O2 sensor issues?
#76
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
I still think you have to pull all the relays out of the block and put on new connectors because the existing connectors are in terrible shape so you don't know if they're conducting correctly; if the connections were correct there'd be no need for a jumper; and no matter which schematic you use I don't think Oxygen Heater Relay is supposed to have 6 wires.
#77
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Joined: Jan 2017
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
http://oljeep.com/parts_man/1990Jeep...viceManual.pdf
#78
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Joined: Apr 2018
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Which schematic are you using? Using the 1990 manual from cruiser's site and what your images show I think this one should be the right one:
I still think you have to pull all the relays out of the block and put on new connectors because the existing connectors are in terrible shape so you don't know if they're conducting correctly; if the connections were correct there'd be no need for a jumper; and no matter which schematic you use I don't think Oxygen Heater Relay is supposed to have 6 wires.
I still think you have to pull all the relays out of the block and put on new connectors because the existing connectors are in terrible shape so you don't know if they're conducting correctly; if the connections were correct there'd be no need for a jumper; and no matter which schematic you use I don't think Oxygen Heater Relay is supposed to have 6 wires.
The o2 relay schematic shows 6 wires.
The back side of the relay block looked bad because it had a bunch of dried up dialectric grease in it. Plus some of what looked like corrosion was actually the white connector keepers.
I do Agree though that it should be replaced.
That's a good point, the need for the jumper would not be needed. Unless there is an issue with the ignition switch.
#79
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Joined: Apr 2018
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I'm not sure if we can say that just yet, but testing the ignition switch is on Pages 8D-84 and 85 in the manual in case you don't have that already.
http://oljeep.com/parts_man/1990Jeep...viceManual.pdf
http://oljeep.com/parts_man/1990Jeep...viceManual.pdf
#81
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
So close I can almost smell it.
#82
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
o2 relay Pin #86 goes to pin #86 on AC relay. Wonder if that's a clue.
o2 relay pin#30 goes to ignition switch.
Maybe there's a way to test ohms on the ignition switch going to o2 pin #30 rather than removing the ignition switch. Major PITA just to look at the switch. It's likely good being I have no other issue.
I remove lower trim panel and got access to the ignition switch plug. Didn't see any signs of bad wiring or connections.
#83
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Joined: Jan 2017
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Let's collect our thoughts:
The O2 sensor gets warm when the engine is off?
Does the parasitic draw drain the battery?
The O2 heater wire has been traced to Oxygen Sensor Relay 30 and continues to be hot on its way to the ignition?
I still think the relay wiring has to be rebuilt but that's going to take time so perhaps we should look at a workaround...
relay Pin #86 goes to pin #86 on AC relay. Wonder if that's a clue.
o2 relay pin#30 goes to ignition switch.
Maybe there's a way to test ohms on the ignition switch going to o2 pin #30 rather than removing the ignition switch. Major PITA just to look at the switch. It's likely good being I have no other issue.
I remove lower trim panel and got access to the ignition switch plug. Didn't see any signs of bad wiring or connections.
o2 relay pin#30 goes to ignition switch.
Maybe there's a way to test ohms on the ignition switch going to o2 pin #30 rather than removing the ignition switch. Major PITA just to look at the switch. It's likely good being I have no other issue.
I remove lower trim panel and got access to the ignition switch plug. Didn't see any signs of bad wiring or connections.
...parasitic draw...
Does the parasitic draw drain the battery?
The O2 heater wire has been traced to Oxygen Sensor Relay 30 and continues to be hot on its way to the ignition?
I still think the relay wiring has to be rebuilt but that's going to take time so perhaps we should look at a workaround...
#84
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
That said the PO has done some electrical mods, so could something have been done at the switch?
Just sayin'...
#85
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Joined: Jan 2017
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Oh right.
How about this. Take the wire that's hot but shouldn't be, that goes to the ignition switch. Cut it. The ignition side should be hot. O2 Relay side should now be dead. Make sure the Oxygen Sensor Heater isn't hot anymore. Splice in a toggle switch and mount it on the dashboard as a kill switch.
How about this. Take the wire that's hot but shouldn't be, that goes to the ignition switch. Cut it. The ignition side should be hot. O2 Relay side should now be dead. Make sure the Oxygen Sensor Heater isn't hot anymore. Splice in a toggle switch and mount it on the dashboard as a kill switch.
#86
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Joined: Apr 2018
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I agree that that something needs done with the relays. There's a 90 at the junk yard going to grab it if its nice and clean otherwise will get the relay kit on amazon.
"The O2 sensor gets warm when the engine is off?"
Correct.
"Does the parasitic draw drain the battery?
"
Yes it does.
"That said the PO has done some electrical mods, so could something have been done at the switch?"
I would not doubt that the PO has done something up there. I did see another plug above the steering column right above the switch. Not sure if it actually goes to the switch, kinda hard to see. That video you posted shows that a burn could easily be missed without removing it.
With that said why stop there, I'll l just remove the sucker anyhow. Doesn't hurt for long.
By the way??? Seen it in forums before. What the heck is a PO?
"The O2 sensor gets warm when the engine is off?"
Correct.
"Does the parasitic draw drain the battery?
"
Yes it does.
"That said the PO has done some electrical mods, so could something have been done at the switch?"
I would not doubt that the PO has done something up there. I did see another plug above the steering column right above the switch. Not sure if it actually goes to the switch, kinda hard to see. That video you posted shows that a burn could easily be missed without removing it.
With that said why stop there, I'll l just remove the sucker anyhow. Doesn't hurt for long.
By the way??? Seen it in forums before. What the heck is a PO?
#88
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Joined: Apr 2018
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Dave,
Here is a thread on the naxja forum I chimed into when I originally found out I was having o2 sensor issues.
It starts on April 7th 2018. It goes on for a few pages and ends on Oct 9th 2018.
https://www.naxja.org/forum/showthre...or+test&page=7
Here is a thread on the naxja forum I chimed into when I originally found out I was having o2 sensor issues.
It starts on April 7th 2018. It goes on for a few pages and ends on Oct 9th 2018.
https://www.naxja.org/forum/showthre...or+test&page=7
Last edited by randy61; 05-21-2019 at 09:30 PM.
#89
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Joined: Apr 2018
Posts: 132
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Dave,
I have a revised plan.
There's a 90 at the Junk Yard.
Saturday I am going to clip the relay holder from it and bring it home to compare the wiring to mine. That way I can be sure that the relay wiring on mine is correct. If mine are really not correct than that could potentially save me from tearing my ignition switch out.
Also if the relay holder is in great shape I can splice it to my wiring and still have the original holder for the relays. Will be easier to mount it than it would be for the amazon relay holders.
If the relay holder isn't any better than mine than no loss.
It also has a new starter relay, mine looks old. And I can scarf the fusable links that go to the starter relay.
And I can grab the ignition switch from it easily being that the dash on it is all torn apart.
Bonus is that you can take a break for the rest of the week from all of your (much appreciated), help you have been providing me.
I have a revised plan.
There's a 90 at the Junk Yard.
Saturday I am going to clip the relay holder from it and bring it home to compare the wiring to mine. That way I can be sure that the relay wiring on mine is correct. If mine are really not correct than that could potentially save me from tearing my ignition switch out.
Also if the relay holder is in great shape I can splice it to my wiring and still have the original holder for the relays. Will be easier to mount it than it would be for the amazon relay holders.
If the relay holder isn't any better than mine than no loss.
It also has a new starter relay, mine looks old. And I can scarf the fusable links that go to the starter relay.
And I can grab the ignition switch from it easily being that the dash on it is all torn apart.
Bonus is that you can take a break for the rest of the week from all of your (much appreciated), help you have been providing me.
#90
CF Veteran
Joined: Jan 2017
Posts: 3,297
Likes: 375
From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Dave,
I have a revised plan.
There's a 90 at the Junk Yard.
Saturday I am going to clip the relay holder from it and bring it home to compare the wiring to mine. That way I can be sure that the relay wiring on mine is correct. If mine are really not correct than that could potentially save me from tearing my ignition switch out.
Also if the relay holder is in great shape I can splice it to my wiring and still have the original holder for the relays. Will be easier to mount it than it would be for the amazon relay holders.
If the relay holder isn't any better than mine than no loss.
It also has a new starter relay, mine looks old. And I can scarf the fusable links that go to the starter relay.
And I can grab the ignition switch from it easily being that the dash on it is all torn apart.
Bonus is that you can take a break for the rest of the week from all of your (much appreciated), help you have been providing me.
I have a revised plan.
There's a 90 at the Junk Yard.
Saturday I am going to clip the relay holder from it and bring it home to compare the wiring to mine. That way I can be sure that the relay wiring on mine is correct. If mine are really not correct than that could potentially save me from tearing my ignition switch out.
Also if the relay holder is in great shape I can splice it to my wiring and still have the original holder for the relays. Will be easier to mount it than it would be for the amazon relay holders.
If the relay holder isn't any better than mine than no loss.
It also has a new starter relay, mine looks old. And I can scarf the fusable links that go to the starter relay.
And I can grab the ignition switch from it easily being that the dash on it is all torn apart.
Bonus is that you can take a break for the rest of the week from all of your (much appreciated), help you have been providing me.
If you can find the part# of your harness bring it along. I've noticed the power line (11) in some documents is orange (like yours) and in others it's yellow. Don't suppose it makes a difference to the electricity. Probably just a year thing.
And if worse comes to worse (worst?) skip the holder entirely. Just put new insulated crimp terminals on the wires and leave the relays free-standing.