[Sanjayo1]

Hi


I have an embarrassing problem and cannot get the MAF sensor off to clean.
I have an F36 4 Series thats done 34k and doubtful the MAF has ever been cleaned.

I try and move the 'white clip' fully up (not shown on the pictures) and then tried to disconnect it, to no avail.

Is there a specific way to remove? I dont want to put too much pressure and end up snapping something or worse.

Tried looking at YouTube, but non are shown with my style of connector.
Please help - pictures attached.

[Billfitz]

I can't tell from your pictures exactly what they're showing, but my MAF doesn't look anything like that. Whatever that is that it's attached to doesn't like like the intake either. A picture from further away would help.

[Jvac]

Not specific to the maf, but with any electrical sensor on these cars. You just have to be very careful and patient. Make sure the retention tab is depressed (wedge a small screwdriver or something in there to hold it down). Also, make sure there isn't another retention clip on the flip side that would need to be depressed as well. Gently but firmly (I know, how can it be both) push, pull, and wiggle. Walk away for a minute and come back if you have to, because if you fight it too hard you could rip the wires out or crack the housing on the connector. Either of those will have you buying new parts. I went through this with the maf on one of our cars- it developed some kind of bond between the mating surfaces that was beyond reasonable for such flimsy little parts. Eventually it let go but I thought for sure it was going to break first.

[Sanjayo1]

Originally Posted by Billfitz

I can't tell from your pictures exactly what they're showing, but my MAF doesn't look anything like that. Whatever that is that it's attached to doesn't like like the intake either. A picture from further away would help.

Thanks - Additional pictures attached

[Sanjayo1]

Originally Posted by Jvac

Not specific to the maf, but with any electrical sensor on these cars. You just have to be very careful and patient. Make sure the retention tab is depressed (wedge a small screwdriver or something in there to hold it down). Also, make sure there isn't another retention clip on the flip side that would need to be depressed as well. Gently but firmly (I know, how can it be both) push, pull, and wiggle. Walk away for a minute and come back if you have to, because if you fight it too hard you could rip the wires out or crack the housing on the connector. Either of those will have you buying new parts. I went through this with the maf on one of our cars- it developed some kind of bond between the mating surfaces that was beyond reasonable for such flimsy little parts. Eventually it let go but I thought for sure it was going to break first.

The white clip moves back, as per my red arrow in one of the pictures, however, the main unit wont budge. Checked underneath the clip and it doesnt seem that theres anything holding it. Really strange, it wont come off. Really embarrassing Lol

If any one has any experience on these clips, any advice would be welcomed!

[Jvac]

That's definitely the maf, but it looks a little different than mine. There's some trick to that mechanism to get it to release, you're just missing it. But, I would ask why you want to clean it. I thought mine was causing a problem around 35k miles. Took it apart and it was pristine. Cleaned it twice anyway, didn't fix the problem. Unless you run an intake with no filter, it's probably not dirty yet. That's not really the point, but maybe save yourself some aggravation for a bit. Another trick is, once the clip is depressed, use another tool like a flat screwdriver or trim tool to leverage/pry the harness away from the sensor while you are pulling, but again, be careful not to be too forceful. The plastic will crack easily under force if the retention clip isn't released.

[Orion4]

Have you tried depressing the white rectangle while sliding back the rest of the white clip? That looks like a retention clip.

[Billfitz]

It's different than on my N20. In any event you don't have to release the clip. Remove the two torx head screws and the entire shebang will slide out of the intake. You may need to get one of these to get at them:

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

This is an incredibly good tool to have on hand. You won't use it often, but will be glad to have it when nothing else will work.

[Sanjayo1]

Thanks for all of the suggestions and advice!

Jvac - Had the car for around 9 months now. When I got it, the air filter was filthy, clogged and the oil needed changing. I replaced all filters and did an oil change. Always wanted to get round to the MAF to clean as the advice is to clean every so often once in a while to keep it running optimum.

Orion4 - Yes tried that and it wouldn't move.
Billfitz - Purchased a similar tool already - thanks for the suggestion of removing everything.

In the end I did 2 things.

1) Drove the car for a while (1 hour) for everything to warm up.
2) I was standing from the side of the car trying to push it up previously. This time, I changed my angle, and stood infront of the car bonnet and pushed up with more force trying to not break anything.

The Good

I think with point 1 helped by warming up the plastic. I have finally managed to get the connector off!

Then cleaned the MAF with MAF cleaner and it seemed to be idling slightly lesser than previously (marginally) but I think it has had some impact. I need to drive it properly to properly confirm.


The bad

There is a very small plastic 'notch' on the actual MAF sensor that has broken. I suspect it broke when I was previously trying to pull it off and it was jammed (see pictures).

As a result, the 'white latch' doesn't lock anymore as there's no notch to latch onto.

There is enough of the connector there on the MAF sensor and it seems a pretty tight fit so hopefully wont come off. I might run it and see how it goes for a while - as I don't want to replace the whole MAF sensor for tiny plastic 'notch', but that notch is crucial in securing the plastic white fixing. (Please see pictures). A genuine BMW part will be anything from 180 USD onwards.

Worst case scenario, if the MAF sensor comes off the car won't get damaged should it? Air will still go in, just that the ECU may not perform at its optimum right?

Alternatively, I was thinking of ordering ordering a plastic connector or cheap connector with a 'notch' similar to mine, cutting off the plastic connector and then Gorilla gluing it to my MAF sensor.

I would try and replace the plastic housing on the MAF sensor with another (non working MAF) donor one from ebay, but they appear to be a sealed unit and I'm doubtful I would be able to exchange the plastic parts alone.

The other idea I had would be to wrap some electrical tape around the sensor head, then put the connector on - which should secure it further.

I would welcome any ideas / suggestions

[Billfitz]

The sensor can't come off, it's held in place by those torx head screws. I'd do the tape.

[Sanjayo1]

Originally Posted by Billfitz

The sensor can't come off, it's held in place by those torx head screws. I'd do the tape.

Thanks Bill - I meant the Sensor connector....

[Jvac]

Good deal. I'd secure it with some tape or a dab of high temp caulk-type sealant, spanning over the joint between the sensor and the harness (on the outside once the parts are reassembled, of course) just to keep some surface resistance on it so they don't rattle apart. It's easily cut free with a utility knife if you ever need to remove the sensor.

[Sanjayo1]

Originally Posted by Jvac

Good deal. I'd secure it with some tape or a dab of high temp caulk-type sealant, spanning over the joint between the sensor and the harness (on the outside once the parts are reassembled, of course) just to keep some surface resistance on it so they don't rattle apart. It's easily cut free with a utility knife if you ever need to remove the sensor.

Thanks Jvac - I put electrical tape around the sensor head (where the connector plugs in), which made the connection really tight after attaching the connector. Then I taped up the outside of it. Should be good now.

I'll keep an eye out for a cheap new MAF sensor on ebay, but a brand new costs 180USD upwards, I can't justify the cost when the sensor is working brilliantly, so electrical tape will do. I don't think the sensor connection will come off now, its on pretty tight.

On another note, the idle speed has dropped 2-3 digits after cleaning the MAF. Would certainly recommend cleaning the MAF if not done so, but obviously taking the MAF out in one piece of course