Tires,
checking
inflation
pressure
Brake
pad/rotor
wear,
checking
Correct
tire
pressuresare
important
to
handling
and
stability,
Al¡
E36
cars
are
fitted
withdisc
brakes
at
al¡
four
wheels
.
See
fuel
economy,
and
tire
wear
.
Tire
pressures
change
with
temper-
Fig
.
24
.
Although
thebrakesare
equipped
with
a
brake
pad
ature
.
Pressures
should
be
checked
often
during
seasonal
tem-
warning
system,
the
system
only
monitors
one
wheel
per
axle
.
perature
changes
.
Correct
inflation
pressures
canbe
found
on
It
is
recommended
that
pad
thickness
should
be
checked
the
driver's
door
pillar
and
in
the
owner's
manual
.
Note
that
tire
whenever
the
wheels
are
off
or
brakework
is
beggg
done
.
pressuresshould
be
higher
when
thecar
is
more
heavily
loaded
.
WARNING
-
Do
not
inflate
any
tire
to
a
higher
pressure
than
the
tiress
maximum
ínflation
pressure
listed
on
the
side-
wall
.
Use
cara
when
addlng
air
to
warm
tires
.
Warm
tire
pressures
can
increase
as
much
as4
psi
(0.3
bar)
over
their
cold
pressures
.
Tires,
rotating
BMW
does
not
recommend
tire
rotation
.
Due
to
the
cars
sus-
pension
design,
the
fronttires
begin
to
wear
first
at
the
outer
shoulder
and
the
rear
tires
begin
to
wear
first
at
themiddle
of
the
tread
or
inner
shoulder
.
Rotating
the
tires
may
adversely
af-
fect
roadhandling
and
tire
grip
.
NOTE-
The
main
purpose
of
tire
rotation
isto
promote
even
wear
and
maximum
tire
life
.
Tire
life
may
be
decreased
slightly
if
the
tires
are
not
rotated
.
Wheels,
aligning
Routine
maintenance
of
the
brake
system
includes
maintain-
ing
the
brake
fluid
in
the
reservoir,
checking
brakepads
for
wear,
checking
hand
brake
functíon,
and
inspecting
the
system
for
fluid
leaks
or
other
damage
.
Check
that
brake
hoses
are
correctly
routed
to
avoidchafing
or
kinkíng
.
Inspect
unions
and
brake
calipers
for
signs
of
fluid
leaks
.
Inspect
rigid
fines
for
corrosion,
dents,
or
other
damage
.
Inspect
flexible
hoses
for
cracking
.
Replace
faulty
hoses
or
lines
as
described
in
340Brakes
.
WARNING
-
Incorrect
installation
or
overtightening
hoses,
fines,
and
unions
may
cause
chafing
or
leakage
.
This
can
lead
to
partíal
or
completebrake
system
failure
.
MAINTENANCE
PROGRAM
020-
1
7
B323
Fig
.
24
.
Disc
brake
pad
wear
can
checked
through
opening
in
caliper
.
The
brake
caliper
should
be
unbolted
from
the
suspension
strut
to
properly
inspect
the
brake
pads
and
the
rotors
.
See
Fig
.
25
.
Brake
caliper
removal
and
installation
procedures
are
given
in
340
Brakes
.
BMW
recommends
checking
the
front
and
rear
alignment
once
a
year
and
whenever
new
tires
are
installed
.
See320
Steering
and
Wheel
Alignment
for
a
more
detailed
discus-
sion
of
alignment
requirements
and
specifications
.
Brake
Pad
Lining
Minimum
Thickness
(Dimension
A)
Brake
system,
inspecting
"
Front
and
reardisc
brake
pads
....
3
.0
mm
(0
.12
in)
Brake
fluid,
replacing
BMW
strictly
recommends
replacing
the
brake
fluid
every
two
years
.
This
will
help
protect
against
corrosion
and
the
ef-
fects
of
moisture
in
the
(luid
.
See340
Brakes
for
brake
fluid
flushing
procedures
.
Parking
brake,
checking
The
parking
brakesystem
is
independent
of
the
main
braking
system
and
may
requireperiodic
adjustment
dependingon
use
.
Adjust
the
parking
brake
if
the
brake
lever
can
be
pulled
up
more
than
8
clicks
.
Check
that
the
cable
moves
freely
.
A
de-
scription
of
the
parking
brake
and
parking
brake
adjustment
can
be
found
in
340Brakes
.
UNDER-CARMAINTENANCE
020-
1
8
MAINTENANCE
PROGRAM
Fig
.
25
.
Inspect
brake
pads
with
the
caliper
removed
.
Minimum
brake
pad
thickness
shown
by
dimension
(A)
.
NOTE-
The
parking
brake
may
lose
some
of
its
effectiveness
if
it
is
not
used
frequently
.
This
is
due
to
corrosion
build-
up
on
the
parking
brake
drum
.
To
remove
corrosion,
ap-
plythe
parking
brake
just
until
it
begins
togrip,
then
pulí
the
lever
up
one
more
stop
(click)
.
Drive
thecar
approx-
imately
400
meters
(1,300
ft
.)
and
release
the
brake
.
To
recheck
the
adjustment
of
the
parking
brake
see340
Brakes
.
UNDER-CAR
MAINTENANCE
0011920
Manual
transmission
fluid,
checking
and
filling
The
manual
transmission
fluid
leve¡
should
be
checked
at
specified
intervals
.
Check
and
fill
the
transmission
with
the
car
ona
leve¡
surface
.
Transmission
(luid
leve¡
checking
and
re-
placement
procedures
are
covered
in
230
Manual
Transmis-
sion
.
Automatic
Transmission
Service
The
automatic
transmission
is
not
equipped
with
a
dipstíck
.
Therefore,
checking
the
ATF
level
is
an
ínvolved
procedure,
which
includes
measuring
and
maintaining
a
specified
ATF
temperature
during
the
checking
procedure
.
For
more
complete
ATF
service,
including
checking
ATF
lev-
e¡
and
ATF
filter
replacement
procedures,
see
240
Automatic
Transmission
.
Front
suspension
and
steering
linkages,
inspecting
Inspection
of
the
front
suspension'and
steering
includes
a
check
of
all
moving
parts
for
wear
and
excessive
play
.
Also
in-
spect
the
rubber
seals
and
boots
for
cracks
or
tears
that
could
allow
the
entry
of
dirt,
water,
and
other
contaminants
.
See
310
Front
Suspension
.
Exhaust
system,
inspecting
Rear
suspension,
inspecting
Exhaust
system
life
varies
widely
according
to
driving
habits
Final
drive
and
rear
drive
axle
service
consists
of
checking
and
environmental
conditions
.
If
short-distance
driving
pre-
and
changing
the
gear
oil,
inspecting
for
leaks,
and
checking
dominates,
the
moisture
and
condensation
in
the
system
will
the
rear
drive
axle
rubber
boots
for
damage
.
not
fully
dryout
.
This
will
lead
to
early
corrosion
damage
and
more
frequent
replacement
.
The
areas
where
leaks
are
most
likely
to
occur
are
around
the
driveshaft
and
drive
axle
mounting
flanges
.
For
more
infor
Scheduled
maintenance
of
the
exhaust
system
is
limitedlo
mation
on
ídentifying
oil
leaks
and
their
causes,
see330
Rear
inspection
.
Check
for
restrictions
due
to
dents
or
kinks
.
Check
Suspension
.
for
weakness
or
perforation
due
to
rust
.
Check
lo
see
that
all
the
hangers
are
in
place
and
properly
supporting
the
system
and
that
the
system
does
not
strike
the
body
.
Alignment
of
the
sys-
Final
drive
oil
leve¡,
checking
temand
the
location
of
the
hangers
aredescribed
in
180
Ex-
haust
System
.
Check
the
lubricant
leve¡
with
thecar
level
.
Remove
the
oil
filler
plug
.
The
leve¡
is
correct
when
the
fluidjust
reaches
the
edge
of
the
filler
hole
.
Install
and
tighten
the
oil
filler
plug
when
Manual
Transmission
Service
the
oil
level
is
correct
.
See
Fig
.
26
.
Manual
transmissionservice
consists
of
inspectingfor
leaks
The
final
drive
should
be
filled
with
a
special
BMW
lubricant
and
checking
and
changing
the
fluid
.
available
through
an
authorized
BMW
dealer
.
In
addition,
the
lubricant
type
varies
depending
onwhether
or
nota
limited-slip
Evidence
of
transmissionleaks
is
fkely
to
beseenaround
the
differential
is
fitted
.
driveshaft
mounting
flange
and
at
the
bottom
of
the
bellhousing
.
For
more
information
on
identifying
oil
leaks
and
their
causes,
see230ManualTransmissionand210
Clutch
.
Tightening
Torque
"
Finaldrive
filler
plug
to
final
drive
housing
..................
70
Nm
(52
ft-Ib)
020-20
MAINTENANCE
PROGRAM
Seat
Belts
Washing
Chassis
Dirt
and
other
abrasive
particles
will
damage
seat
belt
web-
Periodic
washing
of
the
underside
of
the
car,
especially
in
bing
.
If¡t
is
necessary
to
clean
seat
belts,
use
a
mild
soap
solu-
winter,
will
help
prevent
accumulation
of
road
salt
and
rust
.
The
tion
.
Bleach
and
other
strong
cleaning
agents
may
weaken
the
besttime
to
wash
the
underside
is
just
after
the
car
has
been
belt
webbing
and
should
be
avoided
.
driven
in
wet
conditions
.
Spray
the
chassis
with
a
powerful
jet
of
water
.
Commercial
or
self-service
car
washes
may
not
be
best
WARNING-
for
this,
as
they
may
recycle
the
salt-contaminated
water
.
Do
not
clean
the
seat
belt
webbing
using
dry
clean-
ing
or
other
chemicals
.
Allow
wet
belts
to
dry
before
allowing
them
to
retract
.
Speeial
Cleaning
The
condition
of
the
belt
webbing
and
the
function
of
the
re-
tractor
mechanisms
should
be
inspected
.
See720
Seat
Belts
for
seat
belt
inspection
information
.
Exterior
Washing
The
longer
dirt
isleft
on
the
paint,
the
greater
the
risk
of
dam-
aging
the
glossy
finish,
either
by
scratching
or
by
the
chemical
effect
dirt
particles
may
have
on
the
paintedsurface
.
Do
not
wash
the
car
in
direct
sunlight
.
If
the
engine
hood
is
warm,
allow
it
to
cool
.
Beads
of
water
not
only
leavespots
when
dried
rapidly
by
the
sun
or
heat
from
the
engine,
but
also
can
act
as
small
magnifyingglasses
and
burn
spots
into
the
finish
.
Wash
thecar
with
a
mixture
of
lukewarmwater
and
a
car
wash
product
.
Rinse
using
plenty
of
clear
water
.
Wipe
the
body
dry
witha
soft
cloth
towel
or
chamois
to
prevent
water-spotting
.
Waxing
For
a
long-lasting,protective,
and
glossy
finish,
apply
a
hard
wax
after
thecar
has
been
washed
and
dried
.
Use
carnauba
or
synthetic
based
products
.
Waxing
is
not
needed
after
every
washing
.
You
can
tell
when
waxing
is
required
by
looking
at
the
finísh
when
it
is
wet
.
If
the
water
coats
the
paint
in
smooth
sheets
instead
of
forming
beads
that
rol¡
off,
a
new
coat
of
wax
is
needed
.
Wax
shouldnot
be
applied
to
black
trim
pieces,
rub-
ber,or
other
plastic
parts
.
Polishing
Use
paintpolish
only
if
the
finish
assumes
a
dull
lock
after
long
service
.
Polish
can
beused
to
remove
tar
spots
and
tar-
nish,
but
afterwards
a
coat
of
wax
should
be
applied
to
protect
the
clean
finish
.
Do
not
use
abrasive
polish
or
cleaners
on
alu-
minum
trimor
accessories
.
BODYAND
INTERIOR
MAINTENANCE
Cylinder
Head
and
Valvetrain
The
aluminum
cylinder
head
uses
chain-driven
double
overhead
camshafts
and
four
valves
per
cylinder
.
See
Fig
.
1
.
Tha
rvfinriar
hand
nmnlnve
n
ernceflnier
rineinn
fnr
nronter
Tar
spots
canbe
removed
with
a
bugand
tar
remover
.
Never
use
gasoline,
kerosene,
nail
polish
remover,
or
other
unsuitable
solvents
.
Insect
spots
also
respond
to
tar
remover
.
A
bit
of
bak-
ing
soda
dissolved
in
the
wash
water
will
facilitate
their
removal
.
This
method
can
also
beused
to
remove
spotting
from
tree
sap
.
Interior
Care
Dirt
spots
can
usually
be
removed
with
lukewarm
soapy
wa-
ter
or
a
dry
foam
cleaner
.
Use
spot
remover
for
grease
and
o¡I
spots
.
Do
not
pour
the
(quid
directly
on
the
carpetor
fabric,
but
dampen
a
clean
cloth
and
rub
carefully,starting
at
the
edge
of
the
spot
and
working
inward
.
Do
not
use
gasoline,
naptha,
or
other
flammable
substances
.
Leather
Upholstery
and
Trim
Leather
upholstery
and
trim
should
be
periodically
cleaned
using
a
slightly
damp
cotton
or
wool
cloth
.
The
idea
is
to
get
rid
of
the
dirtin
the
creases
and
pores
that
can
cause
brittleness
and
premature
aging
.
On
heavily
soiled
areas,
usea
mild
deter-
gent
(such
as
Woolite®)
or
other
specially
formulated
leather
r
cleaners
.
Use
two
tablespoons
to
one
quart
of
cold
water
.
Dry
the
trim
and
upholstery
completely
using
a
soft
cloth
.
Regular
use
of
agood
quality
leather
conditioner
will
reduce
drying
and
crackingof
the
leather
.
1
.
Camshafts
2
.
Rocker
arms
3
.
Hydraulic
valve
adjusters
(HVA)
4
.
Valve
and
conical
valve
spring
GENERAL
.
.....
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
...
100-1
Cylinder
Block
and
Crankshaft
.
.
.
.
.
.
.
.
.
...
100-1
Connecting
Rods
and
Pistons
.
.
.
.
.
.
.
.
.
.
.
.
.
100-1
Cylinder
Head
and
Valvetrain
.
.
.
.
.
.
.
.
.
.
.
.
.
100-2
VANOS
(Variable
Valve
Timing)
.
.
.
.
.
.
.
.
...
100-2
DISA
(Dual
Resonance
Intake
System)
.
.
.
.
.
100-3
Engine
Management
System
.
.
.
.
.
.
.
.
.
.
.
.
.
100-3
Ignition
......
.
.
.
.........
.
.
.
.
.
.
.
.
.
.
.
.
100-5
Fuel
Delivery
..
.
.
.
.....
.
...
.
.
.
.
.
.
.
.
.
.
.
.
100-5
Cooling
System
.
...........
.
.
.
.
.
.....
.
.
100-5
Lubrication
System
.........
.
.
.
.
.
.
.
.
.
.
.
.
100-5
MECHANICALTROUBLESHOOTING
.
.
.
.
100-5
Warnings
and
Cautions
..
.
...
.
.
.
.
.
.
.
.
.
.
.
.
100-5
Cylinder
compression,
checking
.
.
.
.
.
.
.
.
.
.
.
100-6
EngineMechanical
Troubleshooting
Table
.
.
.
100-7
DRIVEABILITY
TROUBLESHOOTING
...
100-8
GENERAL
There
are
various
engíne
configurations
used
in
the
1992-
1998
E36
cars
.
See
Table
a
.
On
both
four-
and
6-cylinder
engines,
the
cylinder
block
is
cast
¡ron
with
integral
cyiinders
.
The
cyiinders
are
exposed
on
all
sides
to
circulating
coolant
.
The
fully
counterweighted
crankshaft
rotates
in
replaceable
split-shell
main
bearings
.
Oiiways
drilled
into
the
crankshaft
pro-
vide
bearing
lubrication
.
O¡I
seals
pressed
into
alloy
sea¡
hous-
ings
are
installedat
both
ends
of
the
crankshaft
.
100
Engine-General
Tablea
.
Engine
Specifications
ENGINE-GENERAL
100-1
On-Board
Diagnostics
(OBD)
...
.
.
.
.
.
.
.
.
.
.
.
100-8
Basic
Requirements
....
.
.
.
...
.
.
.
.
.
....
.100-11
Preventive
Maintenance
......
.
.
.
.
.
.....
100-11
Basic
Engine
Settings
..
.
.....
.
.
.
.
.
.....
100-11
Oxygen
Sensors
.
.
.
...
.
.
.
...
.
.
.
.
.
....
.100-11
Air
Flow
Measurement
and
Vacuum
Leaks
.
.100-12
Battery
Voltage
.
.
...........
.
.
.
.
.
.....
100-12
Wiring
and
Harness
Connections
.
.
.
.
.....
100-13
Ground
Connections
...
.
.....
.
.
.
.
.
.....
100-13
Fue¡
Supply
....
.
...........
.
.
..
.....
.100-14
TABLES
a
.
Engine
Specifications
...
...
...........
.
..
..
.100-1
b
.
Engine
Management
Systems
..
..
...........
..
100-5
c
.
Engine
Mechanical
Troubleshooting
..........
.
.
100-8
d
.
OBD
1
Fault
(Blink)
Codes
(1992-1995
models
only)
.
...
..
..
..........
..
.100-9
e
.
Engine
Driveability
Troubleshooting
...........
.100-15
Model
Engine
code
No
.
of
Dispiacement
Compression
Horsepower
cyiinders
liters
(cu
.
in
.)
ratio
SAE
net
@
rpm
318i/is/¡C
1992-1995
M42
4
1
.8
(109
.6)
10
.0
:1
100
@
6000
1996-1998
M44
4
1
.9
(115
.6)
~
10
.0
:1
103
@
6000
323ís/iC
1998
M52
6
2
.5
(152
.2)
10
.5
:1
168
@
5,500
325i/is/iC
1992-1995
M50
6
2
.5
(152
.2)
10
.0
:1
110
@
5,900
328i/is/iC
1996-1998
M52
6
2
.8
(170
.4)
10
.2
:1
190
@
5,300
M3
1995
S50US
6
3
.0
(182
.5)
10
.5:1
240
@
6,000
1996-1998
S52US
6
3
.2
(192
.3)
10
.5:1
240
@
6,000
Cylinder
Block
and
Crankshaft
Connecting
Rods
and
Pistons
The
forged
connecting
rods
use
replaceable
split-shell
bearings
at
the
crankshaft
endand
solid
bushings
at
the
pis-
ton
pin
end
.
The
pistonsare
of
the
three-ring
typewith
two
up-
per
compression
rings
and
a
lowerone-piece
o¡i
scraper
ring
.
Fui¡-floating
piston
pins
are
retained
with
circlips
.
GENERAL
100-2
ENGINE-GENERAL
Cylinder
Head
and
Valvetrain
The
aluminum
cylinder
head
uses
chain-driven
double
overhead
camshafts
and
four
valves
per
cylinder
.
See
Fig
.
1
.
The
cylinder
head
employs
a
crossflow
design
for
greater
power
and
efficiency
.
Intake
air
enters
the
combustion
cham-
ber
from
one
side
while
exhaust
gasses
exit
from
the
other
.
Oílways
in
the
head
provide
lubrication
for
the
camshafts)
and
valvetrain
.
Fig
.
1
.
M52
twin-cam,
4-valve-per-cylinder
engine
with
hydraulíc
lift-
ers
.
On
all
engines
exceptthe
M44
engine,
valveclearance
is
by
seif-adjusting
hydraulic
lifters
.
On
M44
engines,
instead
of
hy-
draulic
lifters,
hydraulic
pedestaisare
used
in
combination
with
roller
rocker
arms
to
actuate
the
valves
.
Hydraulic
pedes-
tals
have
the
same
function
as
hydraulic
lifters,
which
ís
to
maintain
zero
valve
clearance,
reduce
valve
noise,
and
elimí-
nate
routíne
adjustment
.
See
Fig
.
2
.
VANOS
(Variable
Valve
Timing)
GENERAL
1
.
Camshafts
2
.
Rocker
arms
3
.
Hydraulic
valve
adjusters
(HVA)
4
.
Valve
and
conical
valve
spring
4
Fig
.
2
.
Cross
sectionof
M44
twin-cam,
4-valve-per-cylinder
head
.
Note
function
of
hydraulíc
pedestal
in
combination
with
rock-er
arm
(with
roller
bearing
for
reduced
friction)
.
The
main
components
of
the
VANOS
system
arethe
piston
housing
with
integral
spool
valve
and
solenoid,
and
the
modi-
fied
intake
camshaft
and
sprocket
assembly
.
See
Fig
.
3
.
1993
and
later
6-cylinder
engines
are
equipped
with
a
vari-
B11001
able
intake
valve
timing
system,
known
as
VANOS
(from
the
German
words
Variable
Nockenwellen
Steuerung)
.
The
Fig
.
3
.
VANOS
(variable
intake
valve
timing)
systemusedon
M52
en-
VANOS
system
electro-hydraulically
adjusts
intake
valve
tim-
gine
.
When
solenoid
is
actuated,
oíl
pressure
is
directed
to
ingfor
enhanced
mid-range
performance
.
The
VANOS
sys-
front
side
of
gear
cup
piston
.
This
forces
gear
cup
finto
camtem
is
controlled
by
the
engine
control
module
(ECM),
using
shaft
to
advance
intake
valve
timing
.
enginespeed,engine
load
and
engine
temperature
asthe
pri-
mary
inputs
.
When
the
engine
is
running,
the
piston
housing
is
supplied
with
pressurized
engine
oil
víathe
solenoid-actuatedspool
At
low
speeds,
the
intake
valves
open
late
to
ensure
smooth
valve
.
Depending
on
the
position
of
the
spool
valve,
oil
isdi
engine
operation
.
At
mid-rangespeeds,
thevalves
open
early
rected
to
either
the
front
or
back
side
of
the
gear
cup
piston
.
(valvetiming
advanced,
VANOS
actuated)
for
increased
torque,
improved
driveability,
and
reduced
emissions
.
And
at
When
the
solenoid
isin
the
off
position,
engine
oíl
is
direct-
high
speeds,
the
valves
again
open
late
for
optimum
power
ed
to
the
back
side
of
the
piston
.
This
holds
the
gear
cup
for-
and
performance
.
ward
and
valve
timing
is
maintained
at
the
normal
"late"
position
.
When
the
solenoid
is
energized,
the
spoolvalve
is
moved
forward
and
oil
pressure
is
directed
to
the
front
side
of
the
piston
.
This
in
turn
moves
thegear
cup
further
into
the
camshaft
secondary
drive,
causing
thecamshaft
to
"advance"
12
.5°
.
The
helical
gears
are
cut
so
that
forward
motion
of
the
gear
cup
is
transiated
into
rotational
motion
of
the
camshaft
.
See
117
Camshaft
Timing
Chain
for
testing
and
repair
infor-
mation
on
the
VANOS
system
.
DISA
(Dual
Resonance
Intake
System)
DISA,usedon
4-cylinder
engines,
is
a
dual
intake
runner
system
that
effectively
provides
the
advantages
of
both
short
and
long
intake
runners
within
the
same
engine
.
For
best
per-
formance,
long
intake
runners
aremost
beneficial
atlow-
and
mid-engine
speeds
(below
4,200
rpm),
and
short
intake
run-
ners
enhance
torque
at
high
engine
speeds
(above4,200
rpm)
.
NOTE-
The
term
DISA
comes
from
the
German
words
Differ-
enzierte
Sauganlage,
and
can
roughty
be
transiated
as
a
differing
intake
manifold
configuration
.
The
DISA
solenoid
valve
is
controlled
by
the
DME
control
module,
using
engine
speed
as
the
primary
input
.
The
main
components
of
the
system
are
the
modified
twin-section
in-
takemanifoldwith
change-over
valve,
the
twin-barrel
throttle
body,
and
the
electrical/pneumatic
actuating
components
.
See
Fig
.
4
.
r
I
I
I
?
,
in
UpPer,
take
-1
manifold
1
-1
Throttle
housing
(Heated)
q
:lZU
Fig
.
4
.
DISA
system
components
.
DISA
changes
the
intake
runner
length
based
on
engine
speed
.
The
DISA
system
electro-pneumatically
changes
the
intake
runner
length
through
the
twin-section
intake
manifold
and
a
change-over
butterfly
valve
.
The
change-over
valve
is
located
at
a
point
in
the
intake
manifold
where
four
pipes
come
into
two
.
When
the
change-over
valve
is
closed,
the
4-way
primary
intake
manifold
and
the
2-way
ram
air
manifold
areconnected
to
make
the
"long"
configuration
.
When
the
change-overvalve
opens,
intake
air
flow
is
redirected
through
only
the
short
4-
way
primary
intake
manifold
.
The
change-over
valve
is
held
in
the
normally
open
position
bya
spring
.
Thisallows
for
an
open
valve
in
the
event
of
sys-
tem
failure
.
During
low
andmid
enginespeeds,
the
DME
con-
trol
module
supplies
power
to
the
solenoid
valve,
which
in
turn
allows
vacuum
to
be
applied
lo
the
vacuum
diaphragm
.
This
causes
the
valve
to
close
(long-pipe
configuration)
.
When
en-
gine
speed
reaches
approximately
4,800
rpm,
the
DME
con-
trol
module
electrically
signals
the
solenoid
valve
and
the
valve
opens,
creating
the
short
pipe
configuration
:
Further
detafs
on
DISA
canbefound
in
130
Fuel
Injection
.
Engine
Management
System
Al¡
enginescoveredby
this
manual
usean
advanced
engine
management
system
called
Digital
Motor
Electronics
(DME)
.
In
the
DME
system,
advancedOn-Board
Diagnostics
(OBD),
fuel
injection,
ignition,
and
otherfunctions,
are
combined
under
the
control
of
theEngine
Control
Module
(ECM)
.
See
Fig
.
5
.
-
Lower
intake
manifold
DISAvacuum
'
~servo
EíY1z
ENGINE-GENERAL
100-
3
le
-
DISA
solenoid
valve
0012591
/
with
butterfly
va¡
GENERAL
100-4
ENGINE-GENERAL
'
TEMP
PRECAT
POST
CAT
OXYGENSENSOR
HEATING
#
.
THROTTLE
POSITION
FUEL
INJECTOR
CONTROL
(SEQUENTIAL)
OPERATING
POWER
00
CAMSHAFT
POSITION
SENSOR
ECM
I
MAIN
GROUND
RELAY
J_
-
AC
COMPRESSOR
RELAY
CONTROL
TERMINAL
15
MEMORY
POWER
FUEL
PUMP
RELAY
CONTROL
AUX
GROUND
P
CRANKSHAFT
POSITION
dESENSOR
INTAKE
AIR
ENGINE
COOLANT
TEMP
FUEL
TANK
PRESSURE
SENSOR
S-EML
S-MSR
ASC
S-ASC
VEHICLE
SPEED
LOW
FUEL
LEVEL
A/C
SWITCH
ON
(AC)
E36
IHKA
COMPRESSOR"ON"
SIGNAL
(KO)
INDIVIDUAL
SERIAL
NUMBER
MS41
.1
SECONDARY
AIR
1NJECTION
AIR
PUMP®
RELAY
CONTROL
IDLE
CONTROL
VALVE
'M
FUEL
INJECTION
(TI)
ENGINE
SPEED
(TD)
Fig
.
5
.
Siemens
MS
41
.1
OBD
II
engine
management
systemusedon
1996
and
later
M52
engines
.
GENERAL
IGNITION
COILS
CONTROL
L
r"Q
if~
CIYVFIYC
CHE
AMP
CONTROL
ENGINE
THROTTLE
POSITION
6
ECM
RELAY
CONTROL
ASC
THROTTLE
..
:
.
.
..
-11
1Q\\\
POTENTIOMETER
POWER
CAN
TCM
II
SCAN
(DES
;
ER
DIAGNOSIS
OBD
II
I
II
GENERIC
SCANTOOL
0012596
100-6
ENGINE-GENERAL
Cylinder
compression,
checking
A
compression
tester
is
needed
to
make
a
compression
test
.
To
obtain
accurate
test
results,
the
battery
and
starter
must
be
capable
of
cranking
the
engine
at
250-300
rpm,
and
theen-
gine
should
be
at
normal
operating
temperature
.
Use
com-
pressed
air
to
clean
aroundthe
spark
plugs
before
removal
.
1
.
Disable
the
ignítion
system
by
removing
the
engine
management
system
main
relay
and
the
fuel
pump
re-
¡ay
.
See
Fig
.
6
.
WARNING
-
The
ignítion
system
produces
high
voltages
that
canbe
fatal
.
Avoid
contact
with
exposed
termínals
and
useextreme
caution
when
working
on
acar
wíth
the
ignítion
switched
on
or
the
engine
running
.
Fuel
DM
E
pump
main
re
ay
rel
ay
o
oa
ooa
.,
o00
oao
Fig
.
6
.
Engine
management
relays
in
power
distribution
box
inleft
rear
of
engine
compartment
.
CAUTION-
"
On
OBD
11
cars,
making
a
compression
test
may
causea
faultto
set
in
the
ECM
and
may
also
il-
luminate
the
Check
Engine
light
.
The
light
can
only
be
tumed
out
using
special
scan
tool
equip-
ment,using
eíther
the
BMW
specialservíce
tool
or
using
a
"generic"
OBD
11
scan
tool
.
Discon-
necting
the
battery
will
not
erase
the
fault
mem-
orynor
turn
outthe
light
.
0013034,
0012630
Fig
.
7
.
Remove
spark
plug
wires
from
spark
plugs
on
4-cylinder
en-
gine
using
special
tool
.
Tool
is
stored
under
cover
at
rear
of
cylinder
head
(arrow)
.
Fig
.
8
.
Remove
engine
cover
on
6-cylinder
engine
byprying
off
nut
covers
and
removing
nuts
(A)
.
Be
careful
not
to
let
rubber
in-
sulators
fall
off
as
cover
is
removed
(arrows)
.
4
.
On
6-cylinder
engines,
disconnect
the
harness
connec-
tors
from
the
ignítion
coils
by
lifting
the
retaining
clip
.
Remove
the
coil
mounting
nuts
andremove
the
six
coils
.
See
Fig
.
9
.
Remove
the
sparkplugs
.
"
Failure
to
remove
the
main
relay
or
attempting
to
disable
the
ignítion
system
by
other
methods
may
resultin
damage
to
the
engine
control
module
.
NOTE-
Used
sparkplugs
should
be
reinstalled
in
the
same
cyl-
2
.
On
4-cylinder
engine
:
Remove
plastic
engine
cover
from
inder
fromwhich
they
were
removed
.
top
of
cylinder
head
.
Disconnect
spark
plug
wires
and
re-
move
spark
plugs
.
See
Fig
.
7
.
5
.
Insta¡¡
the
compression
gauge
in
the
first
cylinder's
3
.
On
6-cylinder
engine
:
Remove
top
engine
coverby
pry-
spark
plug
hole,
tight
enough
to
form
a
good
seal
.
ing
off
nut
covers
and
removing
mounting
nuts
.
See
Fig
.
8
.
MECHANICAL
TROUBLESHOOTING