check engine light

wrangler00

wrangler00

Active Member
Joined
Jun 16, 2009
Location
morganton
aight so i had a check engine light come one about 8 months ago when and had it checked out and come to find out it was the o2 sensor changed the sensor and the check engine came back on looked around under the hood couldnt find out what could be wrong then looked under the dash and found a wire that was rubing the support for the steering shaft changed the o2 sensors and turned the check engine light back off about 45 mins later the the check engine light came back on went and had it checked out it was another o2 sensor and throttle position sensor but it was only the upstream o2 sensor this time and not both changed both bad sensors again and had the check engine light come back on the next day the mechanic said it may be the computer does anyone else have any ideas about what it could be and how i could fix it i need to get this pile inspected its a 2000 jeep wrangler thanks for any help and sorry its so long
 
No offense, but it was hard to read your post with no punctuation; but I think you said you have changed the O2 sensor(s) multiple times and the CEL still comes on.
You're not putting any type of grease or sealant on the O2 sensor connector are you? The O2 sensors have to be able to get fresh air to perform their oxygen comparison and they get the fresh air thru the connector.
It could also be an indication of a bad catalytic converter.
 
i dont believe in punctuation but anyway i went to the muffler place and had the cat checked and they said it was fine and the only grease that is on it is the grease on the threads that came on it and it is saying the 02 sensor is shorting out
 
kyle you need to get the o2 sensor from the jeep place there higher in price but id say thats what it is ive heard over ppl have the same problem
 
so you guys think it is a defective product and not the jeep right? but ive had like 4 of them and ive got them from 2 different places but it would make sence tho because its is a high voltage short at least thats what the diagnoustic at the shop said but tomarrow i will got the jeep place and get the code for wwildman and ill try another o2 sensor from the jeep place and ill keep yall updated
 
#1...seriouslyyourpostsarehardtoreadwithoutsomesentenccestructureandpunctuation.

Check the wire coming off the O2, make sure it is not nicked or cut..it is possible to get voltage bleed or less than complete shorts to cause some crazy stuff.

If no wiring issues there are only 3 possibilities as I see it.
1- ECM this should be able to be diagnosed by pulling a data file and comparing it with metered readings
2- You are getting crappy O2 sensors. OEM cost more for a reason GENERALLY speaking.
3- An engine problem (most likely could be caused by another sensor or modification) that is causing the sensors to see large quantities of raw fuel or oil or coolant.
 
ive got the same problem going on. changed both O2 sensors and was told a cracked exhaust manifold could be the problem. looked and saw a huge crack, changed the manifold and still having the same problem. next on my list is the Cat. changing that out this weekend
 
I looked at it today to try see what the issue is. Looks like it is running real rich, Lots of blacking on the o2 sensor after just a few hours. Like the caked on kind you can rub off with your finger. He says hes getting poor mpg also >10mpg. So my thinking is the rich condition is throwing the o2 code.

So the question is what all can cause it to run rich? Has a new TPS sensor. I going to swap in my MAF and MAP sensors (which I know are good) to see it that helps or solves the issue. Checked all vac lines for leaks, also it will rev high when a vac line is pulled. So I feel like the vac lines are good.

Any other suggestions or ideas. I will have him check the manifold for cracks, haven't checked that yet.

Thanks
 
There were no cracks in the manifold. I went to the auto store and got some sea foam and injector cleaner. Someone told me that maybe its because the injector is hung open giving to much gas and making it run rich. Which in turn would make the o2 sensor do its job and relize something is wrong and making it throw a code. Maybe this might fix it lets hope so
 
also if the o2 is bad it will cause it to run rich...


chicken or egg
 
burrellsjeep said:
Thanks Ron for the great insight....
Do you think it would still run rich for a while once the new 02 sensor is installed or should it correct it self pretty quick, Just thinking he may not have drivin it enough after installing the new 02 sensor
Click to expand...


not sure if that is smart ass or serious :lol:

but to better explain, the whole purpose of the O2 sensor is to determine the disolved oxygen content in the exhaust gas and lean or richen the fuel delivery to achieve stoich.

iot should correct itself immediately if it is getting good data. But if the exhausst system is full of carbon and unburned fiuel it needs to be cleaned up first.

I am no (new) Jeep guy but on a chevy I would want to see the data from a laptop plug in and see what it is reading and compare that to an a/f meter stuck in the tailpipe.
 
anyway to tell if you are in closed loop or open?
 
SkyHiK5 said:
not sure if that is smart ass or serious :lol:
but to better explain, the whole purpose of the O2 sensor is to determine the disolved oxygen content in the exhaust gas and lean or richen the fuel delivery to achieve stoich.
iot should correct itself immediately if it is getting good data. But if the exhausst system is full of carbon and unburned fiuel it needs to be cleaned up first.
I am no (new) Jeep guy but on a chevy I would want to see the data from a laptop plug in and see what it is reading and compare that to an a/f meter stuck in the tailpipe.
Click to expand...

Thanks

And it was a little of both :lol:
 
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