My car is eating oxygen sensors!!

[epj3]

I replaced my sensor a month and a half ago with a bosch 13725 oxygen sensor and rewired it to my connector.

After I got my exhaust back on the car, I reinstalled the sensor (The shield was clean on the tip) and it worked fine for a few miles then the check engine light came on and it was the O2 sensor again. It was absolutely covered in carbon. I replaced it - with the same thing as before. It worked fine until today, when the check engine light came on again and it is the oxygen sensor. I havent taken it out yet (as I just got home... would be a little hot) but I'm willing to bet it's covered in carbon again.

My question is.. what the hell?? I never have any smoke come out the tail pipe, and the car was running okay up until today. I've been getting 21 mpg city (Actual mpg.. not going by the OBC) and the car always starts and idles normal (a little rough but normal for as long as I've owned it).

I cant keep tossing down $50 for an oxygen sensor. Should I cut a check and have someone look over the entire EFI system?

 

[lpquick]

I replaced my sensor a month and a half ago with a bosch 13725 oxygen sensor and rewired it to my connector.

After I got my exhaust back on the car, I reinstalled the sensor (The shield was clean on the tip) and it worked fine for a few miles then the check engine light came on and it was the O2 sensor again. It was absolutely covered in carbon. I replaced it - with the same thing as before. It worked fine until today, when the check engine light came on again and it is the oxygen sensor. I havent taken it out yet (as I just got home... would be a little hot) but I'm willing to bet it's covered in carbon again.

My question is.. what the hell?? I never have any smoke come out the tail pipe, and the car was running okay up until today. I've been getting 21 mpg city (Actual mpg.. not going by the OBC) and the car always starts and idles normal (a little rough but normal for as long as I've owned it).

I cant keep tossing down $50 for an oxygen sensor. Should I cut a check and have someone look over the entire EFI system?

When was the last time you changed your oil? Does your car use any oil between changes?
The carbon buildup at an alarming rate is an indicator that something is going wrong and needs to be looked at. So many possibilities, we need more information about the car before any one can offer an educated guess.

 

[epj3]

New BMW's burn a little oil -- older bmw's are known to burn oil. I go through about a quart every 2,000 - 3,000 miles which is quite low for E30's.

The car is a 1988 325is with 174,000 miles and usually runs better than my parents 4 year old pontiacs. I checked for intake leaks via brake and parts cleaner and there was no influx in RPM's. I thought it was the gas so I put in Chevron 89 octane gas which is what I use every now and then, and it always helps. I change my oil every 3,000 miles. I did just get done replacing a bunch of stuff on the car -- had the entire exhasut off from the manifold down (Manifold was off of the engine and downpipe was disconnected from the manifold -- I replaced all gaskets which were purchased from bavauto and I torqued on everything properly. The car passed state emissions testing on saturday a few hours after I replaced the sensor. There WAS a lot of smoke immediately after I replaced the exhasut -- which I would understand why that sensor went bad. Now, there is NO smoke in the upper RPM's like before but there is the usual hesitation and stuttering in relationship to the bad sensor.

I'm thinking my entier EFI system needs to be given a tune up. My idle valve isnt working properly but it hasnt worked for about 2 years, and the sensor in it when I purchased the car lasted that entire time.

 

[Ghost]

Biased voltage or blown plug? Did you get it dirty, drop it or hit it against anything? I’ve heard they should be handled with more delicacy than a spark plug and any type of damage or obstruction to the opening can cause premature failure from faulty readings.

 

[epj3]

Biased voltage or blown plug? Did you get it dirty, drop it or hit it against anything? I’ve heard they should be handled with more delicacy than a spark plug and any type of damage or obstruction to the opening can cause premature failure from faulty readings.

It went right from the packaging to the car w/out removing the plastic cover.

 

[epj3]

I took the sensor out, cleaned it with some sea foam (engine treatment) and then blew it out with compressed air, and now it works fine.

 

[Ghost]

Glad you got it fixed!

 

[MrElussive]

Ya know they say if you disconnect your O2 sensor altogether, you gain another 10hp because your car thinks it's cold outside and provides maximum combustian efficiency or something crazy like that.
I did that to my Jetta for like 5 minutes. It makes the car idle higher and act more "nervous". Even that piece of shit Jetta didn't deserve to have a disabled O2 sensor, whether it gave me more power or not.