor makes sure the proper air/fuel mixture is maintained in the proper ratio.
Your worn out 02 sensor could be making the PCM think the injectors are bad.
You will know within a few minutes of installing the above sensor.

 

[Dustin97tj]

Cool thanks ill give it a try and let u know

 

[Chris]

X2 to all of the above! Let us know how it goes.

Also, you may find this thread handy: The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

 

[Dustin97tj]

Heres a pic of my spare.
View attachment 63044
Get this one and only this one for your upstream 2.5L sensor.
@Dustin97tj How many miles on your engine?

No need to switch to 4 hole injectors. The 02 sensor makes sure the proper air/fuel mixture is maintained in the proper ratio.
Your worn out 02 sensor could be making the PCM think the injectors are bad.
You will know within a few minutes of installing the above sensor.

130,000 miles

 

[KCsTJ]

We need to know the brand and part# of the 02 sensor you purchased then we can address the reverse, etc issues.
Also the type of transmission

 

[Jerry Bransford]

The engine has no way of knowing nor does it care if the Jeep is in Reverse or in 4x4.

 

[Dustin97tj]

I thank i have found the problem its in the wireing harness, now its to find a wiring harness lol

 

[KCsTJ]

I thank i have found the problem its in the wireing harness, now its to find a wiring harness lol

May I guess, you found a worn spot in the wire loom at the rear of the engine, near the firewall ..??
That's a common area for wire abrasion on these jeeps.

 

[Dustin97tj]

Yea neer the battery i was messing aroung with the wireing harness were some plugins were and it started missing like it does in reverse and i was smelling unburn gas ? Replace wiring harness or try to find the wire thats bad ,may be a wire or plug in