E46 Lambda / O2 sensors

[ChrisBrand]

Quick question: I take it lambda/oxygen/O2 sensors are all the same thing? After installing my new MAF sensor the car felt very under powered. Got a error msg for oxygen sensor bank 1 and bank 2. I take it these are both pre cat sensors?

Thanks for the help!

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[Philip Foglar]

As far as I know, these are the same, but in some cases they are fitted pre and post cats.

Was hoping that the new MAF would have solved your car's problem! I wonder if the O2 sensors are somehow slightly fowled from incorrect fuel mixture, and if they would self-clean now that the MAF has been replaced.

I also would like to know more about this, but I gather that the MAF tells the ECU how much air is coming into the intake so that the ECU can make fuel/air mixture adjustments, the O2 sensors are there to "report" back as to the combustion process to the ECU which can then make more changes. So from my understanding, it's a relationship between the MAF and O2 sensors that control the fuel mixture etc.

But I am really hoping some more clued up members will add to this and correct where I am possibly wrong! :thumbs:

 

[ChrisBrand]

Correct Phillip. There is that relationship aspect. After replacing the maf but not the crank sensor, the car really struggled with in gear acceleration, or rather when you flat the pedal at around 3000rpm. So not sure if the new maf sensor is reading the source of the problem differently. I guess the best option is to put the faulty maf back and see what errors I get then.

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[Philip Foglar]

I tested something out with my car this morning, thanks to Rory!!

He came over with his E87 130i which has the same N52B30 motor, and therefore the same MAF sensor (even the airbox is the same), so tested the MAF sensor from his car on mine - simply swapped the air box over.

To help the matter, I cleared throttle adaptations again and off we went for a drive.

While the pinging was definitely less, it was still there, so not sure what else to try, or if it would need more time to settle than just the half an hour or so that we tested this. But, the car drove a helluva lot better than it does with the original MAF sensor! Smoother, does not struggle or feel like it's being held back, and not jerky like it is normally. Basically like driving a different car!

So I reckon a new costly MAF is in order - was just really hoping that this would have cured the pinging issue too!

 

[Peter@AEW]

Diesel Electric for MAF

 

[Philip Foglar]

Diesel Electric for MAF

Thanks! Will give them a try!! :thumbs:

 

[sclass]

How did you clear your throttle adaptations? Why is it nacessary to do so, is it for autos to learn driving style or can this be applied to manuals? Sorry for the 20 questions

 

[ChrisBrand]

So doing a bit of research I discovered the following. It seems that the car is equiped with Oxygen/02 sensors.

When you fit an aftermarket management system (I have a UniQ) it may be necessary to fit Lambda sensors which measure the flow of air and adapt fuel mixture via the management system for better performance.

This is how I understand it unless someone with better knowledge can educate me further?

Also another stupid question: Does the M52TU28 have pre-cat oxygen sensors? I tried looking for it quickly yesterday, without removing the engine cover, but couldn't see it?

 

[Philip Foglar]

With the UniQ it does make matters a bit more complicated, so not really sure.

How did you clear your throttle adaptations? Why is it nacessary to do so, is it for autos to learn driving style or can this be applied to manuals? Sorry for the 20 questions

This works on manual and automatic models as far as I know, but basically, you insert the key fob and turn the ignition on. Then press and hold the throttle all the way down for 30 seconds. After this, release the pedal and turn the ignition off and leave for 2 minutes. All done! At least that's what I remember - I did post this somewhere on the forum...

Problem is, it just relearns almost immediately, so you are back to square one. But cannot hurt to do this every so many months or so.