540i 95 O2 sensor? tune up?

[dblogo]

I need to replace the front O2 sensor in my car. How many are there. Is there 2 before the cat or 1? AND were would be the best place to get everything for a tune up? Does a e34 95 540i have 2 oil filters or am i just seeing something wrong?

[pgrindstaff]

Both O2 sensors are in the front of the catalytic converters. There is only one oil filter in the 540, but there are two fuel filters, which is what I think you are thinking of. As for a place to get all of these parts I would suggest BMA parts or BavAuto. There are many other places to use but I have had good experiences with both of these.

[Jehu]

What makes you think you need to replace O2 sensors? I haven't done mine in the almost 90,000 miles that I've owned it and have no idea if or when they were ever replaced before i bought it two years ago. I still get about a mixed average of around 17 mpg city/hgy and find no hesitation or lack of power. Should I expect to see much of an improvement in performance if i were to have them replaced when its up on the lift getting the rear sub-frame mounts replaced?

[632 Regal]

replace ALL intake and front/rear plate gaskets first.

[dblogo]

replace ALL intake and front/rear plate gaskets first.
I took it to a shop and had a diagnostic ran, and it came up that one is not responding and the other is iffy. something is affecting the way that my car idles. the idle is really low and it does not drive well in auto/drive. i have been driving in manual and it seems fine. the car has 177k miles on it so i dont know what all has been done to it and when it last had a tune up. it is guzzling the gas pretty fast also. any sugestions?

[BMW4LIFE]

I took it to a shop and had a diagnostic ran, and it came up that one is not responding and the other is iffy. something is affecting the way that my car idles. the idle is really low and it does not drive well in auto/drive. i have been driving in manual and it seems fine. the car has 177k miles on it so i dont know what all has been done to it and when it last had a tune up. it is guzzling the gas pretty fast also. any sugestions?


iffy is the mechanic term for....please listen to me and change this part cause my wife needs a new purse!

a red flag always raises when a mechanic uses terminology like that!

my 2 cents

[dh305]

I need to replace the front O2 sensor in my car. How many are there. Is there 2 before the cat or 1? AND were would be the best place to get everything for a tune up? Does a e34 95 540i have 2 oil filters or am i just seeing something wrong?

You are supposed to replace at 60k. There is a warning light that will come on and the engine will start to idle with more hesitation/rough idle. If you have a code reader (purchase at Bavarian) it will read your codes and tell you if it is the sensor. It will tell you which one! You should replace both. I replaced both at 90k. Didn't have any problems until then. Now runs much better.