Air fuel problem
 

What’s up everybody. I’m having a prob with my evo that I need some more help with. So my buddy and I were gonna install an o2 yesterday and swap his old exhaust onto my car. The exhaust went fine until we got to the primary o2 sensor on o2 housing. The o2 sensor was stuck on the housing and we tried everything to get it off.

my friend tourched it to try and free it up but still no dice. So I decided I would buy a new sensor this week and put it on later. So we put the stock o2 housing and now the car runs like dog**** if you free rev in neutral. A/f gauge starts at 14 and sinks to 10 and the idle starts to get really bad. So my question is, is the primary o2 done for and I need a new one? Could him torching it possibly have killed it? Nothing else was messed with during the installation.

Yeah, thats possible it has been damaged.

The methods im familiar w/are applying the Blue Wrench to the o2 housing only making sure not to apply too much flame to the sensor itself. Let the housing cool a bit & then hit it w/some penetrant before apply a real wrench to the o2

Sounds like youve done the right thing in buying a new o2

Keep us posted please

Thanks! Yeah only thing I could really think of was that o2 sensor or maybe a boost leak has sprung up. I will update the thread when I fix it.

Torching the o2 shouldn’t cause too much as long as you didn’t torch it red hot. The sensors are meant to withstand hot temps. With a bad o2, the computer should notice working outside its range. Should trigger check engine light, and run in safe mode/by pass the o2. Any check engine light? Have you plug in obd2 reader see if any code pops? Might be something other than O2.

Only got one code and it said high intake air temp. It’s weird because the car wasn’t doing this before the install. It drove perfect. It’s just kind of stumping me.

Also checked the MAF and put a volt meter to it and it had all the correct numbers.

Okay so we got the dump and new o2 sensor in and the car runs great and is not acting funny anymore. But now when I lift off throttle the a/f dips to 12-11 instead of leaning out? Any ideas?

Forgot to post an update, the culprit was a bad front o2 sensor and my bov was very soft. Tightened it up and the car is running strong again!