mass air flow meter !?

Dazz wrote: sorry for the late reply lads i do know where the MAF is but i think i will give it a skip .i have been lookin through some other forums and came across a couple of posts where it caused more trouble than anything else so i dont know... Davec did you find any differance in the performance ??

I didn't notice any Difference, but I think I will be changing it in the next month or so.   I've read on other forums that the Pierburg MAF is Very good.  I just had a quick look on ebay - didn't see any.  but they do show up from time to time.

Let us know if you do change it / and what diference it makes

Verry right Kin that is what is the case. There are treads on other sites who clearly show this there is even a table with comparisons which ones to take as replacements. Saves a bummer

The bmw service and repair states clearly that after the change of any parts like MAF's Cam and Crank sensors or the O2 ones the DME has to be reset and the car has to run on newer cars it takes up to 30min. driving to get everything working there are always some who think they know better....... well weleave it with that.

We fixed quiet some cars with a reflashing of the software and an enthusiastic spin afterwards to set the values and presto another happy carowner.    

We never used pierburg or any other aftermarket stuff

MAF's are electronic devices which change an electronic value depending on the amount of air which flows by and cools the "hotfilm" part (sorry for my english) this varying value together with the temp data from the air plenum and the engine temp are used for basic fuelling tables used by the DME.

I don't design car engine management but from looking at different ones it's obvios that as different engines use different amounts of air different MAF's are used for example my e34 530v8 uses a different one as the 540 e34. They both run when swapped around however I guess that the fuelling will be out and the mixture will be too rich or too lean as "BMWCARE" mentioned the too lean setting would have quiet damaging consequences for the engine a too rich one for the wallet at the pumps.

Most MAF's on german cars are build by BOSCH and I can not see while you couldn't cross use say VAG ones given that the values they return to the DME are the same or within verry narrow margins of it.

However for anyone working on customer cars this is a tricky decision to make due to liability issues, but we did use them on our own cars and my brother still uses them in Munich (of all places) on his 2 cars with no problems. They have verry stringend emission laws over there which are tested EVERY year so a too rich car would fail;. My brother drives like a nutter and due to unrestricted sections of motorway and him Vmaxing his car quiet regular I'm pretty sure he would have killed the engine if it would run to lean. (burned out valves etc). There are tons of post on other bmw related boards about this issue and even magazines mention it sometimes.

My guess is that it could easily be veryfied if they run ok if you use an exhaust probe to measure the fuelling after install.

BMWCARE quote:

"BMW do state that the DDE is reset - but this is not just the clearing of fault codes. This does not reset adaptations.
When you "reflash the software" - are you resetting the adaptations?

On an E39 530d, Bosch (who are the OE suppliers) clearly state that "if 0 928 400 527 is installed as replacement for 0 928 400 314 the control unit MUST be reprogrammed". This is the same as what BMW say... Except BMW use their own part numbers ;) "

Thats exactly what I said.

Fault codes have no input on the set values which are unique to each engine due to different wear etc. In the old days a value reset was achived by disconnecting the battery for 30+minutes and a drive. Autologic and Carsoft have that feature built into them so it's easy to do. On diesel engines however it saeems that they nearly always need a reprogramming (Flashing) as there are numerous revisions released from BMW and most bad running cures only if the whole thing gets redone.

 I go and fetch breaky now