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o2 sensor help!

  #1  
Old 10-26-2018, 05:58 PM
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Default o2 sensor help!

I cannot find where my upstream o2 sensor is! I've looked everywhere and I've even looked online all over..Im trying to fix it myself because I don't have money to get it fixed..I have an 04 with a 3.8 engine
 
  #2  
Old 10-27-2018, 06:15 AM
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Location: Isanti, MN
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There are 2 oxygen sensors on your car . One is located on the backside of the engine where the exhaust leaves the engine.(upstream) and the other is located next to the catalystic convertor in the exhaust pipe(down stream). Good luck .
 
  #3  
Old 10-27-2018, 10:27 AM
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Originally Posted by Jeffs02rwdSS View Post
There are 2 oxygen sensors on your car . One is located on the backside of the engine where the exhaust leaves the engine.(upstream) and the other is located next to the catalystic convertor in the exhaust pipe(down stream). Good luck .
thanks! I hope that's the right one? the guy that looked at it said it's the one before the cadilac converter
 
  #4  
Old 10-28-2018, 07:51 AM
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Originally Posted by hfsitsshay View Post


thanks! I hope that's the right one? the guy that looked at it said it's the one before the cadilac converter
The one nearest to the cat is the downstream. The upstream is basically IN the rear exhaust manifold. Certain on this.

Its difficult to even see unless you rock the engine forward. You CAN see it if you know what youre looking for but still can be hard to find.
 
  #5  
Old 10-28-2018, 12:15 PM
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This drawing is a nice shot of it (looking straight at the back of the engine from the firewe all side).
 
  #6  
Old 10-28-2018, 03:44 PM
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Originally Posted by wht02monte View Post
The one nearest to the cat is the downstream. The upstream is basically IN the rear exhaust manifold. Certain on this.

Its difficult to even see unless you rock the engine forward. You CAN see it if you know what youre looking for but still can be hard to find.
I've never had a problem seeing it. Granted, I don't have the secondary AIR injection system (which is primarily for California emissions). That may make it a bit trickier lol.

 

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