Hi all,
A bit of background first ... I replaced my MAF sensors about 2 weeks ago, and was flowing over the magic 140 l/hour, with a 'top score' of 159 in 2nd gear.
However ever since I have felt power dropping ever so slightly. I re-ran the same test and achieved 122. Same stretch of road, temperature and gear, so I emailed board member DavidS who suspected my Pre-Cat O2 sensors were not sending the right information to the DME, and that they could probably do with replacing given that they have never been done.
So I rang BMW who did not have any in stock, however suggested NGK/NTK as they make a direct OEM replacement. The part number is OZA447-E27 and I purchased mine for AUD$125 (USD$94) each.
Installation requires the following tools
- 10mm socket + wrench
- Hammer
- adjustable Shifter (I did not have any open ended spanners handy).
1) Jack up car safely. The higher you jack it the easier it will be to get the required leverage on the sensor.
2) You will see that the sensor is attached to its socket under a plastic cover. make sure you know which sensor you wish to replace, I.E the one before the cat convertors (closest to engine)
3) Undo the two 10mm nuts with the wrench. Be careful not to strip them as they are a weak plastic.
3) Remove the connector from its housing and un-plug the O2 sensor.
4) With the spanner attach it to the o2 sensor. A few taps with the hammer and it should loosen.
5) unscrew and remove the sensor.
Installation is a reverse of the above. A few notes however
1) Be careful with the sensor.. it houses some metals that dont take too kindly to being dropped.
2) Before installation remove the plastic cover (pictured) on the NTK sensor. This is to protect the anti-seize paste.
2) the NGK/NTK ones come with the appropriate anti seize paste already on the thread so any more is not necessary.
Fuel flow is increasing and should return to normal after the ECU 'learns' the new (and correct) figures being fed to it by the new MAFS and O2 sensors.
I have attached some photos that may be of interest. Notice the difference between the old and new ones. It looks like one bank was running lean and the other rich. Most bizzare. I hope DavidS contributes to this thread.
Cheers,
Aaron
A bit of background first ... I replaced my MAF sensors about 2 weeks ago, and was flowing over the magic 140 l/hour, with a 'top score' of 159 in 2nd gear.
However ever since I have felt power dropping ever so slightly. I re-ran the same test and achieved 122. Same stretch of road, temperature and gear, so I emailed board member DavidS who suspected my Pre-Cat O2 sensors were not sending the right information to the DME, and that they could probably do with replacing given that they have never been done.
So I rang BMW who did not have any in stock, however suggested NGK/NTK as they make a direct OEM replacement. The part number is OZA447-E27 and I purchased mine for AUD$125 (USD$94) each.
Installation requires the following tools
- 10mm socket + wrench
- Hammer
- adjustable Shifter (I did not have any open ended spanners handy).
1) Jack up car safely. The higher you jack it the easier it will be to get the required leverage on the sensor.
2) You will see that the sensor is attached to its socket under a plastic cover. make sure you know which sensor you wish to replace, I.E the one before the cat convertors (closest to engine)
3) Undo the two 10mm nuts with the wrench. Be careful not to strip them as they are a weak plastic.
3) Remove the connector from its housing and un-plug the O2 sensor.
4) With the spanner attach it to the o2 sensor. A few taps with the hammer and it should loosen.
5) unscrew and remove the sensor.
Installation is a reverse of the above. A few notes however
1) Be careful with the sensor.. it houses some metals that dont take too kindly to being dropped.
2) Before installation remove the plastic cover (pictured) on the NTK sensor. This is to protect the anti-seize paste.
2) the NGK/NTK ones come with the appropriate anti seize paste already on the thread so any more is not necessary.
Fuel flow is increasing and should return to normal after the ECU 'learns' the new (and correct) figures being fed to it by the new MAFS and O2 sensors.
I have attached some photos that may be of interest. Notice the difference between the old and new ones. It looks like one bank was running lean and the other rich. Most bizzare. I hope DavidS contributes to this thread.
Cheers,
Aaron
