xj o2 sensor complications

gboroxj

Active Member
Joined
Jan 24, 2010
Location
Greensboro
97 jeep cherokee sport. 4.0l. i have been looking for a solution to my problem for a while. ok well both o2 sensors have blown. i changed them the first time and got code turned off... came back about a week or two later. so went and exchanged them and they blew again in about a week or two. this was about 4 months ago.. i have since given up and just live with my check engine light. but within the last two months or so the light will randomly come on and off for about a week at a time each way. but has been on for about the last three weeks it has constantly been on again. also has what i refer to as a back fire, it happens in the first minute or two of starting it in the morning and only happens for about 5 to 10 seconds. the engine acts as if it is not receiving gas and will make this poping noise if i press accelerator. if i let it idle it will some how get itself worked out and be fine. i think it is really just the fact that no gas is getting into the cylenders and causing a misfire. i am looking for a solution because it is almost time for an inspection and wont pass in current state. i do not even know where to start and have looked about every where you can think for a solution. any help will be greatly appreciated. thanks aaron snider
 
nope i have a specter cold air intake (cheap-o) for the main hose and the one for the top of the valve cover i just have a small cone filter on. those are the only lines that ran off the intake if i remember correctly
 
I agree... If you can set it back to stock, try that. I have had a lot of trouble w/ aftermarket intakes messing up O2 sensors on both the 4.0 and 2.5 Jeep motors. Seems like the newer motors really need the emissions sensors to be spot-on.

Of course, the O2 sensors are not known to be the most rugged pieces either.
 
What codes actually set? You shoul dbe able to do basically anything in front of the intake and have no negative effect on the 02 performance.
If you're getting o2 heater codes, then that has nothing at all to do with the mixture. Also, what voltages are present on the downstream sensor? Its signal will indicate where the issue lies.
BTW- I'm a Jeep driveablilty tech. I'll help ya all I can.
 
I still have stock intake and will try that out... Should I swap out sensors again when I do it... I remember it shot 4 codes.. Two for each sensor I'm not sure what codes were but I remember something about a high voltage i'll get codes re checked. Thanks
 
went and got my codes checked and got one about the 1st(front) o2 sensor and something to do with heat. also had a code reading cylinder 5 misfire. any ideas?
 
gboroxj said:
went and got my codes checked and got one about the 1st(front) o2 sensor and something to do with heat. also had a code reading cylinder 5 misfire. any ideas?
Click to expand...

If you're referring to an oxygen sensor heater circuit, you can almost bet on the sensor itself being failed. Don't try to save some coin with an aftermarket oxygen sensor, there are numerous threads out there about them not working effectively. Go with one from the dealer. I see it frequently at my dealership where a customer had an aftermarket oxygen sensor installed, just to have us replace it with a MOPAR one.

Cyl 5 misfire? Could be a bunch of things. From poor state of tune to valve springs (which is a possibility). Ensure the ignition side is good. Go with Champion plugs at 0.035 and good wires.

That should get ya going in the right direction.
 
how much do these sensors cost? do they have warrenty... do i need to swap the stock air intake back in... greensboro no longer has a jeep dealership where can i get them locally? also do not want to mess with dealership labor fee of an hour of pay to screw a sensor in and plug it up. thanks though your pointing me in the right direction
 
Crown Chrysler Dodge

877-492-6655

Its off wendover.

Thats the parts phone #.
 
well im not sure what happened but i disconnected the neg on battery took out the spark plug for cyl 5 and put it back in and poped the cord back on it hooked the battery back up turned it on and drove it for a solid 15 minutes and by some type of magic or someone was looking out for me i have no check engine light and a strong running motor... did not change o2 sensor... dont know why its not throwing a code... much thanks to all who gave me their input. aaron snider
 
Drive some more. All the monitors may not have turned back on yet. Also if you have any exhaust leaks before the O2 sensors this will cause them to read out of range. You may want to look into that.
 
i have no exaust leaks... i changed everything out (minus cat) from the block to the rear bumper and all is welded. i think i have it to where i can pass an inspection though which is my main concern at this point
 
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