I believe my 2001 530d has a dead MAF I am loathed to pay IRO £175-£250 for a genuine Bosch replacement unless I have to I mean it is not like the Bosch ones are dead reliable is it!! (My VW diesel ate through 2 of them). I was wondering if anyone has tried some of the many clones available on eBay which seem to originate from China (and I'd bet that's where the Bosch ones are made too) Any personal experience shared would be appreciated Thanks David
A friend of mine bought one for his Alfa and it resulted in eratic behaviour, it would be gutless for a few seconds, then would be OK, then a repeat when he changed engine condition. He said his mpg suffered too. He sent it back to the seller on EBay that sent it back and said there was nothing wrong with it. In the end, he bought a second hand genuine unit which restored the car's characteristics.
Hmm. Just beats me how they can ever sell these things if they are so crap. Hopefully, I'll get some more opinions.
I recently had a suspect intermittent MAF/AFM problem on an old 325iX and at the suggestion of someone on a 325iX mailing list, I unsealed the AFM, cleaned the rheostat tracks with a pencil eraser and ran some
400 grit under the contactor arm. I also put a drop of oil on the vane hinge. Before you do that, you might want to identify the two connector pins for the airflow and take a multimeter to them and check that the resistance changes as you move the vane, and that the vane is not binding. Mine was roughly in the range of 2K to 4K ohms, but YMMV. I think that the only two reasons for an AFM to fail are 1) bad rheostat, and 2) a binding vane. I'm sure that someone else will come up with other reasons, but these are the most common ones.
Sounds about right!
Sadly, this is not an air flap type, it is the heated wire type rheostats went with first generation injection systems. This is whhat is in mine:
Well, I guess I'll just go and put my old fart cap on then. Good luck!
Old classic more like ;-)
Usually the hot-wire type fail or perform badly due to crap on the wire. There are cleaners on the market that will clean the MAF and the inlet to get back lost performance but obviously not if the wire is broken.
On VAG cars they don't seem to be that good. Bosch prices aren't so bad now anyway- mine for my Audi was about 80 quid. Personally I'd just bite the bullet and buy the Bosch unit.
There's so much useful information on the internet.
NOT!
The reason the hot wire MAF's go out of calibration is that after many "burn off cycles" (where a higher current is passed through the wire to burn the deposits you mention off) the wire actually changes diameter and then has a permanent error in the reading. The only fix for this is to install a new platinum wire, and that's what is done when a MAF is rebuilt.
Now back to the MAF's from China: they are not good for your car. Why do you think they had boats called Chinese JUNKS??
Hmm - looked at that and the Bosch is over £200 for my Bimma. Bloody rip-off when you consider how unreliable they are. I just bought an equivalent made by pierburg (reassuring German manufacture) It is just the insert as opposed to the ducting too (which was in fact easier to replace once I bought security torx bits to remove it). Performs like new - no problems
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