XSeries-forum

Hi guys,

Having problem with my 2006 BMW X3 2.0D (82K miles). The car hesitates and lack power around 2000rpm.

Took to local BMW specialist who said car threw fault code 003FFO (MAF sensor), caused engine management light to come on. After further diagnostics he said it seems it was a faulty MAP (manifold absolute pressure sensor) sensor as the pressure being read by it was not what it should be. Changed MAP but still no power, in fact the car performed was worse than before! Lumpy idle and wouldn't rev past 1500- 2000 rpm. He then said it is most likely carbon build up as these cars suffer from build up badly and inlet ports get restricted. He suggested taking apart inlet manifold and head and cleaning manually as solution, but thats a a days worth of work. Said he's had a few X3's with same issue before. However when the MAF sensor is disconnected the car runs 100% full of power and runs smooth as it should.

I decided to have the engine hydrogen carbon cleaned today, some power has been restored but still a hesitation.

I'm now left thinking could this be a MAF issue after all, the car had a genuine Bosch MAF sensor fitted. If the engine was blocked with carbon would it run mint with the MAF disconnected? Don't want to spend £300 on new genuine Bosch  MAF sensor to find its not the problem.

Your help is much needed! All thoughts would be appreciated. Thanks

When I collected mine 2 years ago it felt like your description.
The dealer fitted a new MAF and all was good.

Hi jagr,

Did you try cleaning your MAF sensor before changing? thinking of trying that first.

Also if the engine was coked up with carbon, would the car run mint with MAF disconnected?

No.  The fuel injection system needs the MAF.

[quote="X5Sport"]
No.  The fuel injection system needs the MAF.
[/quote]



So does the fact that the car runs mint with the MAF disconnected suggest I have a faulty MAF and that the fault is not being caused by carbon build up?

Thanks.

You need a MAF to get the mixture right so if it is giving false data you'll get an issue.  Without the MAF you will just get a default setting in the ECU which won't cope with everything under the full power range driving needs.  It could be too rich (smoke) or too lean (will overheat).

If you clean it, use carb cleaner and be VERY gentle.

I understand what your saying about the car using a default setting when the MAF is disconnected.

What I would like to know is that since the car runs well when the MAF is disconnected (using the fail safe settings provided by ECU)  but is almost un drivable with it connected, does this mean that carbon build up in the engine is not the problem?

I would say the MAF is the problem.

http://www.ebay.co.uk/itm/Bosch-MAF-Mas ... Sw3ydVsgtr

This from another arm of Eurocarparts. And it's only £44 delivered

Thanks for the link, although I don't think the linked item is compatible with my car. Looks like they are for the petrol engines?


I think this is the one I Need (also from car parts 4 less)

http://www.carparts4less.co.uk/search/4 ... 1&1&000009


I just don't wanna shell out £140 to find the MAF isn't the issue and the engine does in fact need de coking!

Has a fault code read been done since the change?  If not it would be a good idea and might point at the MAF.  It needs to be done on the proper BMW system, or on an Autologic system (Bosch Autocentres often have them).

Not heard of anyone needing a decoking on this forum whereas MAF sensors are frequent sources of trouble.  Cleaning them can make the issue worse as they are very sensitive devices.

I read loads of posts on BMWland ( when it was still on line ) about coked up X3 2.0 d engines. It's the same engine as most other 2.0d Beemers but they reckon the mapping used for the X3 causes it to coke up. Turbos are notorious for going on the X3' as well, oil starvation.
As said by others, the MAF defaults to a standard setting when disconnected . And aftermarket MAFs have been known to be very troublesome too. I would fit a genuine one myself after reading many posts of dicky aftermarket ones.

[quote="X5Sport"]
Has a fault code read been done since the change?  If not it would be a good idea and might point at the MAF.  It needs to be done on the proper BMW system, or on an Autologic system (Bosch Autocentres often have them).

Not heard of anyone needing a decoking on this forum whereas MAF sensors are frequent sources of trouble.  Cleaning them can make the issue worse as they are very sensitive devices.
[/quote]

By change do you mean has the MAF been replaced? If so the MAF has not been replaced yet. The code was read by my local indie BMW specialist and he tried recoding the MAF and reseting the adaptations. Same fault code returned.

The MAF I linked to in above post is genuine BOSCH part. But I just want to be certain that the MAF is to blame before replacing it and find that its the engine being bungged up. Its just strange how it runs like new with it disconnected.

[quote="rali"]
Hi jagr,

Did you try cleaning your MAF sensor before changing? thinking of trying that first.

Also if the engine was coked up with carbon, would the car run mint with MAF disconnected?
[/quote]

This happened the day I collected my car so did not have chance to experiment. The dealer hooked it up to their Autologic and it said faulty MAF so they got a new one from BMW.

They did have to code it in on the Autologic after fitment.

[quote="rali"]
What I would like to know is that since the car runs well when the MAF is disconnected (using the fail safe settings provided by ECU)  but is almost un drivable with it connected, does this mean that carbon build up in the engine is not the problem?
[/quote]

In my service history BMW claimed my car needed a Decoke but was never done. It also had a new turbo the year before I bought it.
I bought it with 40k miles.

Change the MAF and enjoy.

My car has also had a new turbo fitted a few months ago by previous owner. I do hope its a case of just replacing the MAF and not a decoke