530i Oxygen sensor issue

[Larryat42]

I have a 2001 530i (M54) with 120K miles. Car has the expected Oxygen sensor issue. I ordered the Bentley Manual, all 4 sensors and the low cost tool suggested from Bavarian Autosport . They said it would be easy... Actually the two pre-converter sensors look straight forward. The post-convert sensors apparently will be easy to replace, once I get the motor out of the car....



Have I screwed up here? While I have replaced the Disks and Pads on my 530 and my wife’s 323 without issues, (I though it was a nice Christmas present, but she did not seem very impressed...) pulling a motor is not something I could even consider. I can not even see the post converter sensors using a mirror. Could it be that I should approach them from under the car? Should I give up, return the parts and go to the better equipped BMW mechanic or even, gasp, the dealer (my credit is good so I will be able to re-mortgage the house). Or maybe I could just replace the pre-converter because they are the ones the cause the problems because they deal with slightly higher temperatures...



It is my intention to get about 200K miles on this car. Your assistance is greatly appreciated.

[Erwin8r]

I would replace the pre-converter sensors and re-boot the DME--this may cure your problem....

[632 Regal]

you will probably have to replace them from under the car, pissibly drop the exhaust to do so...I'm just guessing tho.

[Larryat42]

I would replace the pre-converter sensors and re-boot the DME--this may cure your problem....
Thanks for your suggestion. I assume the DME is the Service Engine Soon light (MIL). While that light has been going on, my analysis was based more on the consistent warnings that the Oxygen sensors would need to be replaced at 100K miles and the seat of the pants knowledge that something is dramatically wrong. It is like the primary jets were plugged on a carburetor fueled motor, although it still idles well. I do like the basic logic of fix the easy parts now, but as I plan to add many more miles, I would like to solve the issue in one effort. Thank you again for your suggestion.

[Larryat42]

you will probably have to replace them from under the car, pissibly drop the exhaust to do so...I'm just guessing tho.
I knew that I needed to buy some more equipment...;)