O2 Sensors

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discostu

Guest
Can I check the O2 sensors, 99DII 4.0 NAS, using handtools or a local parts store loaner/diagnostic tool?

Is there anything, other than bad gas or oil consumption, that will kill the O2 sensors without affecting anything else?
 

Hoot

Well-known member
Apr 19, 2004
234
0
52
Bloomfield twp, MI
im talking out of my ass a bit here since i have never actually mussed with my 02's but from my recollection of what i have read on DWEB there is an 02 located in front of the cats and one behind. If your cats are bad then you can end up with a bad rear 02. I have also read that some additves/engine cleaners/carbon cleaner type products are not exactly 02 safe and they can also send the 02's to an early grave.

again this is just what i have read and not from experience. im sure some other folks on here will pipe up and either verify or dispute what i said above.
 
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Disco Mike

Guest
How many miles are on your truck? Is your truck running poorly?
You can test the with an OHM meter but I don't know the ranges you would be looking for.
O2 sensors wear out mainly from anything that goes past them that can contaminate them, coolant, oil,some additives. Heat from mileage will slowly bring them down also.
If you are over 70,000 miles it is safe to say they are starting to loose some of their effectiveness and if you replaced them you would find some of the old power your truck used to have.
If you're OK with the way the truck is running leave them alone until you get a code then change them all out at once.
Mike
 
D

discostu

Guest
Thanks for the response. The disco has ~65K on the odometer gets marginal mpg and is sluggish. I have an ohm meter if anyone knows what the resistance should be.
 

Hoot

Well-known member
Apr 19, 2004
234
0
52
Bloomfield twp, MI
ok this may be way off but have you cleaned out your butterfly valve lately? it could be nice and gummed up and casing the performance to be a bit sluggish. also i cleaned out my MAF last week along with the electrical caonnections using electrical cleaner andi can honestly say Landy is definatley more responsive when i step on it. I mean the differnce is not like night and day but i can say it is noticible. if you are the type to notice small changes like that then give it a try.
 

curtis

Well-known member
Apr 20, 2004
1,545
0
Salt Lake City, UT
If you are not thowing and codes then why are you asking? The need to check the O2 sensors should be driven by symptoms. All I can see is that your acceleration is slugish. That aint a symptom of anything but Rover ownership.

Now that we got that out of the way, you will need a good OBD-2 scanner or software. The O2 sensors are only reliably checked vis the OBD-2 interface and the ECU. Try www.obd-2.com
 

Joey

Well-known member
Apr 19, 2004
976
0
Liberty Township, Ohio
Acually the O2 sensors will start to go bad, giving poor fuel economy and performance long before they throw a check engine light. Any good OBDII scanner will show the O2 sensor responsiveness. When they start to slow down it is time to replace them. Normally between 60k and 80k depending on driving style and type of fuel.
 
D

discostu

Guest
Thanx for all the input. I am heading to the parts store to buy some elecrtical supplies. I will see if they can check the response on the O2 sensors. I will also clean all the parts y'all suggested. Thanx again
 
D

dent

Guest
take it to a shop where they can hook it up to a obd reader and with that they can check if it's good or not. don't go buying anything till you have this done as it could be fine
take care
 

curtis

Well-known member
Apr 20, 2004
1,545
0
Salt Lake City, UT
Again - www.obd-2.com is the answer. I have used thier unit for almost three years on several different vehicles. Just going to the local Auto Zone or even a shop will only give you a snapshot of what is going on. The Car Code software tests *everything*, and gives you the ability to take the vehicle on a full drive cycle. It then saves it as a file that can be played back later as a tape to watch all of the data. All for less than $130...if you have a laptop.