If you are unsure of what an
air mass meter (air flow meter) is or where to locate it then
we suggest that you read our other
article what
is an air mass meter.
The full version of this
article complete with photos is available to view at ;
www.carbasics.co.uk/how_to_change_air_mass_meter.htm
What can go
wrong with the air mass meter ?
Well, if you imagine that
everytime your car is driven the vane or electrical wire inside is having air
passed over it.
Although this air has been filtered via the panel filter within
the airbox, there will still be minute particles of dust and pollen etc.
that
will build up over time and reduce the air mass meters efficiency.
Eventually it
will stop working and this usually results in a significant affect on your cars
power and its fuel economy.
It is not a part that will last forever, and although there are people that
state that you can clean the internal parts,
it is probably better in the long
run if you just get it changed when it finally does stop working.
There was an
intermittent fault on my VW Sharan (turbo diesel) whereby on occasion after a
long run or having a lot of people in it,
the power would disappear and the
turbo was virtually non-responsive. After a while or if I switched the ignition
off,
the problem would go away but it kept doing this for about 6 months. I had
a search around on the internet and looked in
many online forums and found that
the most likely cause was the air mass meter was on its way out.
I had the
option of giving a clean to see if this would get rid of the problem, but
because of the miles this car has done
I decided that this would be a waste of
time and would get round to replacing it at some point or to get
it changed when
it finally gave up for good (whichever situation would come first).
With my VW
Sharan when the air mass meter did not give any signal out to the ECU,
the car
would switch itself into 'limp mode'. This 'limp mode' was the cause of
the lose of power and it was the
ECU (cars computer) running in a mode that
would minimise any damage to the engine.
For the purpose of
this step-by-step article, the information below will be related to changing the
air flow (air mass)
meter on a VW Sharan 1.9tdi 1997. The procedure for most
other cars will be very similar and just as simple.
What do I
need ?
Don't worry, you should not need any expert
mechanical tools costing a small fortune.
For chaning the VW Sharan air mass meter all we need was an 8mm allen key and a
pair of pliers,
ooh and about 15-30 minutes of spare time.
How long did
it take ?
From start to finish the job took about 15
minutes.
Here are the steps for changing
your air mass meter ;
On the VW Sharan, the air
mass meter is situated on the left of the engine bay behind the airbox.
It is
bolted onto the airbox at one end with 2 x 8mm allen bolts and clamped at the
other end onto a plastic air pipe with a clamping ring.
1.
Unplug the wiring from the meter by squeezing the clips wings inwards and
pulling up. Do not pull it by the wires.
2.
We will start off by removing the
plastic pipe at the back of the air mass meter.
When you push the the 2 clamping ring wings towards each other, the diameter of
the clamp increases allowing
you to push the pipe off the end of the meter. With
your right hand take your pliers and put them over clamping ring wings,
push the pliers together and as the ring opens, separate the pipe from the meter
with your left hand.
You can leave the clamping ring in place around the loosened pipe.
3.
The next thing to do is to unclip
the top off the airbox and turn it over.
This will be easy now you have removed that plastic pipe, and noe of the other
pipes on the airbox will need to be removed.
Turning over the airbox lid at this
point will make it easier to remove the 2 x 8mm allen bolts holding the meter.
There are 2
clips holding the airbox lid in place, one at the front and one at the back.
Locate one of the clips, put your hand down there and feel the bottom of the
clip.
If you pull the bottom of the clip upwards, it will release the top of the
clip. Push the top of the released clip
away from the airbox lid and repeat with
the other clip.
4.
Now you should have easier access to both of the bolts holding the air mass
meter.
Undo the 2 x
8mm allen bolts using your 8mm allen key. Once removed make sure you put them in
a safe place.
The meter should now separate from the airbox, make sure that you
retrieve the large 'o' ring
from the outside of that end and fit it to the new
air mass meter.
5.
Fitting the new air mass meter is a direct reversal of what you have just done ;
a.
fit the old 'o' ring onto the new air mass meter
b.
bolt the meter back onto the lid of the airbox
c.
clip the airbox lid back on to the
airbox, making sure that the
panel filter is seated correctly
d.
Connect the plastic pipe back onto
the other end of the air mass meter,
making sure that the clamping ring is
securely in place
e.
reconnect the wiring plug onto the top of the meter
FINISHED.
It has been
suggested that the battery power should be disconnected for at least 30 minutes
so that the ECU (cars computer) will reset.
This will ensure that all the old
ECU settings are wiped and it will then start up again using the new air mass
meter readings.
This could be done at the start and remain disconnected during the new install
to save time,
or it could be disconnected for 30 minutes after you have
finished.
Where did you
get your air mass meter from ?
Ours was purchased from
'German Swedish and French' car parts. They had the item we needed on the shelf
so I drove round to fetch it.
This was a Pierburg air mass meter, a brand new
original part - identical to the one we took off. The cost was about £75.
We were informed that if it had been a bosch item, then there would have been a
£25 surcharge on top that would be
refunded until we bought the old faulty one
back. The reason for this is that the Bosch items are reconditioned,
the
internal parts are changed for new ones and these are fitted into the
reconditioned bodies.
Whichever
your version is, they are readily available from local motor-factors as well as
from online retailers.
In fact with the online retailers you can usually get
them cheaper than what we paid for ours.
But we needed ours quickly and could
not wait the few days for it to be delivered.
Please note that there are cheaper MAF sensors available but these will most likely be pattern copies and not the
original
Bosch or Pierburg versions.
You will have to do your own research (online)
as to how reliable the copies are
compared to the Bosch or Pierburg items.
For the full
version of this article complete with photos, please visit ;
Tags: waste of time, efficiency, photos, online forums, fuel economy, fir, cars, pollen, minute particles, vane