1995 BMW M3 air cleaner

BOSCH
DME
MM
AND
M33
.1

COMPONENT
TESTS
AND
REPAIRS

Consult
Table
a
for
engine
application
information
for
the

Bosch
DME
3
.1
and
3
.3.1
systems
.

The
DME
3
.1
and
DME
3
.3
.1
systems
are
similar
in
opera-

tion,
with
knock
control
and
VANOS
operation
being
the
key

differences
.
DME
3
.1
engines
arenot
equipped
with
VANOS

or
knock
detectors,
while
the
DM
E3
.3
.1
system
is
.

CA
UTION-

Use
onty
a
digital
multimeter
when
testing
wiring
.
Use
of
an
analog
VOM
may
damage
the
engine
control
module
.

Fig
.
25
.
Mass
air
flow
sensor
.
Hot
wire
sensor
usedon
carswith
DME
Electrical
tests
of
the
main
and
fuel
pump
relays
and
the



3
.1
(1992
6-cylinder
models)
.

DME
engine
control
module
(ECM)
are
covered
earlier
in
this

section
.
Fuel
pump
tests
are
covered
in
160
Fuel
Tank
and



CAUTION-
Fuel
Pump
.
Use
only
a
digital
multimeter
when
checking
the
mass
air
flow
sensor
.
An
analog
meter
can
dam-
Mass
Air
Flow
Sensor



age
theair
flow
sensor
.

There
are
two
types
of
mass
air
flow
sensors
used
onthe



1
.
Disconnect
air
flow
sensor
from
air
cleaner
only
.
Leave

cars
covered
by
this
section
.
Testing
procedures
vary
de-



it
connected
to
duct
leading
to
intake
manifold
and

pending
on
type
installed
.
The
airflow
sensor
is
not
adjustable



leave
wiring
harness
connected
.

and
must
only
be
tested
with
a
digital
multimeter
.

Mass
Air
FlowSensor
Variants

"
1992
M50
engine

DME
M3
.1
.
.
.
.
...
..
mass
air
flow
sensor-hot
wire

"
1993-1995
M50
and
S50US

DMEM33
.1)
.
...
...
.
mass
air
flow
sensor-hot
film

Mass
air
flow
sensor
(hot
wire),

testing
and
replacing

When
the
engine
is
running,
a
current
is
used
to
heat
a
thin

wire
in
the
center
of
the
sensor
.
See
Fig
.
25
.
The
current
in
the

wire
is
regulated
to
maintain
a
temperature
of
100°C
more

than
the
air
passing
over
it
.
The
current
used
to
heat
the
wire

is
electronically
conneced
into
a
voltage
measurement
corre-

sponding
to
the
mass
of
intake
a¡
r
.

To
keep
the
wire
clean,
it
is
heated
to
a
temperature
of
about

1,000°C
(1,830°F)
for
one
second
.
This
"burn-off"
cycle
takes

place
automatically,
four
seconds
after
the
engine
is
tumed
off
.

lf
thehot
wire
breaks
or
if
there
is
no
output
from
the
air
flow

sensor,
the
ECM
automatically
switches
to
a
"limp-home"

mode
and
tucos
on
the
Check
Engine
light
.
The
engine
can

usually
be
started
and
driven
.
The
air
flow
sensor
has
no
inter-

nal
moving
parts
and
cannot
be
serviced
.

FUEL
INJECTION



130-
1
7

2
.
Start
engine
and
run
it
to
normal
operating
temperature
.

3
.
Rev
engine
toat
least
2,500
rpm,then
shut
it
off
.
Look

through
meter
at
hot
wire
.
After
approximately
four
sec-

onds
wire
should
glow
brightly
for
about
one
second
.

NOTE
-

If
the
wire
glowsas
specified,
then
the
airflow
meter
and
ECM
are
probably
operating
correctly
.
lf
the
wire
does
not
glow,
continue
testing
.

4
.
lf
the
wire
does
not
glow,
remove
air
flow
sensor
and

look
through
it
to
see
if
wire
is
broken
.
lf
wire
is
broken,

meter
will
have
to
be
replaced
.

5
.
Reinstall
air
flow
sensor
and
harness
connector
.
Peel

back
rubber
bootfrom
harness
connector
.
Working

from
rear
of
connector,
connect
digital
voltmeter
across

terminals
1
and
4
.
See
Fig
.
26
.

6
.
Start
and
rev
engine
toat
least
2,500
rpm,thenshut
it

off
.
After
about
4
seconds,
voltage
should
riseto
about

4
volts
for
about
one
second
.
lf
voltage
is
present,
but

wire
does
not
glow,
air
flow
sensor
is
faulty
and
should

be
replaced
.

7
.
lf
voltage
is
not
present
in
step
6,
turn
ignition
key
on

and
check
for
voltage
and
ground
at
sensor
.
There

should
beground
at
pin
4
.
There
should
be
positive
(+)

battery
voltage
at
pin
2
.

BOSCH
DME
M3
.1
AND
M32
.1
COMPONENT
TESTS
AND
REPAIRS

Brake
rotor,
removing
and
installing

Brake
rotors
shouldalways
be
replaced
in
pairs
.

Fig
.
9
.



Brake
rotor
mounting
screw
(arrow)
.

3
.
Inspect
rotor
for
excessive
grooving,
cracks,
and
warp-

ing
.
Check
rotor
thickness
.
See
Table
b
.

4
.
Installation
is
reverse
of
removal
.

"
Clean
rotor
with
brakecleaner
before
installing
.

"
If
brake
fluid
hose
veas
removed
or
loosened,
brake

systemmustbe
bled
as
described
aboveunder

Bleeding
Brakes
.

BRAKES
340-
7

5
.
Once
brake
assembly
is
instalind,
depress
brakepedal

several
times
to
adjust
caliper
and
pads
.

"
Pedal
should
feel
firm
and
be
at
proper
height
.

"
Check
fluid
leve¡
.
Top
up
if
necessary
.

NOTE-

M3
models
use
directional
brake
rotors
and
mustbe
in-



NOTE-

stalled
on
the
proper
side
.
Part
numbes
are
cast
finto



When
installing
new
rear
brake
rotors,
the
parking

therotors
.
A
part
that
ends
in
an
odd
number
is
a
left



brakeshouldbe
adjusted
.
See
Parking
Brake
.

rotor
.
One
that
ends
in
an
even
number
is
a
right
rotor
.

1.
Remove
caliper
as
described-above
and
hang
from



Tightening
Torques
chassis
using
stiff
wire
.



"
Brake
rotor
to
wheel
hub
..........
16
Nm
(12
ft-Ib)

"
Front
brake
caliper
to
steering
arm
...
110
Nm
(81
ft-Ib)

NOTE-



"
Rear
brake
caliper
to
traíling
arm
....
67
Nm
(50
ft-Ib)

Do
notloosen
caliper
brake
hose
.



"
Road
wheel
to
hub



...
..
.
100
±
10
Nm
(74
t
7
ft-Ib)

2
.
Remove
mountingscrew
holding
rotor
to
wheel
hub
.



,

See
Fig
.
9
.



Table
b
.
Brake
Rotor
Reconditioning
Specificati*M`

Front
Rear

Vented
rotor
wear
limit
(min
.
thickness)



20
.4
mm
(0
.803
in.)

Solid
rotor
wear
limit
(min
.
thickness)



8
.4
mm
(0.331
in
.)

M3
models
wear
limit
(min
.
thickness)



26
.4mm
(0
.977
in
.)



18
.4
mm
(0
.723
in
.)

Axial
runout
(max
.)
rotor
removed



0
.05
mm
(0
.002
in
.)



0
.05
mm
(0
.002
in
.)
rotor
installed



0
.20
mm
(0
.008
in
.)



0
.20
mm
(0
.008
in
.)

CAUTION-

M3
brake
rotors
must
not
be
machined
.

MASTER
CYLINDER

The
brake
master
cylinder
is
mounted
to
the
front
of
the
vac-

uum
booster
on
the
driver
side
bulkhead
.

Master
cylinder,
removing
and
installing

1
.
Using
a
clean
syringe,
empty
brake
fluid
reservoir
.

WARNING
-

Brake
fluid
is
highly
corrosive
and
dangerous
to
the

environment
.
Dispose
of
it
properly
.

NOTE-

On
original
equipment
rotors,
the
mínimum
allowable



2
.
Disconnect
brake
fluid
leve¡
sender
connector
from
fluid

thickness
is
stamped
on
the
rotor
hub
.
Measure
the
rotor



reservoi
r
cap
.

brakingsurface
with
a
micrometer
at
eight
to
ten
different

points
and
use
the
smallest
measurement
recorded
.



3
.
Disconnect
brake
fluid
lines
frommaster
cylinder
.
See

Fig
.
10
.
Disconnect
hydraulic
clutch
system
supply
line
.

4
.
Unscrew
mounting
nuts
and
remove
master
cylinder

from
brake
booster
.

5
.
Make
sure
all
nuts,
fluid
couplings,
thread
bores,
and

mating
surfaces
are
clean
.

MASTER
CYLINDER

611
Wipers
and
Washers

GENERAL
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.....
.
......
.
611-1



Windshield
wiper
motor,

removing
and
installing
.
...............
.611-8

WIPER
BLADES
.
.
.
.....
.
.
.
.
.
.
...
....
.611-1

Wiper
Blade
Cleaning
Problems
.
.
.
.
.
.
.....
611-1

Wiper
blades,replacing
...
.
.
.
.
.
.
.
.
.
.....
611-1

Wiper
blade
inserts,
replacing
.
.
.
.
.
.
.
.
.....
611-2

Wiper
arms,
removing
and
installing
.
.
.
.....
611-2

WINDSHIELD
WIPER
ASSEMBLY
.
.
.....
611-3

Windshield
wiper
assembly,
removing

and
installing
(4-door
models)
.
.
.
.
.
.
.....
611-3

Windshield
wiper
assembly,
removing

and
installing
(2-door
models)
.
.
.
.
.
.
.....
611-5

GENERAL

This
repair
group
covers
windshield
wiper
and
washer
sys-

tem
repair
information
.
Please
note
that
some
procedures
are

different
for
2-
and
4-door
models
.

The
windshield
wiper/washer
stalk
switch
assembly
is
cov-

ered
in
612
Switches
and
Electrical
Accessories
.
Electrical



NOTE-
wiring
diagrams
and
relays
for
the
wiper/washer
system
are



BMwhas
available
a
special
toollgauge
(BMWspecial
covered
in
Electrical
Wiring
Diagrams
.



tool
no
.
00
9210)
to
align
the
angle
of
the
wiper
arm
to
the
windshield
glass
.

WIPERBLADES

CA
UTION-

Never
turn
on
the
wiper
blades
while
the
hood
is
open
.
Damage
to
the
wiper
system
and
hood
may
occur
.
Toensure
safetyduring
wiper
biade
system
procedures,
remove
the
windshieldwiper
fuse
.
See
610
Electrical
Component
Locations
.

Wiper
Blade
Cleaning
Problems

Common
cleaning
problems
with
thewipers
includestreak-

ing
or
sheeting,
waterdrops
after
wiping,
and
blade
chatter
.

Streaking
is
usually
caused
when
wiper
blades
are
coated

with
road
film
or
car
wash
wax
.
Clean
the
blades
using
soapy

water
.
If
cleaning
does
not
cure
the
problem,
the
blades
should
be
replaced
.
BMW
recommends
replacing
the
wiper

blades
twice
a
year,
before
and
after
the
cold
season
.

WIPERS
AND
WASHERS



611-1

WINDSHIELD
CLEANING
SYSTEM
......
611-9

Windshield
spray
nozzle,

removing
and
installing
.......
.
........
.611-9

Washer
fluid
reservoir,
replacing
.........
.611-9

Windshield
washer
fluid
pump,
replacing
..
.
......
.
........
.611-9

Washer
fluid
level
sensor,
replacing

(models
with
check
control)
.
.
.
.
........
611-10

Wiper
blade
chatter
may
be
caused
by
dirty
or
worn
blades,

or
by
wiper
arms
that
areout
of
alignment
.
Clean
the
blades
and
windshield
as
described
above
.
Adjust
the
wiper
arm
so

that
there
is
even
pressure
along
the
blade,
and
so
that
the

blade
at
rest
is
perpendicular
to
the
windshield
.
If
problems

persist,
theblades
and
wiper
arms
should
be
replaced
.

The
wiper
blades
can
be
renewed
in
one
of
two
ways
:
either

by
replacing
the
complete
blade
or
by
replacing
just
therubber

insert
.

Insert
replacement
is
the
mosteconomicalmethod,
al-

though
overtime
the
wiperblade
itselfwill
become
worn
.
One

ruleof
thumb
wouldbe
to
replace
just
the
inserts
every
second

time
.

Wiper
blades,
replacing

1
.
Pivot
wiper
arm
off
windshield
.

2
.
Position
wiperblade
approximately
perpendicular
to

wiper
arm
.

3
.
Remove
wiperblade
from
wiper
arm
by
depressing
re-

taining
tab
and
sliding
blade
out
of
arm
.
See
Fig
.
1
.

Drops
that
remain
behind
after
wiping
are
usually
caused
by



NOTE-

oil,
road
film,
or
diesel
exhaust
residue
onthe
glass
.
Use
an



Some
wiperblade
versions
may
havetwo
retaining

alcohol
or
ammonia
solution
or
a
non-abrasive
cleaner
(such



tabs
.

a
s
Bon-Ami



to
clean
the
windshield
.

GENERAL

4

Foglight
assembly,

removing
and
installing

1
.
Foglight
lens
release
catch
2
.
Foglight
lensrear
protective
cap
3
.
Foglight
bulb
4
.
Foglight
lens

Fig
.
7
.



Foglight
assembly
(removed)
.

0012682

Fig
.
6
.



Measure
gap
B
(1.5
mm)
between
front
of
hood
and
headlight
cover
.
Note
horizontal
headlightadjusting
nut
(1)
and
retaining
screw
(2)
.

The
following
procedure
covers
foglight
lens
and
foglight

buib
replacement
.
Foglight
components
are
shown
in
Fig
.
7
.

0012683

EXTERIOR
LIGHTING



630-
3

1
.
Insert
a
screwdriver
in
upper
air
duct
inlet
of
front
lower
valence
and
disengage
foglight
lens
catch
mechanism
.
Swing
light
outward
and
gently
disengage
hinged
end
.
See
Fig
.
8
.

Fig
.
8
.



Insert
screwdriver
in
upper
air
duct
inlet
.
uu¡¿biu

2
.
Remove
rear
protection
capand
disengage
steel
wire
foglight
bulb
clamp
.

3
.
Remove
bulb
from
rear
of
foglight
assembly
.
Discon-
nect
electrical
harness
from
foglight
bulb
.

CAUTION
-

Do
not
touch
halogen
bulbs
with
yourbare
hands
.
If
necessary
wipe
buib
using
a
clean
cloth
damp-ened
withrubbing
alcohol
.

4
.
Installation
is
reverse
of
removal
.
Check
electrical
con-nector
for
corrosion
.
Spray
with
contact
cleaner,
if
nec-
essary
.

Bulb
Application
(USA
Models)
:

"
Foglight
bulb



......
...
..
...
..........
Hl
(55w)

FRONT
LIGHTING