1995 BMW M3 pressure switch

Please
read
these
warnings
and
cautions

before
proceeding
with
maintenance
and
repair
work
.

WARNING-



"
Friction
materials
(such
as
brake
pads
or
shorts
or
clutchdiscs)
contain
asbestos
fibers
or
other
friction
materials
.
Do
notcreate
"
See
also
Cautionson
page
viü



dustby
grinding,
sanding,
orby
cleaning
with
compressed
air
.

"
Some
repairs
may
be
beyond
your
capability
.
If
you
lack
the



Avoid
breathing
dust
.
Breathing
any
friction
material
dust
can
lead

skills,
tools
and
equipment,
or
a
suitable
workplace
for
any
proce-



to
serious
diseases
and
may
result
in
death
.

duredescribed
in
this
manual,
we
suggestyou
leave
such
repairs



"
Batteries
give
off
explosive
hydrogen
gas
during
charging
.
to
an
authorized
BMW
dealer
service
department
or
other
quali-



Keep
sparks,
lighted
matches
and
open
flame
away
from
the
top
fied
shop
.



of
the
battery
If
hydrogen
gas
escaping
from
the
cap
vents
is

"Do
not
re-use
any
fasteners
that
are
worn
or
deformed
in
normal



ignited,
it
will
ignite
gas
trapped
in
the
cells
and
cause
the
battery

use
.
Many
fasteners
are
designed
to
be
used
only
once
and



to
explode
.

become
unreliable
and
may
fail
when
used
a
second
time
.
This



"
Connect
and
disconnect
battery
cables,
jumper
cablesora
bat-
includes,
but
is
not
limited
to,
nuts,
bolts,
washers,
self-locking
nuts
or
bolts,
circlips
and
cotterpins
.
Always
replace
these
fasteners

with
new
parts
.
"Do
not
quick-charge
the
battery
(for
boost
starting)
for
longer
"
Never
work
under
a
lifted
car
unless
it
is
solidly
supportedon



than
one
minute
.
Wait
at
least
one
minute
before
boosting
the
bat-
stands
designed
for
the
purpose
.
Do
not
support
a
car
on
cinder



tery
a
second
time
.
blocks,
hollow
tiles
or
other
props
that
may
crumble
under
contin-

uous
load
.
Never
work
under
acar
that
is
supported
solely
by
a



"Do
not
allow
battery
charging
voltage
to
exceed
16
.5
volts
.
If
the

jack
.
Never
work
under
thecar
while
the
engine
is
running
.



battery
beginsproducing
gas
or
boiling
violently,
reduce
the
charg-
ing
rate
.
Boosting
a
sulfated
battery
at
a
high
charging
rate
can
"
If
you
are
going
to
work
under
acar
on
the
ground,
make
sure



cause
an
explosion
.
that
the
ground
is
level
.
Block
the
wheels
to
keep
the
carfrom
roll-

ing
.
Disconnect
the
battery
negative
(-)
terminal
(ground
strap)to



"
The
air-conditioning
system
is
filled
with
chemical
refrigerant,

prevent
others
from
starting
thecar
while
youare
under
it
.



which
is
hazardous
.
TheA/C
system
should
be
servicedonly
by

trained
technicians
using
approved
refrigerant
recovery/recycling
"
Never
run
the
engine
unless
the
work
area
is
well
ventilated
.



equipment,
trained
in
related
safetyprecautions,
and
familiar
with
Carbon
monoxide
kills
.



regulations
governing
the
discharging
and
disposal
of
automotive

"
Finger
rings,
bracelets
and
other
jewelry
shouldbe
removed
so



chemical
refrigerants
.

tery
charger
only
with
the
ignition
switched
off,
to
prevent
sparks
.

Do
not
disconnect
the
battery
while
the
engine
is
running
.

that
theycannot
cause
electrical
shorts,
get
caught
in
running



"
Do
not
expose
any
partof
the
A/Csystem
to
high
temperatures
machinery,
or
be
crushed
by
heavy
parts
.



suchas
open
flame
.
Excessiveheat
will
increase
system
pressure

"
Tie
long
hair
behind
your
head
.
Do
not
wear
a
necktie,
a
scarf,



and
may
cause
the
system
to
burst
.

loose
clothing,
or
a
necklace
when
you
work
near
machine
tools
or



"
Some
aerosol
tire
inflators
are
highly
flammable
.
Be
extremely
running
engines
.
If
your
hair,
clothing,
or
jewelry
were
to
get
caught



cautious
when
repairing
a
tire
that
may
havebeen
inflated
using
in
the
machinery,
severe
injury
could
result
.



an
aerosol
tire
inflator
.
Keep
sparks,
open
flame
or
other
sources

"
Do
not
attempt
to
work
onyourcar
if
you
do
not
feel
well
.
You



of
ignition
away
from
the
tire
repair
area
.
Inflate
and
deflate
the
tire

increase
the
danger
of
injury
toyourself
and
others
if
you
are
tired,



at
least
four
times
before
breaking
the
bead
from
therim
.
Com-

upset
or
have
takenmedication
or
any
other
substance
that
may



Pletely
remove
the
tire
from
the
rim
beforeattempting
any
repair
.

keep
you
from
being
fully
alert
.

"
Illuminate
your
work
areaadequately
but
safety
.
Use
a
portable

safety
light
for
working
inside
or
under
thecar
.
Make
surethe
bulb

is
enclosedbya
wire
cage
.
The
hot
filament
of
an
accidentally
bro-

ken
bulb
can
ignite
spilled
fuel
or
oil
.

"
Catch
draining
fuel,
oil,
orbrake
fluid
in
suitable
containers
.
Do

not
use
food
or
beverage
containers
that
mightmislead
someone

into
drínking
from
them
.
Store
flammable
fluids
away
from
fire
haz-

ards
.
Wipe
up
spills
at
once,
but
do
not
store
the
oily
rags,
which

can
ignite
and
burn
spontaneously
.

"
Always
observe
good
workshop
practices
.
Wear
goggles
when

youoperate
machine
tools
or
work
with
battery
acid
.
Gloves
or

other
protectioeclothing
should
be
worn
whenever
thejob
requires

working
with
harmful
substances
.

"
Greases,
lubricants
and
other
automotive
chemicals
contain

toxic
substances,
many
of
which
are
absorbed
directly
through
the

skin
.
Read
the
manufacturer's
instructions
and
warnings
carefully
.

Use
hand
andeye
protection
.
Avoid
direct
skin
contact

"
Cars
covered
by
this
manual
are
equipped
with
a
supplemental

restraint
system
(SRS),
that
automatically
deploys
an
airbag(s)
in

theevent
of
a
frontal
ímpact
.
The
airbag(s)
is
inflated
byan
explo-

sive
device
.
Handled
improperly
or
without
adequate
safeguards,

can
be
accidently
activated
and
cause
serious
injury
.

"
The
ignition
system
produces
high
voltages
that
can
be
fatal
.

Avoid
contact
with
exposed
terminals
and
use
extreme
care
when

working
ona
car
with
the
engine
running
or
the
ígnition
switched
on
.

"
Place
jack
stands
only
at
locations
specified
bymanufacturer
.

The
vehicle
lifting
jacksupplied
with
the
vehicle
is
intended
for
tire

changes
only
.
A
heavy
duty
floor
jack
shouldbe
used
to
lift
vehicle

before
installing
jack
stands
.
See
010
Fundamentals
for
theDo-
.

it-Yourself
Owner
.

"
Battery
acid
(electrolyte)
can
cause
severeburns
.
Flush
contact

area
with
water,
seek
medical
attention
.

"
Aerosolcleaners
and
solvents
may
contain
hazardous
ordeadly
vapors
and
are
highly
flammable
.
Use
only
in
a
wellventilated

area
.
Do
not
use
on
hot
surfaces
(engines,
brakes,
etc
.)
.

"
Disconnect
the
battery
negative
(-)
terminal
(Ground
strap)



"
Do
not
remove
coolant
reservoir
or
radiator
cap
with
theengine

whenever
you
work
on
the
fuel
system
orthe
electrical
system
.
Do



hot
.
Danger
of
bums
and
engine
damage
.

not
smoke
or
work
near
heaters
or
other
fire
hazards
.
Keep
an

approved
fire
extinguisher
handy
.



continued
on
next
page
vii

020-
4



MAINTENANCE
PROGRAM

L



~



~
c
.c
a



a>
mL



~



~L



L
w



a



£
'S



d
E

Maintenance
ítem



z



3



c

Engine
compartment
maintenance

Change
oil
and
oil
filter

Check
fluid
levels
(coolant,steering,
brake/clutch,
ATF)

Under
car
maintenance

Check
steeringrack
and
steeringlinkages
for
leaks
andexcess
play
.
Repair
Group
320

Inspect
brake
system
.
Check
brake
calipers,
rotors,
and
brake
pad
thíckness
.
Inspect
for
dam-
aged
hoses
and
lines,
leaks
or
damage
.
Check
hand
brake,adjust
cable
if
necessary
.
Repair
Group
340

Check
and
adjust
tire
pressures,
including
spare

Body
and
interior
maintenance

Check
operation
of
exterior
and
interior
lights,
including
glove
box
light,
engine
compartment
light,
trunk
light,
instrument
panel
lights,
horns,
headlight
flasher
anddimmer
switch
.
Check
headlight
and
driving
light
aiming
.
6
Electrical
System

Check
function/condition
of
seat
belts
.
Repair
Group
720

Check
windshield
washer
fluid
level
and
concentration,
add
as
necessary
.
Check
operation
of
washer
system
.
Check
condition
of
wiper
blades
.
Repair
Group
611

Road
Test

Check
braking
performance,
steering,
heating
and
ventilation,
manual
or
automatic
transmis-
sion,
and
mirrors

Service
Interval
Reset

Reset
service
indicator
using
specialreset
tool
.

MAINTENANCE
TABLES

Table
a
.
Oil
Service

Table
b
.
Inspection
I
Service

MAINTENANCE
PROGRAM
020-5

ad

d
d
ID

a



r



c



d
a~
;v
a
:
Q~
wE
y
a
r
E
R
:
L-



0
Maintenance
ítem



1



z



3
~



c
d

Engine
compartment
maintenance

Change
oil
and
oil
filter
.

Check
brake/clutch
fluid
leve¡

Check
battery
acid
leve¡
and
correct
asnecessary
.
Repair
Group
121

Check
engine
coolant
level
and
anti-freeze
protection
and
addasnecessary
.
Inspect
for
cooling
system
leaks
.
Repair
Group
170

Lubricate
throttie
linkage

Under
car
maintenance

Check
transmission
for
externa¡
leaks
.

Check
manual
transmission
oil
leve¡
andadd
asnecessary
.
Repair
Group
230

Check
final
drive
lubricant
and
addasnecessary
.

Check
fue¡
tank,
fuel
lines,
and
all
connections
for
leaks
.

Inspect
exhaust
system
.
Repair
Group
180

Check
steeringrack
and
steeringlinkages
.
Check
power
steering
system
for
leaks
.
Check
(luid
leve¡
.
Repair
Group
320

Inspect
brake
system
for
damaged
hoses
and
fines,
leaks
or
damage
.
Remove
calipers
and
check
brake
pad
wear
.
Check
brake
rotors
for
scoring
damage
.
Repair
Group
340

Check
parking
brake
operation,
adjust
cable
if
necessary
Repair
Group
340

Inspect
front
and
rear
suspension,
including
wheel
bearings,
for
play
.
Repair
Group
320/330

Inspect
wheelsand
tires,
including
spare,
check
tire
pressure
and
condition

Body
and
Interior
Maintenance

Lubricate
door
hinges
and
hood
latch,
hood
hinges

Check
headlight
and
driving
light
aiming
and
adjust
as
necessary
.

Check
operation
of
headlights,
parking
lights,
back-up
fights,
licenseplate
lights,
interior
lights,
glove
box
light,
engine
compartment
light,
trunk
light,
instrument
panel
lights,
turnsignals,
emer-gency
flashers,
stop
fights,
horas,
headlight
flasher
and
dimmer
switch

Replace
ventilation/A/C
micro-filter
.
Check
functionof
air
conditioning
.
Repair
Group
640

Check
function
of
seat
belts
.
Repair
Group
720

Check
tightness
of
mountfng
screws
on
airbag
front
crash
sensors
(Airbag
I)
.
Repair
Group
721

Check
windshield
washer
fluid
leve¡
and
concentration,
add
as
necessary
Check
operation
of
washer
system
.
Check
condition
of
wiperblades
.
Repair
Group
611

Tighten
nuts
and
bolts
for
door
locks
and
striker
plates

Replace
batteries
for
alarm/remote
control
in
masterkey(where
applicable)
.

Road
Test

Check
braking
performance,
steering,
HVAC,
manual
or
automatic
transmission,
and
mirrors

Service
Interval
Reset

Reset
service
indicator
using
specialreset
tool
.

MAINTENANCE
TALES

020-6



MAINTENANCE
PROGRAM

Group
310/330

Table
c
.
Inspection
II
Service

a
d

d



a



a>



0
d

a



r



.c



mm
L



m
y



L
E

ó
3
E
ó

Maintenance
ítem



l
o-



z



~



c

Engine
compartment
maintenance

Inspect
V-belt
/Poly-ribbeddrive
condition
.
Check
V-belt
tension,
if
applicable
.

Lubricate
throttle
linkage
.

Replace
air
filter
.

Change
oil
and
oil
filter
.

Replacespark
plugs
.
Repair
Group
120

Check
brake/clutch
fluid
leve¡
.

Check
battery
acid
leve¡
and
correct
asnecessary
.
Repair
Group
121

Check
engine
coolant
leve¡
and
anti-freeze
protection
and
add
asnecessary
.
Inspect
for
cooling
system
leaks
.
Repair
Group
170

Under
car
maintenance

Change
automatic
transmission
fluid
.
Repair
Group
240

Change
manual
transmission
oil
.
Repair
Group
230

Check
clutch
plate
for
wear
.
Repair
Group
210

Check
drive
axle
boots
for
leaks
.
Repair
Group
330

Change
final
drive
fluid
(1995
and
later
models
:
change
synthetic
oil
every
2nd
Inspection
II)
.

Replace
fuel
filter
.

Check
fuel
tank,
fuel
lines,
and
af
connections
for
leaks
.

Inspect
exhaust
system
.
Repair
Group
180

Check
steering
gear
and
steering
¡inkages
.
Check
power
steering
system
for
leaks
.
Check
fluidleve¡
.
Repair
Group
320

Inspect
brake
system
for
damaged
hoses
and
lines,
leaks
or
damage
.
Remove
calipers
and
check
brake
pad
wear
.
Check
brake
rotors
for
scoring
damage
.
Repair
Group
340

Check
parking
brake
operation,
adjust
cable
if
necessary
.
Check
thickness
of
parking
brake
lin-
ings
.
Repair
Group
340

Inspect
front
and
rear
suspension,
including
front
and
rear
wheel
bearings,
for
play
.
Repair

Inspect
wheels
and
tires,
including
spare,
check
tire
pressure
and
condition
.

Body
and
Interior
Maintenance

Lubricate
door
hinges
and
hood
latch,
hood
hinges
.

Check
headlight
and
driving
light
aiming
and
adjust
asnecessary
.

Check
operation
of
headlights,
parking
lights,
back-up
lights,
licenseplate
lights,
interior
lights,
glove
box
light,
engine
compartment
light,
trunk
light,
instrument
panel
lights,
turn
signals,
emer-gency
flashers,
stop
lights,
horns,
headlight
flasher
anddimmer
switch
.

Check
active
check
control
panel
forfauits
(where
applicable)
.
6
Electrical
System

MAINTENANCE
TABLES

Continued
on
next
page

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

ignition

Table
b
.
Engine
Management
Systems



engine
has
high
mileage
.

Engine



1
System

4-cylinder
engines
M42
(1992-1995)



Bosch
DME
Ml
.7
M44
(1996-1998)



Bosch
DME
M5
.2
(OBD
II)

6-cylinder
engines
M50
(1992)



Bosch
DME
M3
.1
M50
VANOS
(1993-1995)



Bosch
DME
M3
.3
.1
M52
(1996-1998)



Siemens
MS41
.1
(OBD
II)
S50US
(1995)



Bosch
DME
M3
.3
.1
S52US
(1996-1998)



Siemens
MS41
.1
(OBD
II)

Both
the
4-cylinder
and
6-cylinder
engines
use
a
distributor-

less
ignition
system
with
individual
ignition
coils
for
each
cylin-

der
.

FuelDelivery

Pressurized
fuel
from
the
in-tank
fuel
pump
is
injected
via

solenoid-type
fuel
injectors
.
The
ECM
controls
the
opening

and
closing
of
the
injectors
by
switchingthe
ground
side
of

each
injector
circuit
.
The
exact
amount
of
fuel
injected
is
de-

termined
by
the
amount
of
timethe
injectors
are
open
.

Cooling
System

Whenever
the
engine
is
running,
acoolant
pump
circulates

coolant
through
the
engine
and,
if
either
heater
control
valves

are
open,
through
the
heater
core
in
the
passenger
compart-

ment
.
The
coolant
absorbs
excess
heat
and
carries
it
to
the
ra-

diator
where
it
is
transferred
into
the
passing
airstream
.
A

thermostat
controls
the
flow
of
coolant
through
the
radiator

based
on
engine
temperature
.

Lubrication
System

The
lubrication
system
is
pressurized
whenever
theengine

is
running
.
The
oil
pump
draws
oil
through
a
pickup
in
the
bot-

tom
of
the
oil
pan,thenforces
it
through
a
replaceable
oil
filter

and
finto
the
engine
oíi
passages
.

On
4-cylinder
engines,
the
oil
pump
is
mounted
to
the
front

engine
cover
.
On
6-cylinder
engines,thechain-driven
oil

pump
is
bolted
to
the
bottom
of
the
cylinder
block
.

A
pressure
relief
valve
limits
the
maximum
system
pres-

sure
.
A
bypass
valve
prevents
the
oil
filter
from
bursting
and

insures
engine
lubrication
should
the
filter
become
plugged
.

See
119
Lubrication
System
for
additional
information
.

ENGINE-GENERAL
100-
5

Various
versions
of
DME
systems
are
usedon
thecars
cov-



MECHANICAL
TROUBLESHOOTING
ered
by
this
manual
.
See
Table
b
.
Each
system
is
highly
adaptive
to
compensate
for
things
suchasengine
wear
and



When
troubleshooting
an
engine
that
fails
to
start
or
runs
vacuum
leaks
.



poorly,
first
check
its
mechanical
condition-particularly
if
the

Warnings
and
Cautions

For
personal
safety,
as
well
asthe
protection
of
sensitive
electronic
components,
the
following
warnings
and
cautions
must
be
adhered
to
during
all
troubleshooting,
maintenance,
and
repairwork
.

WARNING
-

"
The
ignition
system
produces
high
voltages
that
can
be
fatal
.
Avoid
contact
with
exposed
termi-
nals
anduse
extreme
caution
when
working
on
a
car
with
the
ignition
switched
on
or
the
engine
running
.

"
Do
not
touch
or
disconnect
any
high
voltage
ca-
bles
from
the
coil,
distributor,
orspark
plugs
while
the
engine
is
running
or
being
cranked
by
the
starter

"
Connect
and
disconnect
the
engine
manage-
ment
system
wiring
and
test
equipment
leads
only
when
the
ignition
is
switched
off
.

"
Gasoline
is
highly
flammable
and
its
vapors
are
explosive
.
Do
not
smoke
or
work
on
a
car
near
heaters
or
other
fire
hazards
when
diagnosing
and
repairing
fuel
system
problems
.
Have
a
fire
extínguisher
available
in
case
of
an
emergency
.

"
Disconnecting
the
battery
may
erase
fault
code(s)
stored
in
control
module
memory
.
Using
special
BMW
diagnosnnc
equipment,
check
for
fault
codes
prior
to
disconnecting
the
battery
cables
.
If
the
Check
Engine
lightis
illuminated,
see
On-

Board
Diagnostics
(OBD)
forfault
code
infor-
mation
.
If
any
other
system
faults
havebeen
de-tected
(indicated
byan
illuminated
warning
light),
see
an
authorized
BMW
dealer
.

CAUTION-

"
Prior
to
disconnecting
the
battery,
read
the
bat-
tery
disconnection
cautions
gíven
at
the
front
of
this
manual
on
page
viii
.

"
Do
notconnect
any
test
equipment
that
delivers
a
12-volt
power
supply
to
terminal15
(+)
of
the
ignition
coil
.
The
current
flow
may
damage
the

ECM
.
In
general,
connect
test
equipment
only
as
specified
by
BMW,
this
manual,
or
the
equip-
ment
maker
.

"
Do
not
disconnect
the
battery
with
the
engine
running
.
Do
notrunthe
engine
with
any
of
the
sparkplug
wires
disconnected
.

MECHANICAL
TROUBLESHOOTING

100-
1
4
ENGINE-GENERAL

0013131

Fig
.
13
.
Main
chassis
ground
(arrow)
inleft
front
of
engine
compart-
ment
.

Fuel
Supply

For
the
engine
tostart
and
run
properly,
the
injection
sys-

tem
must
deliver
fuel
in
precise
proportion
to
the
amount
of
air

entering
the
engine
.
Todo
this,
the
injection
system
requires

an
unrestricted
supply
of
fuel
from
the
fuel
pump
.

If
the
fuel
pump
is
not
working,
the
engine
will
notrun
.
If
the
fuel
filter
or
a
fuel
line
is
restricted,
the
engine
may
run
poorly
.
If
the
restriction
is
severe
enough
the
engine
will
not
start
.
lf

fuel
delivery
problemsare
suspected,
perform
the
tests
de-

scribed
in
160
Fuel
Tank
and
Fuel
Pump
.

The
fuel
pressure
created
by
the
fuel
pump
is
controlled
by
a
pressure
regulator
thatreturns
excess
fuelto
the
tank
.
Any
change
in
fuel
pressure
will
cause
a
change
in
the
base
air-fuel

mixture
delivered
to
the
engine
.
If
the
fuel
pressure
is
too
low,
the

base
air-fuel
mixture
will
be
lean
.
lf
the
fuel
pressure
is
too
high,
the
base
mixture
will
be
rich
.
Fuel
pressure
tests
aredescribed
in
160
Fuel
Tank
and
Fuel
Pump
and130
Fuel
Injection
.

NOTE-

Fuel
pressure
tests
require
a
pressure
gauge
.
If
thistoolís
not
avaílable,
the
tests
can
be
performed
byan
authorized
BMW
dealer
or
other
qualified
shop
.

DRIVEABILITY
TROUBLESHOOTING

Properly
operating
fuel
injectors
play
amajor
role
in
fuel
de-

livery
.
The
DMEECM
switches
the
injectors
on
and
off
at
the

negative
(-)
or
ground
side
of
the
connectors
.
Posítíve
(+)
bat-

tery
voltage
is
always
present
at
the
connectors
when
theen-

gine
is
running
.
An
injector
that
fails
or
loses
power
will
not

open,
creating
a
lean
air-fuel
mixture
and
causing
the
engine
to

run
poorly
when
coldor
stumble
on
acceleration
.
An
injector

that
shorts
to
ground
will
remain
open
constantly
when
the
en-

gine
is
running,
creating
a
richair-fuel
mixture
that
can
dilute

engine
oil,
foul
the
spark
plugs,
cause
a
rough
idle,
and
damage

the
catalytic
converter
.

Table
e
lists
additional
symptoms
of
common
engine
drive-

ability
problems,
their
probable
causes,
and
the
suggested

corrective
actions
.
The
entries
in
boldtype
in
the
corrective

action
column
indicate
the
repair
groups
where
applicable
test

and
repair
procedures
can
befound
.

NOTE-

Most
of
the
symptoms
fisted
in
Table
e
will
also
cause
the
Check
Engine
light
to
come
on
.
If
the
light
is
on,

check
for
any
stored
faults
as
the
first
step
ín
trouble-
shooting
driveability
complaints
.

113-4



CYLINDER
HEAD
REMOVAL
AND
INSTALLATION

20
.
Disconnect
main
engine
wiring
harness
connector
.
La-

bel
and
disconnect
harness
connectors
for
crankshaft

and
camshaft
sensors
.
See
Fig
.
8
.

0012504

Fig
..
Crankcase
vent
valve
(A),
camshaft
and
crankshaft
sensor
harness
connectors
(B),
locating
bushings
(C),
main
engine
wiring
harnessconnector
(D)
.
M44
engine
shown
.

NOTE-

Early
engines
do
not
havea
maín
disconnect
at
the
lower
intake
manifold
harness
.
lf
necessary,
remove
the
cable
ducting
bolts
and
set
harness
ducting
aside
.

21
.
Remové
lower
section
of
intake
manifold
.

"
Remove
Y
shaped
supportbracket
from
underside
of
manifold
.
(See
Fig
.
6
.)
"
Unbolt
support
brackets
from
alternator
and
starter
.
"
Remove
nuts
holding
manifold
to
cylinder
head
and
pull
manifold
back
until
harness
connectors
for
oil

pressure
switch
and
coolant
temperature
sensorare

accessible
.
Label
and
disconnect
connectors,
then
re-

move
manifold
and
set
aside
.

Timing
chains,
uncoupling



26
.
Lock
crankshaft
in
TDC
position
by
insertíng
BMW
spe-

22
.
On
M42
engines,
remove
thermostat
housing
from
up-



cial
tool
no
.
11
2
300
through
bore
and
into
hole
infly-

per
timing
chaincover
.



wheel
or
driveplate
.
See
Fig
.
11
.

23
.
On
late
M44
engines
(January
1997
and
later),
remove



NOTE-
secondary
air
injection
check-valve
from
front
of
engine



"
If
necessary,
remove
plug
from
locating
bore
in
lower
and
lay
aside
.



edge
of
bell
housing
to
insert
locking
tool
.

24
.
Remove
cylinder
identification
sensor
from
upper
tim-
ing
chaincover
.
Remove
upper
timing
chaincover
.
See
Fig
.
9
.

25
.
Set
engine
to
approximate
TDC
by
rotating
in
normal
operating
direction
until
camshaft
lobes
at
cylinder
no
.
1
are
facing
each
other
.
See
Fig
.
10
.

CYLINDER
HEAD,
4-CYLINDER

Fig
.
9
.



Upper
timing
chain
cover
bolts
(arrows)
.
Remove
secondary
air
injection
check
valve
fromhose
(A)
on
M44
engine
.
Re-
move
cylinder
identification
sensor
from
chaincover
(B)
.

0011998

Fig
.
10
.
Engine
set
to
approximate
TDC
.
Cylinder
no
.
1
camshaft
lobes
face
in
and
arrows
on
sprockets
poínt
up
(arrows)
.

"
Confirm
that
the
locking
tool
has
been
correctly
in-
stalled
by
trying
to
rotate
the
crankshaft
.

27
.
Lock
camshafts
at
TDC
by
mounting
BMW
specíal
tool
no
.
113
240
over
square
ends
of
camshafts
.
See
Fig
.
12
.

NOTE-

Check
that
tool
is
squarely
seated
on
cylinder
head
gasket
surface
.
If
necessary,
rotate
camshafts
slightly
using
an
open-end
wrench
at
hex
oncamshafts
.