Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.

computer keeps reading o2 sensor. swapped out twice. rough idle getting worst. help.

Thread Tools
 
Search this Thread
 
Old 01-25-2022, 03:59 PM
  #61  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by Dave51

BTW are you running in "open loop" now?
Sorry that was when I thought you were running with sensors disconnected.

Things are moving fast here!
Old 01-25-2022, 04:03 PM
  #62  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

I think you need to probe O2 signal wires at the PCM to see how much volts you got (which I think is too much). Got the schematic?

And expose the O2 sensor signal wires all the way back to the PCM, or cut it and run a sister to the PCM.
Old 01-25-2022, 04:05 PM
  #63  
Junior Member
Thread Starter
 
fr3dbilli3's Avatar
 
Join Date: Jan 2022
Location: New York
Posts: 52
Likes: 0
Received 7 Likes on 7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 6L
Default

Originally Posted by Dave51
And



So I really can't see any reason why it wouldn't work fine.

BTW are you running in "open loop" now? Can you generate O2 waveforms with your software?

no unforunately i cant. im running a bafx wifi obd2 scanner with the obd fusion app but i want to try to get something a bit more official, this thing is quite janky

i just remmbered that i left something out on my latest update.

after installing the proper back o2 sensor, i cleared my code and started her up, she sounded great at first and eventually, after a couple moments and getting to 210, she started to sputter and eventually stalled out, before stalling, the little round evap leak detection thing started sounding off again, i heard some clicking but nothing loud enough to not reach to listen to.

Old 01-25-2022, 04:18 PM
  #64  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by fr3dbilli3
after installing the proper back o2 sensor, i cleared my code and started her up, she sounded great at first and eventually, after a couple moments and getting to 210, she started to sputter and eventually stalled out, before stalling, the little round evap leak detection thing started sounding off again, i heard some clicking but nothing loud enough to not reach to listen to.
Yeah, it went to closed loop, started picking up oddball O2 sensor voltage and that was that.

Hang on to this:


Old 01-25-2022, 04:24 PM
  #65  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Just slash in a new signal wire.
Old 01-25-2022, 04:30 PM
  #66  
Junior Member
Thread Starter
 
fr3dbilli3's Avatar
 
Join Date: Jan 2022
Location: New York
Posts: 52
Likes: 0
Received 7 Likes on 7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 6L
Default

Originally Posted by Dave51
Just slash in a new signal wire.

this sounds like quite the thins mate. this is when i miss my 91' volvo haha. i'm trying really hard not to cave as i really want to figure out this problem myself but for something like this i'm going to need to watch a video or something.
Old 01-25-2022, 04:35 PM
  #67  
Senior Member
 
exasemech's Avatar
 
Join Date: Sep 2016
Location: North East USA
Posts: 693
Received 342 Likes on 235 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by Dave51
Yeah kinda like printer cartridges.
actually the reason car manufacturers do stuff like that is to reduce the likelihood that things will be hooked up wrong on the assembly line. It's known as human factors engineering. .
Old 01-25-2022, 04:36 PM
  #68  
Junior Member
Thread Starter
 
fr3dbilli3's Avatar
 
Join Date: Jan 2022
Location: New York
Posts: 52
Likes: 0
Received 7 Likes on 7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 6L
Default

in the meantime im going to test the fuel injectors and order the proper o2 sensor to replace it with a ntk. i'm waiting on a 4 hole fuel injector kit as well as jeepcables big 7. not that this is going to solve my issue but it will feel godly if it did.

still waiting on a response as to if those voltage numbers i was getting earlier are where they are supposed to be? and if i'm supposed to be getting anything when testing the heater circuits.

see below;

Originally Posted by fr3dbilli3
resistance was consistent throughout. i’m only working with a multimeter at the moment so i wasn’t able to connect a 9 volt battery.

i will run to the hardware store and see if they have something to connect them

in the meantime. i tested the the o2 sensor connectors again and am getting a 3.8-4.0 reading when testing on the following setting while the car engine is on but both o2 sensors disconnected



the gal lending a helping hand ofcourse

please note that the reading i’m getting is coming from connectors 3-4. when testing 1-2 my multimeter reads 0.0


are these readings good?

freeze frame mentioned open loop and a diagnostic tech told me to continue with testing the o2 sensors although CEL disappeared
Old 01-25-2022, 04:38 PM
  #69  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

OK well this will clarify the wire colors you looking for:


Old 01-25-2022, 04:43 PM
  #70  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by fr3dbilli3

still waiting on a response as to if those voltage numbers i was getting earlier are where they are supposed to be? and if i'm supposed to be getting anything when testing the heater circuits.
It's that's from a signal wire then it's probably shorted to a heater wire.

Old 01-25-2022, 04:51 PM
  #71  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by fr3dbilli3
and if i'm supposed to be getting anything when testing the heater circuit
Yup 12V.
Old 01-25-2022, 04:53 PM
  #72  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by Dave51
It's that's from a signal wire then it's probably shorted to a heater wire.
Or maybe a 5V wire somewhere along the line.
Old 01-25-2022, 04:56 PM
  #73  
Junior Member
Thread Starter
 
fr3dbilli3's Avatar
 
Join Date: Jan 2022
Location: New York
Posts: 52
Likes: 0
Received 7 Likes on 7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 6L
Default

im just going to follow those suckers all the way back to the pcm and hope that i find a broken wire somewhere. do those cables go into the car? as in do i have to take off the dash and all that jazz to follow the wiring?
Old 01-25-2022, 04:58 PM
  #74  
Junior Member
Thread Starter
 
fr3dbilli3's Avatar
 
Join Date: Jan 2022
Location: New York
Posts: 52
Likes: 0
Received 7 Likes on 7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 6L
Default

Originally Posted by Dave51
Yup 12V.
oh yea so then theres definitely a shorted wire somewhere, from what i recall, and for both front and back sensor connectors, the heater circuit needles on the car connector was giving me 0
Old 01-25-2022, 05:05 PM
  #75  
CF Veteran
 
Dave51's Avatar
 
Join Date: Jan 2017
Location: Connecticut
Posts: 3,287
Received 372 Likes on 332 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by fr3dbilli3
those cables go into the car? as in do i have to take off the dash and all that jazz to follow the wiring?
Nah, it comes out of the other side of the fuel injector rail and curls around. Maybe 6 feet.


Quick Reply: computer keeps reading o2 sensor. swapped out twice. rough idle getting worst. help.



All times are GMT -5. The time now is 11:36 AM.