my 97 dx is throwing a code for the upper oxygen sensor... but here's what's up.

In the winter the code first happened and my car started running like **** because the exhuast manifold cracked between the second and third cylinder and so i got a header on ebay because it was way cheaper than everything else. But when i put the header on, i removed the catalytic converter and moved what was the lower oxygen sensor into the upper position. Since then i've gotten an oxygen sensor from on ebay and just put that in the lower position, and cleared the code but it still came back. So i'm thinking of just switching the oxygen sensor's to see if that matters at all, but idk why not having a catalytic converter would throw a code for the upper oxygen sensor... so any insight you guys have is appreciated

 

I don't think the upper and lower sensors are interchangible.

 

The lower or after cat sensor measure the efficiency of your converter.

 

You're always going to get the lower sensor code because you're running with no converter. Might as well not install a lower sensor at all. The upper sensor controls your fuel mixture so it's important to have it working even if you don't care about pollution.

 

thats the thing though... is that it's not throwing a code for the lower one

 

Were you throwing a code before you replaced the cracked manifold? If not, your old one still can be good.

 

ha, the old oxygen sensor was imploded... it looked like someone took a hammer to it.

but i just put the new oxygen sensor i got from ebay into the upper position, and put a plug in the lower sensor's position... after i cleared the codes it came up with a code for the lower oxygen sensor, but not the top one.

THis leads me to believe that if i take my lower sensor and extend the wiring and put it back in the lower position it might clear that code... since the code wasn't there when the other sensor was in the lower position... even though i don't have the catalytic converter in. i'll post once i get this done

 

definitely, primary is air/fuel ratio, secondary is cat efficiency, the DX situation (that alot of ppl are in, including you and myself) kind of sucks. You'll need to put the primary sensor back in the top and the as for hte secondary sensor, get an o2 simulator, thats the only way you wont throw a code. Even with an o2 sensor extended, you'll still throw a "cat efficiency" code, because theres no cat now, so the ECU is thinking the cat isnt doing its job good enouhg (obviouslY)