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
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.
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.
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.
Sir Hugh of Bognor
The difference between men and boys is the price of their toys.
There's so much useful information on the internet.
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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