Mass air flow sensor

[320iNE]

Hello guys. My 320i M20 has had an unstable idle for quite a while and a mechanic I know who is ex-BMW (80's 90's era) has said that the mass air flow sensor needs changing.

eBay is a bit of a minefield for me in terms of being sure what I need to buy (the mechanic wants me to source the part).

Can anyone point me in the right direction in terms of the PN# that I need and where the best place may be to obtain one? Would prefer to avoid main dealer if possible, bit skint at the moment.

Many thanks in advance,

[BenHar]

Go to this site: https://www.realoem.com/bmw/enUS/select ... &archive=1

Insert your VIN. Find the part and number.

Ben

[arrisbmw]

the mass air flow sensor is not used on idle.
idle is controlled by the icv and a by pass rubber tube.

[arrisbmw]

if fact your car has not got a m.a.f on it at all , its a air flow meter. afm if we are talking E30

check it on here wiki

AFM
After being filtered, the amount of air is measured by the Air Flow Meter. This simple sensor involves a door that opens wider as more air flows. As the door opens, it moves an arm across a resistor surface (called a carbon track), which sends a variable voltage to the ECU. The main body of the AFM is bolted to a bracket mounted to the inner wing.

The Air Flow Meter is specific to each E30 engine if you are looking to source a replacement, but they very rarely fail. If you think your AFM is going bad, you can pry open the plastic lid of the sensor box, and very gently adjust the metal arm so that it connects to a fresh area of the carbon track.

your idle problem is probably caused by the I,CV BEING DIRTY or a vaccun leak some where hard to find.

[Brianmoooore]

if fact your car has not got a m.a.f on it at all , its a air flow meter. afm if we are talking E30

check it on here wiki

AFM
After being filtered, the amount of air is measured by the Air Flow Meter. This simple sensor involves a door that opens wider as more air flows. As the door opens, it moves an arm across a resistor surface (called a carbon track), which sends a variable voltage to the ECU. The main body of the AFM is bolted to a bracket mounted to the inner wing.

The Air Flow Meter is specific to each E30 engine if you are looking to source a replacement, but they very rarely fail. If you think your AFM is going bad, you can pry open the plastic lid of the sensor box, and very gently adjust the metal arm so that it connects to a fresh area of the carbon track.

your idle problem is probably caused by the I,CV BEING DIRTY or a vaccun leak some where hard to find.

This is all correct (in fact, I think it was lifted from a post I made years ago), BUT if the AFM is giving an implausible output, because of being faulty, it can upset things. Unplugging the AFM should have no effect at idle (although you will be unplugging the inlet air temp. sensor as well, so there will be a small difference).
The last line of the quote is most likely the root of your problems.
What year is your 320i?

[arrisbmw]

no it wasn,t lifted from something you wrote, things I,ve learned over the last few years
(many of which have come from your vast experience of the E30 posted here, all spot on I may add ) but the middle bit was copied from wiki.

[Stephenmoooore]

It's the wiki bit I mean.