If you have ever wondered if there is any difference between the Upstream and Downstream O2 sensors; the answer is "yes"!
First difference:
Upstream Sensor is in the Exhaust Manifold Pre-Cat
Downstream Sensor is in the Exhaust Pipe Post-Cat
Second difference: (and most important)
There is a reason why the Upstream O2 sensor is about 2-3x more expensive than the downstream sensor. It is what tells your cars ECU when the AFR goes rich, stoic, or lean. This allows
your computer to advance or retard timing in order to prevent knock or detonation from occurring.
The Downstream O2 sensor is used to tell the ECU if the emissions system is working correctly... that's about all it does.
When you get your check engine light, nearly 90% of the time it will be the O2 sensor... (or so it seems, no real data to back that statistic up).
If the code is in reference to the Upstream sensor, then it is important to replace the sensor as soon as practical. Very important to avoid boost or WOT driving.
If the code is in reference to the Downstream sensor, then it is important to ensure that your Catalytic Converter is not fouled up and causing an excess restriction on your engines exhaust flow.
Hope this clears up any confusion as I found numerous forum sites stating that there is no real difference between the two except location, and as I used a new Downstream to plug the hole in my exhaust manifold (upstream) in order to get my car home the check engine light and Accessport state the Upstream sensor is bad, even after two ECU resets.
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I need to replace my upstream sensor and would like to use Denso on my '96 Accord DX. Is there a real difference between the two below? One says it is upstream and the other says it is downstream but they seem identical and the one that is downstream is cheaper. Is it just the wire lenght?
"Downsteam"
"Upstream"
I am Jack's...
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Most times that is correct. Any four wire will replace any four wire. The difference is in the computational data. The upstreams is basicly a baseline (set between two points) and the downstream is an efficiency report on the upstream converter system. Very basicly discribed mind you.
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Length of the wires and I think the connecter orientation is different as well. The sensors themselves are the same.
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So, what do you recommend? Since I have to replace the upstream one, just pay the extra ten bucks to make sure it will work?
How hard is splcing wiring on these things because the below one requires that and only costs $30.
Thanks for you fast help.
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@Ghostaccord, since you have an Accord '96, do you know if the connection portion is the same?
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The plugs should be the same. You could always extend, solder, and use the existing plug if you really had to. Otherwise an oxygen sensor is an oxygen sensor, just MAKE SURE you stick with a Nippon Denso one. Upstream is pre-cat, downstream is post-cat.
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Nice!
Giong with the one below. Hope it goes well. Need it for emission test in Cali.
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Quote:
Originally Posted by tekram
Good luck. I'll pray for you.. lololol I'm so glad I don't live in ****-fornia.
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Quote:
Originally Posted by NZXTInerTia
I'm so glad I don't live in ****-fornia.
Whoa whoa whoa whoa... easy there Mr Minnesota. The only snow blower a typical Californian may ever have to deal with is a hooker greedy with the cocaine
tekram if the O2 sensors don't come with shrink wrap, make sure to pick some up and use it before splicing on to make sure it is weather tight.
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Yall can keep your 110� summers and two seasons, F#@king Hot and F#@king wet. Those dumb communist car laws are just another bother!
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Quote:
Originally Posted by MAD_MIKE
Whoa whoa whoa whoa... easy there Mr Minnesota. The only snow blower a typical Californian may ever have to deal with is a hooker greedy with the cocaine
Quote:
Originally Posted by GhostAccord
Yall can keep your 110� summers and two seasons, F#@king Hot and F#@king wet. Those dumb communist car laws are just another bother!
Easy guys, Mike can go back to watching 90210 (in real life of course), and Mark can go back to drinking beer and being nice to everyone. I'll go die again in our 90deg and humid weather! Win win!
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Quote:
Originally Posted by tekram
So, what do you recommend? Since I have to replace the upstream one, just pay the extra ten bucks to make sure it will work?
How hard is splcing wiring on these things because the below one requires that and only costs $30.
Amazon.com: Denso 234-4209 Oxygen Sensor: Automotive
Thanks for you fast help.
I put that sensor in my accord 96 in the catalytic converter and reuse the old connector and work perfect...
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