I'm missing my rear O2 sensor. The one by the cat. I'm sure you guys know that though. Anyway, is this a really bad thing? Midas put on an exhaust for me, welded it to the cat, and there is a wire hanging there.. with no O2 sensor. It's been like this since June. I had a mechanic look at it yesterday and noticed it was not there.
I'm pissed at Midas, yet worried about my car now. I had to have Nissan clean my fuel injectors a couple weeks ago.

 

Does your car idle/run ok? with no o2 sensor it would definately run funny. wait... so midas actually welded on your exhaust to the cat?

 

The car is running rich. That's the only actually problem I've been having with it. Other than having the check engine light stay on 24/7. If there are other problems, I haven't found them yet.

The mechanic actually showed me that the O2 sensor was missing.

And yeah, Midas did weld my exhaust onto my cat. They're ****ing stupid.

 

take it back to midas and have them fix the problem... they could actually loose their business license for altering the factory emissions systems... take your paperwork from the original repair and tell the manager they you need your o2 sensor reinstalled into the exhaust system that they "forgot"to replace when they did the exhaust work... if they give you any flack over it ask for the corp headquarters toll free number so you can speak to the district manager and see if he can resolve the problem...

replacing the rear o2 sensor should have the cel taken care of after you reset your ecu...

if they say anything about the length of time... play the stupid part... i did not know it was missing... i dont know anything about cars yadda yadda yadda... and i wanted my car checked out because of the cel being on since the exhaust work was done...

as far as midas welding onto the cat... welding a cat in is a standard procudure... as most of their cats do not come with header flanges... i used to work for them and this was how it was done... this is for 2 reasons... one you cant remove the cat and 2 it is easier to make changes to the exhaust when needed for fitment issues...

have em correct the problem as they should do...

 

you really should have made him replace it... but he never told you that

 

Yes I know.. but why make him fix something that he didn't do. I'd rather take time and money out of Midas and make them do it all for free. They were the douches who messed it up to begin with.

I've never had a problem like this before. I'm just angry. I don't know if they did this in hopes I would return with a "problem" and they would charge me an arm & a leg to get it fixed or what.

 

Update.

I took the car to Midas today and my O2 sensor IS there. Thank god. That was a big relief. They showed me that it was old and rusty though.. so I definately need a new one.

They also showed me my evap canister and said that one of the hoses might be bad and that's why that code is being thrown out.

Question though, is the evap canister located under the rear of the car on the passenger side? He showed me something there. I also have the vent control valve code being thrown out too.. and that is under the hood correct?

So many codes and I'm trying to locate all of them and make sure I don't get one messed up with the other!

 

Give me the actual codes you're getting - and I hope you're getting those codes from the ECU self-diagnostic LED, right?

 

You might be throwing a code 32 if the vacuum line to the EGR is fried. I just fixed mine the other day. The EGR hose that runs from the header to the EGR can get hot and melt the rubber vacuum hose.
Run a ecu diagnostic and if it reads code 32 I can get you the easy step by step. Actron code scanners for convenience are like $170, or you can get the actron code scanner book for $30. JCwhittney online sells these, a must have if you are fixing your own equipment.

 

I am not running my second 02 sensor for about 1 1/2 month and nothing is wrong with the car. The only reason this o2 sensor is there is to verify that the "pre-cat" is doing is job. It does not calculate anything about air/fuel. I replaced the downpipe(frontpipe) where the "pre-cat" is and I am waiting to have a adapter for my 02 sensor since the diameter is not the same.

 

That is FALSE.....
Read your FSM a little bit better. The KA runs rich without the second o2 sensor, it is part of the smog emissions systems and does effect ignition timing and air to fuel.