O2 sensor

upstate NY · Post by **upstate NY** » 19 Jan 2011, 20:54

So the symptoms I have been having with my 95 850. More than your average white exhaust, fuel smell upon engine start, 14.5 mpg, sluggish acceleration. OBDII gave me P0133 which I found to be the upstream or front O2 sensor. Does anyone else have or had these symptoms with the same code? If so was it the sensor and upon replacement did it solve the problems. I sure hope that 110.00 part will solve these issues. Thanks for any input!

Post by **Ozark Lee** » 20 Jan 2011, 05:44

My son's car used to throw the P0133 all the time but after I fixed his exhaust the code went away. Most O2 sensor codes are not actually the sensor itself, they arise from either vacuum leaks or exhaust leaks.

...Lee

upstate NY · Post by **upstate NY** » 20 Jan 2011, 10:26

What about all the symptoms I have described above?

Post by **jblackburn** » 20 Jan 2011, 10:32

I never got a code, but my gas mileage went into a steady decline - I was getting like 12 mpg/18 hwy. V8's get better gas mileage than that! After exhausting all other possibilities - vacuum leaks, new spark plugs, checking over and over again for exhaust leaks, I decided to spring for a new front O2 sensor. Problem solved - my gas mileage shot up into mid-20's again.

lhailah · Post by **lhailah** » 20 Jan 2011, 15:58

Hi I am in upstate NY as well. I have a 98 xc70 awd, currently fwd ): . I had my catalytic converter replaced about 3000 miles ago, aftermarket. sounds pretty cheap compared to the oem part that was originally on the car. it corroded off ( bought the car in long island about 7000 miles ago)
anyhow i checked the codes for the first time a few days ago. I got P0141 P0136 and p0140. I get a stong fuel smell when starting the vehicle from the outside and inside.
I think its more important i do the pcv system first as i'm getting some oil pooling around the spark plugs and a slow leak when the engine runs for over 25 minutes at idle(just something i noticed when jacking the car up for the last oil change) coming from the subframe near the passanger front wheel. I plan to order the 02sensor as soon as i determine if bank 1 sensor 2 refers to the front or rear.
Upstate, how many miles are on your car?

Post by **Ozark Lee** » 20 Jan 2011, 16:09

I plan to order the 02sensor as soon as i determine if bank 1 sensor 2 refers to the front or rear.

Bank 1 - Sensor 2 is the rear sensor.

...Lee

lhailah · Post by **lhailah** » 20 Jan 2011, 16:53

thanks!
So i wonder would this bad sensor/harness be the cause of fuel odor upon starting or the clogged pcv system?
hopefully i'll get to do the pcv this weekend and see the results..

Post by **jblackburn** » 20 Jan 2011, 18:13

The rear sensor does nothing to control the fuel/air mixture - it simply monitors whether or not the catalytic converter is functioning properly. Do you have any other codes, EVAP system perhaps?

Post by **Ozark Lee** » 20 Jan 2011, 18:27

To Ihaila - My gut says that it is unrelated. The smell of fuel on startup says a bad fuel pressure regulator, perhaps a flooded EVAP cannister or a leaky injector. White smoke at startup is pretty normal until the car reaches operating temperature. Beyond that things get a bit deeper in the woods.

As Justin said, the Bank 1 Sensor 2 is usually a catalytic converter issue unless the code says Open or Shorted. The car always starts in an open loop mode that ignores the O2 sensors for its decisions.

...Lee

upstate NY · Post by **upstate NY** » 20 Jan 2011, 18:49

The code that I got was P0133 O2 sensor circuit, slow response, (Bank 1, Sensor 1) Which I believe to be the front. I have the same problem with oil pooling up around the spark plug wires as well since I just changed the wires, plugs, cap and rotor. I am sure the PCV is right in the near future. I will go ahead with the front O2 sensor change out. Hopefully that will do the trick. Thanks for all the feed back! Miles reading is 171,456