got an x3 at work coming up airflow fault code tested it on scope etc think its slightly out.

got a new one no different same sort of readings/graph as the old one, it seems it controls the throttle valves on the inlet.if you unplug them so they are always open its fine revs and drives sweet, or if you unplug the air flow they open up faster than they do with it plugged in which makes it drive fine.

doesnt sound like theres an air leak cant see any only low milage 57k

any ideas

thanks

 

what engine? 2.5?

have you checked the manifold for cracks?

 

sorry 2.0l diesel, well thing is if you unplug air flow the valves open soon as rpm is increased?

 

Did you replace the meter with a bmw part ? I did a 3 series bm last week with the same problem and it turned out that the aftermarket airflow meter would not work propper so got a bm meter and all is fine

 

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ive done a lot of readin gon the net and it seems this is also the most likely as its amotor factor one, going to get onto bmw monday to see if they are different part numbers etc to the one we have

 

Its deffo the meter mate as the aftermarket one gives a false reading so dont waist time messing around with it and get a propper bm part and i am 100% sure it will fix it. I waisted 4 hrs doing the same checks just to find it was the meter. BMW,VW,VAUXHALL must have dealer meters as the aftermarket units dont work and your only waisting your cash

 

i seem to remember i had trouble with a 320d maf and it needed to go to bmw to be reconfigured or somthing silly?

 

ben might be worth rebumping this during the weekday if you can so Carlo can answer as he works for Bmw I think and seems to know a bit

 

thanks for everyones inputs here id like to think that its afm will bump again monday for carlo

 

bump for carlo to see hopefully

 

Hi mate only just seen this if it revs ok with the meter unplugged then 9 times out of 10 its the airflow meter motor factor ones are usually ok but you only get what you pay for if its a really cheap nasty one might be worth trying a better quality part..

Bmw's are a nightmare trying to get a fault code for air flow meter on the petrol cars its usually a air leak with hoses on the inlet split / breather pipes but on the diesels its not so common.

I would try a genuine air flow meter its a expensive test tho we have been bitten so many times with air flow faults.

At that mileage they are bad for not boosting getting to turbo mileage but that wouldnt stop it reving in neuteral would only notice that on the road under load.

 

cheers carlo its a bosch one so not too nasty, its also a diesel too but i have heard from a few people that some air flows on these have to be re coded or similar??

 

You need to reset the adaptations as when it fails the car keeps trying to recalculate its valuations to bring it into spec but even without them reset you should see a difference when you plug the new one in. i would get them to send you another bosh one a fitted part claim i have seen garages returning the old one in the new box as they dont really show any sign of age then we spend ages to find this out.