02 Sensors, need help quick.

Iwantmymarkback

Iwantmymarkback

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Me and a close family friend are going to replace the 02 sensors in my car. What we need to know is where the 02 Sensors are, and how many of them there are. Sometimes I have heard that there are three, or maybe four? If anyone can help me, maybe show me a diagram.. that would be great. Thanks for all of your help.
 
don't have a diagram but you have 4, one one each header (I believe just after all the pipes come together), and one just after the cats. I know the ones by the cats are really easy, the others I'm not too sure about.
 
OBD I cars have 2, before the header. OBD II cars have 4. 93-mid 95 has only 2.
 
Positive?

Is everybody positive that there are four O2 Sensors in the 1997 model? It is extremly important to find this information out. And is it usually just one 02 sensor that would make sense to replace? Or is it just worth it to replace all four, or two?

Can anyone tell me what OBD means and such? Thanks
 
Iwantmymarkback said:
Is everybody positive that there are four O2 Sensors in the 1997 model? It is extremly important to find this information out. And is it usually just one 02 sensor that would make sense to replace? Or is it just worth it to replace all four, or two?

Can anyone tell me what OBD means and such? Thanks
Click to expand...


On Board Diagnostic. It's an engine control / emissions control standard. Cars 1996 and later were mandated by law to employ OBD - II, an "upgrade" over the previous standard.
 
Iwantmymarkback said:
Is everybody positive that there are four O2 Sensors in the 1997 model? It is extremly important to find this information out. And is it usually just one 02 sensor that would make sense to replace? Or is it just worth it to replace all four, or two?

Can anyone tell me what OBD means and such? Thanks
Click to expand...


Yes you have 4. Two before the cat (up stream) and two after the cat (down stream) Should you need to change one up stream o2 sensor, it makes good sense to change them both. They ought to be changed out every 80k.
 
Honestly dude, I just bought all four 02 sensors, and now i look like the moron. Thanks a lot for everyone else who really HELPED me. You really should have said that before hand when I asked the first time instead of just saying yes you have 4 o2 sensors. Now I look like the dick.
 
Iwantmymarkback said:
Honestly dude, I just bought all four 02 sensors, and now i look like the moron. Thanks a lot for everyone else who really HELPED me. You really should have said that before hand when I asked the first time instead of just saying yes you have 4 o2 sensors. Now I look like the dick.
Click to expand...


No you don't look ike a Dick. Do all of the O2 sensors have the same part number? If you had gotten them at a reputable parts store, they should have your car's info on the computer and given you the two for before the cat and the 2 after the cat.

Note: http://www.rockauto.com/catalog/x,carcode,1188569,parttype,5132

Upstreamand downstream are BOTH listed as Oxygen sensors.
 
Frogman said:
I'm not trying to, but if he gets FOUR O2 sensors and replaces the rears with O2 sensors, the car won't run right.
Click to expand...

True if he puts in two oxygen sensors that are for the front. Not two oxygen sensors that are meant for the rear.


taken from: http://www.corner-carvers.com/wiki/index.php?OBDII and O2 Sensors Explained

"The difference in front to rear O2's is explained by the way the cats work. The front O2's operation is verified exactly as described above. The rear O2's have different operational parameters because of the catalyst. During normal closed loop operation, high efficiency cats have an oxygen storage capacity. Because of this, the rear O2's will switch at a much slower rate than the front units. As a catalyst deteriorates, the oxygen storage capacity will diminsh and the switching frequency of the rear O2's will increase and begin to closely match that of the front O2's. Once that ratio of front to rear switching frequency passes a certain threshold the computer thinks the CAT is not effective and trips the MIL."
 
they are tech called "cat moniters" behind the catsand they are used to see if the cats are failing, ford reflashes pcm's all of the time to broaden the tolerances for the cat's but all they will do is trip a light everything will run fine
the same as torque said but easier to follow
rember the k.i.s.s. rule
Keep It Simple Stupid
i live by this rule at work
 
chickenviii said:
they are tech called "cat moniters" behind the catsand they are used to see if the cats are failing, ford reflashes pcm's all of the time to broaden the tolerances for the cat's but all they will do is trip a light everything will run the same
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And if yiou are in an emmisions area, you will fail because you have a MIL/ trouble code.
 
no emissions here so ram out them cats ang get them mil eliminators but im too lazy and poor so i leave the stock 126k exhaust alone
 
Iwantmymarkback said:
Honestly dude, I just bought all four 02 sensors, and now i look like the moron. Thanks a lot for everyone else who really HELPED me. You really should have said that before hand when I asked the first time instead of just saying yes you have 4 o2 sensors. Now I look like the dick.
Click to expand...

Or I can really help you look like a dick.;) j/k

I posted this the other day so a search on the LVC may have revealed this info to you in a timely manner.....

On the Corral there is a guy selling them for $70.00 shipped for a set of 4.
http://www.corral.net/forums/showthread.php?t=809019

Just got mine today. Bought 2 sets. That is why there are 8 shown. Haven't installed them yet but I now he has only 8 sets left. I just bought another set for my Expedition a couple of minutes ago.

Again, I haven't installed them yet so performance (or even if they work for that matter) is an unknown.

o2 sensor 1 (512 x 384).jpg


o2 sensors 2 (512 x 384).jpg


o2 sensors 3 (512 x 384).jpg
 
Last edited:
torquemonkey said:
Upstreamand downstream are BOTH listed as Oxygen sensors.
Click to expand...

that was my point, you go to the parts store and tell them you need O2's they'll just ask before or after the cat, they categorize both under O2's
 
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