
RER
Knock
Sensor
Knock
Sensor
(cyl
.1-3)
(cyl
.4-6)
Batteryvoltage
IMIRING
in
run
or
start
COLORCODE
(
via
ignition
switch
termina¡
15)
BK
BLAOK
BR
BROWN
RD
-
RED
YL
-
YELLOW
GN
"
GREEN
EL
-
BLUF
VI
-
VIOLET
GY
-
GREY
WT
-
WHITE
PK
-
PINK
4
.0
GN
l1/1j\
I'1
/~/1r1
l\r1
1
55
so
si
52
23
25
24
56
54
1
Power
input
Power
input
III
O
Engine
Control
Module
(Bosch
DMEM13
.1)
II
grounds
P
ower
input
Main
relaY
control
I
70
__
_
71
69
17
28
43
16
-34---"-6
26
27
____________________________________________
From
main
relaterminal
87
(battery
voltage
in
run
or
start
.5
YL
Camshaft
Position
Sensor
Ground
(RH
rearof
enginecompartment,
rear
of
shock
tower)
.5
BK
Crankshaft/rpm
Position
Sensor
Fig
.
16
.
Bosch
DME
M33
.1
ignition
system
círcuit
for
1993-1995
M50
engines
with
VANOS
.
IGNITION
SYSTEM
120-11
Ground
=
(RH
rear
of
engine
compartment,
back
sideof
shock
tower)
Batteryvoltage
Battery
voltage
in
run
or
start
in
run
or
start
(
via
ignition
switch
(
via
main
relay
terminal
15)
terminal
87)
1
.0
RD
11506a
.5
BR
Batteryvoltage
at
all
times
to
Main
relay
(terminal
85)
IGNITION
SYSTEM
SCHEMATICS

120-12
IGNITION
SYSTEM
Warning
.
Lethal
voltagepresent
Battery
voltage
in
run
or
start
(via
ignitíon
switch
terminal
15)
I
t
IGNITION
SYSTEM
SCHEMATICS
Battery
voltage
in
run
or
start
(
via
ignition
switchterminal
15)
WIRING
COLOR
CODE
Knock
Sensor
Knock
Sensor
Crankshaftlrpm
Camshaft
(cyl
.
1-3)
(cyl
.
4-6)
Position
Sensor
Position
-
-
Sensor
-
Fig
.
17
.
Siemens
MS
41
.1
ignition
systemusedon1996
and
later
6-cylinder
engines
.
1.0
BR
PQ
1
.08~1
.0BKIRD
/1
.0BK/YL
'10BK/BL
'1
.03KIGN
10BKNI
4
1D
BK
-
BLACK
BR
-
BROWN
RD
-
RED
YL
-
YELLOW
GN
-
GREEN
BL
-
BLUE
VI-
VIOLET
GY
-
GREY
WT
-
WHITE
PK
-
PINK
Batteryvoltage
in
run
or
start
(via
main
relay
terminal
87)
!1
rl
1.0
B~
^
1.0
BK/RD
^
1.0
BKIYL
^
1
.0
BK/BL
n
1.0
BK/GN
n
1
.0
BKIVI
%~
r
-------
--------------_____________----_______-_-____
49
29
1
30
2
31
3
8754
1
power
input
Power
input
I
1
Engine
Control
Module
(Siemens
MS
41
.1)
1
1
grounds
1
n
1
Powerinput
Mainrelaycontrol
1
1-
57
___
58
_
59
_
__
63
_
38
83
48
40
64
43
65
41
28
32
34
4
26
73
1
-
-----------
-
_-----
-
------
_
------
-
------
-
---
-
.5Y1-
.5BKY.5GNY.5BRY
Y
.35BKY
1
Y
Y
.35BKY/Y35YY
75
.18R/
.5YL-1
1'
.
Batteryvoltage
at
all
times
to
Main
relay
(terminal
85)
Ground
v
(RH
rear
of
engine
Z
compartment,
rear
=
of
shock
tower)
Ground
(RH
rear
of
enginecompartment,
rearof
shock
tower)
0012731

2
.
Remove
cooling
duct
or
terminal
cover
from
rear
of
al-
2
.
Remove
air
cleaner
upper
section
with
mass
air
flow
ternator
.
sensor
.
3
.
Check
for
battery
voltage
between
ground
and
terminal
3
.
Remove
terminal
cover
from
rear
of
alternator
.
Discon
B+
at
back
of
alternator
.
Then
turn
ignition
on
and
nect
wiring
.
check
for
battery
voltage
between
terminal
D+
and
ground
.
See
Fig
.
3
.
lf
voltage
is
not
present
at
either
4
.
Remove
drive
belt
from
alternator
pulley
.
See
020
point,
check
wiring
for
faults
.
Maintenance
program
.
001
¡987
Fig
.
3
.
Terminal
B+
is
supplied
battery
voltage
directly
from
the
bat-
tery
.
Terminal
D+
is
supplied
battery
voltage
via
the
charge
warning
bulb
when
thekey
is
on
or
the
engine
is
running
.
4
.
lf
no
faults
are
foundup
to
thispoint,test
alternator
out-
put
using
a
load
tester
.
5
.
If
a
load
tester
is
not
available,
a
crude
output
test
can
be
done
by
running
engine
at
about
2000
rpmand
turn-
ing
on
electrical
loads
(fans,
lights
and
rear
window
de-
froster,
wipers)
.
With
al¡
accessories
on,
battery
voltage
should
be
above
12
.0
VDC
.
A
replacement
alternator
should
have
the
same
rating
as
the
original
.
Alternator
manufacturer
and
ampere
rating
are
normally
marked
on
the
alternator
housing
.
1
.
Disconnect
negative
(-)
battery
cable
.
CAUTION-
Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
vi¡¡
.
BATTERY,
STARTER,
ALTERNATOR
121-
5
6
.
Remove
upper
and
lower
mounting
bolts
and
lift
out
al-
ternator
.
See
Fig
.
4
.
NOTE
-
If
reusing
drive
belt,
mark
direction
of
rotation
on
belt
before
removing
.
5
.
On
M44
engine
with
hydraulic
belt
tensioner
:
Remove
tensioner
idler
pulley
(upper
roller)
from
alternator
bracket
.
Fig
.
4
.
Alternator
mounting
bolts
(arrows)
.
O
u
J
S
v~~
U
I
1
i
n
-12
.22
Alternator,
removing
and
installing
7
.
Installation
is
reverse
of
removal
.
Install
drive
belt
as
(4-cylinder
engine)
described
in
020
Maintenance
Program
.
Tightening
Torques
"
D+
vire
to
alternator
(M6
nut)
.
...
.
.
.
7
Nm
(53
in-lb)
"
B+
wire
to
alternator
(M8
nut)
..
.
.
.
.
.
13
Nm
(10
ft-Ib)
"
Pulley
to
alternator
(M16
nut)
...
..
..
60
Nm
(44
ft-Ib)
ALTERNATOR
SERVICE

121-
6
BATTERY
STARTER,
ALTERNATOR
Alternator,
removing
and
installing
(6-cylinder
engine)
A
replacement
alternator
should
have
the
same
rating
as
the
original
.
Alternator
manufacturer
and
ampere
rating
are
normally
marked
on
the
alternator
housing
.
1
.
Disconnect
negative
(-)
battery
cable
.
CAUTION-
Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
viii
.
2
.
Remove
alternator
cooling
duct
and
air
filter
housing
assembly
from
car
.
Disconnect
wiring
from
rear
of
alter-
nator
.
3
.
Remove
radiator
cooling
fan
and
fan
shroud
.
See
170
Radiator
and
Cooling
System
.
4
.
Remove
alternator
drive
belt
from
alternator
pulley
.
On
engines
with
hydraulic
belt
tensioner,
remove
tensioner
idler
pulley
(upper
roller)
from
alternator
bracket
.
See
Fig
.
5
.
ALTERNATOR
SERVICE
Fig
.
5
.
Pry
off
cover
from
tensioner
and
then
lever
tensioner
clock-
wise
to
release
belt
tension
.
Remove
upper
roller
(A)
once
belt
ís
removed
.
NOTE-
If
reusing
drive
belt,
mark
direction
of
rotation
on
belt
before
removing
.
5
.
Remove
upper
and
lower
mounting
bolts
and
lift
out
al-
ternator
.
6
.
Installation
is
reverse
of
removal
.
Note
locating
notches
on
tensioner
idler
pulley
(upper
roller)
alternator
brack-
et
when
installing
pulley
.
Tightening
Torques
"
D+
wire
to
alternator
(M6
nut)
.......
7
Nm
(53
in-lb)
"
B+
wireto
alternator
(M8
nut)
.......
13
Nm
(10
ft-Ib)
"
Pulley
to
alternator
(M16
nut)
.......
60
Nm
(44
ft-Ib)
Voltage
regulator,
removing
and
installing
1
.
Disconnect
negative
(-)
cable
from
battery
.
NOTE-
2
.
Remove
alternator
as
described
earlier
.
The
radiator
cooling
fan
nut
(32
mm
wrench)has
left-
hand
threads
.
3
.
Remove
cooling
duct
from
rear
of
alternator
.
See
Fig
.
6
.
Alternator
.
.g-
p~
J
-..
.
Fig
.
6
.
Alternator
assemblyand
related
parts
.
Cooling
duct
0012524
4
.
Remove
voltage
regulator
mounting
screws
and
re-
move
regulator
from
alternator
.
5
.
Installation
is
reverse
of
removal
.
Clean
brush
contact
surfaces
in
alternator
and
check
brush
length
asde-
scribed
later
.

Starter,
removing
and
installing
(6-cylinder
engine
with
automatic
transmission)
The
starter
on
a
6-cylinder
car
with
automatic
transmission
ís
removed
from
above
.
It
is
necessary
to
remove
the
íntake
manifold
and
disconnect
a
number
of
electrical
harness
con-
nectors
.
1
.
Disconnect
negative
(-)
battery
cable
.
2
.
Remove
air
plenum
from
rear
of
engine
compartment
.
See640
Heating
and
Air
Conditioning
.
3
.
Remove
top
enginecovers
.
See
Fig
.
9
.
Fig
.
9
.
Remove
top
engine
cover
by
prying
out
plugs
and
removing
nuts
(A)
.
Make
sure
rubber
insulators
(B)
on
either
sideof
large
cover
do
not
fall
off
during
cover
removal
.
4
.
Remove
ignition
coil
harness
connectors
.
Remove
ground
connection
at
front
of
cylinder
head
.
5
.
Remove
two
retaining
bolts
and
lift
off
fuel
injector
har-
ness
connector
strip
.
Carefully
fold
away
all
harnesses
toward
right
side
of
engine
compartment
and
place
at
base
of
windshield
.
See
Fig
.
10
.
6
.
Remove
intake
manifold
.
See
113
Cylinder
Head
Re-
moval
and
Installation
.
7
.
Disconnect
wiring
from
starter
.
BATTERY,
STARTER,
ALTERNATOR
121-
9
Fig
.
10
.
Fuel
injection
harness
(A)
and
ignition
coíl
harness
connectors
(B)
being
lifted
off
engine
to
be
placed
at
base
ofwindshield
.
M50
engine
shown
.
Other
6-cylinder
engines
are
similar
.
8
.
Loosen
and
remove
bolts
and
nuts
fastening
starter
to
transmission
bell
housing
and/or
engine
block
.
Remove
starter
support
bracket
.
Fig
.
11
.
Starter
wiring
terminals
and
support
bracket(arrow)
.
Intake
manifold
has
been
removed
.
STARTER
SERVICE

130-2
FUEL
INJECTION
GENERAL
This
repair
group
covers
fuel
injection
system
component
testing
and
repair
.
Special
equipment
is
necessary
for
some
of
the
procedures
given
in
this
repair
group
.
If
you
do
not
have
the
equipment
required
to
do
the
job,
it
is
recommended
that
these
repairs
be
left
to
an
authorized
BMW
dealer
.
The
BMW
dealer
is
equipped
with
sophisticated
diagnostic
test
equip-
ment
that
is
capable
of
quicklypinpointing
hard-to-find
fuel
in-
jection
problems
.
NOTE-
"
Wiring
diagrams
for
the
engine
management
system,
can
be
found
at
the
rear
of
the
manual
under
Electri-
cal
Wiring
Diagrams
.
"
For
ignition
system
repairinformation,
see120
Igni-
tion
System
.
"
For
fuel
supply
system
testing
and
repair,
see160
The
engine
control
module
(ECM)
uses
electrical
signals
Fuel
Tank
and
Fuel
Pump
.
from
the
mass
air
flow
sensor,
the
air
and
coolant
temperature
sensors,
the
crankshaft
position/rpm
sensor,
the
knock
sen
Principies
Of
Operation
sors
and
the
oxygen
sensorsas
the
primary
inputs
to
electron-
ically
control
fuel
delivery
and
ignition
timing
.
There
are
five
versions
of
engine
management
systems
usedon
the
E36
cars
.
Each
has
the
same
basic
components
and
operating
principles
.
The
most
notable
difference
is
that
1996
and
later
cars
use
a
sophisticated
OBD
II-compliant
sys-
tem
.
See
Table
a
.
Table
a
.
Engine
Management
System
Variants
Engine
code/year
1
System
4-cy1inder
M42
(1
.8
I)
1992-1995
Bosch
DME
Ml
.7
M44
(1
.91)
1996-1998
~
Bosch
DME
M5
.2
(OBD
II)
6-cylinder
M50
1992
(2.5
I)
Bosch
DME
M3
.1
1993-1995
(2.5
I)
Bosch
DME
M3
.3.1
(VANOS)
M52
1996-1998
(3281-
2
.8
I)
Siemens
MS
41
.1
(OBD
II)
1998
(3231
-
2
.5
I)
Siemens
MS
41
.1
(OBD
II)
M-Power
S50US
(M3
-
3
.01)
1995
Bosch
DME
M3
.3
.1
S52US
(M3
-
3
.21)
1997-1998
Siemens
MS
41
.1
(0131)
11)
NOTE-
-
Descriptions
and
procedures
in
the
first
partof
this
re-
pairgroup
refer
to
all
the
various
engine
management
systems
.
"
Particulars
of
each
fuel
injection
system
are
treated
in
separate
sections
in
the
second
part
of
this
repair
group
.
GENERAL
Fig
.1
.
OBD
II
diagnostic
connector
locatíon
.
The
fuel
injection
system
is
completely
electronic
in
opera-
tion
.
Air
flow
is
measured
electronically
via
a
mass
air
flow
sensor
and
additional
sensors
supply
information
about
en-
gine
operating
conditions
.
The
ECM
calculates
the
amount
of
fuel
needed
for
the
correct
air-fuel
ratio
and
actuates
the
fuel
injectors
accordingly
.
The
amount
offuel
metered
to
theen-
gine
is
determined
by
how
long
the
injectors
are
open
.
Airintake
.
Air
entering
the
engine
passes
through
a
pleat-
ed
paper
air
filter
in
the
air
cleaner
.
Intake
air
volume
or
mass
is
then
measured
bya
mass
air
flow
(MAF)
sensor
.
In
al¡
ex-
cept
the
vane
type
sensor
(DME
M1
.7),
a
reference
current
is
used
to
heat
a
thin
wireor
film
in
the
sensor
when
the
engine
is
running
.
The
current
used
to
heat
the
wire/film
is
electroni-
cally
converted
into
a
voltage
measurement
corresponding
to
the
mass
of
the
intake
air
.
Table
b
.
Mass
Air
Flow
Sensor
Variants
System
Al
r
flow
sensor
type
Bosch
DME
M1
.7
Vane
(volume
sensor)
Bosch
DME
M3
.1
Hot
wire
(mass
sensor)
Bosch
DME
M3
.3
.1
Hot
film
(mass
sensor)
Bosch
DME
M5
.2
Hot
film
(mass
sensor)
Siemens
MS
41
.1
Hot
film
(mass
sensor)
"
The
16-pin
OBD
11
diagnostic
connector
is
located
on
NOTE-
the
lower
left
dashpanel
.
See
Fig
.
1
.
On
cars
equipped
wíth
tractioncontrol,
an
additional
throttle
valve
is
controlled
by
an
electronic
throttle
actu-
ator
(motor)
.
This
valve
is
used
for
engine
speed
inter
vention
.
Repair
information
forthis
system
is
notcovered
here
due
to
the
special
electrical
testing
equip-
ment
required
to
service
it
.

ELECTRICAL
CHECKS
AND
COMPONENT
TESTING
Main
relay,
testing
The
main
relay
is
energized
via
the
engine
control
module
and
supplies
plus
(+)
power
to
the
many
of
the
engine
man-
agement
components
and
subsystems,
including
the
fuel
pump
relay
.
If
this
relay
is
faulty,
the
engine
will
not
start
.
1
.
With
ignition
off,
remove
main
relay
.
See
Fig
.
6
.
.
iommooommmoi
~
"""
Fuel
DME
sensor
CA
UTION-
Relay
positions
can
vary
.
Be
sure
to
confirm
relay
position
by
identífyíng
the
wiring
in
the
socket
us-
ingthe
wiring
diagramsfound
at
the
rearof
this
manual
.
0013034)
Fuel
pump
relay,
testing
FUEL
INJECTION
130-
7
87
851186
30
~j
1
.
Remove
fuel
pump
relay
from
its
socket
.
87661
Fig
.
7
.
Check
for
battery
voltage
at
main
relay
terminals
30
and
86
.
Voltage
should
be
present
at
all
times
.
4
.
With
ignition
on
and
relay
installed,
check
for
battery
voltage
at
terminals
87
.
"
If
battery
voltage
is
present,relay
has
energized
and
is
functioningcorrectly
.
"
lf
battery
voltage
is
not
present
and
al¡
earlier
tests
are
OK,
relay
is
faulty
and
should
be
replaced
.
Fig
.
6
.
Engine
management
relays
in
the
power
distribution
box,
left
rear
of
engine
compartment
.
The
fuel
pump
relay
is
located
in
the
power
distribution
box
.
Refer
to
Fig
.
6
.
The
ECM
supplies
power
to
the
coil
side
of
the
fuel
pump
re-
lay
.
During
starting,
the
fuel
pump
runs
as
long
as
the
ignition
switch
isin
the
start
position
and
continues
to
run
once
theen-
gine
starts
.
If
the
relay
ís
faulty
the
fuel
pump
will
notrun
.
2
.
Check
for
voltage
at
terminal
30
and
terminal
86
of
re-
¡ay
socket
.
See
Fig
.
7
.
2
.
With
key
off,
check
for
batteryvoltage
at
socket
terminal
"
If
battery
voltage
is
present
continue
testing
30
.
See
Fig
.
8
.
"
lf
battery
voltage
is
not
present
at
either
point,
check
large
red
wire
in
relay
socket
.
See
Electrical
Wiring
3
.
With
ignition
key
in
start
position
check
for
battery
volt-
Diagrams
.
age
at
terminal
86
.
NOTE-
4
.
With
ignition
key,
use
digital
multimeter
to
check
for
The
wiring
to
terminals
85
and
86
in
the
main
relay
may
ground
at
terminal
85
.
be
reversed
.
Electrically,
the
relay
functions
either
way
.
lf
voltage
ís
not
present
at
terminal
86,
check
for
volt-
NOTE-
age
at
terminal
85
.
The
ground
atterminal
85
is
switched
by
the
ECM
.
The
ECM
hamess
must
be
connected
to
check
the
3
.
Reinstall
relay
and
turn
ignition
on
.
Gainaccess
to
un-
switched
ground
connection
.
derside
of
relay
socket
and
check
for
ground
at
terminal
85
(brown
wire)
.
5
.
If
no
faults
are
found
up
tothis
point,
testfuel
pump
op-
"
lf
ground
is
present
continue
testing
.
eration
as
described
in
160
Fuel
Tank
and
Fuel
Pump
.
"
If
ground
is
not
present,
signal
from
ECM
is
missing
.
Check
wire
between
ECM
and
relay
.
If
no
faults
can
be
found,
ECM
may
be
faulty
.
ELECTRICAL
CHECKS
AND
COMPONENT
TESTING

130-
8
FUEL
INJECTION
Fig
.
8
.
Fuel
pump
relayterminal
identification
.
1.
Peel
back
rubber
boot
on
oxygen
sensor
electrical
har-
ness
connector
(car
wiring
side)
.
With
connector
at-
Oxygen
sensor,
testing
tached
to
sensor,
connect
digital
voltmeter
to
pins
1
(BOSch
systems
only)
and
2
in
rear
of
connector
.
See
Fig
.
10
.
CAUTION-
"
The
information
inthis
sectionapplies
to
Bosch
engine
management
systems
only
.
"
The
Siemens
MS
41
.1
system
uses
resistive-type
oxygen
sensors
.
This
sensor
uses
a
5-volt
refer-
ence
signal
input
and
the
output
to
the
ECM
var-
ees
from
1-5
volts,
in
stepped
increments
based
on
oxygen
content
in
the
exhaust
.
NOTE-
"
On
pre-08D
11(1992-1995)
cars,
there
is
one
oxygen
sensor
mounted
upstream
of
the
catalytic
convert-
er(s)
in
the
exhaust
pipe
.
See
Fig
.
9
.
"
On
OBD
11
cars
(1996-1998)
cars,
there
is
one
oxygen
sensor
before
andone
after
each
catalytic
converter
.
"
OnM52
and
S52US
engines,
the
front
pairof
oxygen
sensors
are
installed
in
the
exhaust
manifolds
.
The
oxygen
sensor
providesan
input
voltage
signal
(0-1
VDC)
to
the
ECM
based
on
the
oxygen
content
in
the
exhaust
gas
.
TO
generate
voltage,
the
sensor
temperature
must
exceed
575°F
(300°C)
.
Therefore
it
ís
electrically
heated
.
NOTE-
"
The
test
given
below
is
not
a
conclusive
test
of
oxygen
sensor
efficiency
and
does
not
test
how
quickly
the
oxygensensor
can
react
to
changing
conditions
.
"
Pin
numbers
and
wirecolors
can
vary
.
Always
check
the
wiring
diagrams
to
conflrm
wire
color
and
pinas-
signment
.
ELECTRICAL
CHECKS
AND
COMPONENT
TESTING
0013135
Fig
.
9
.
Oxygen
sensor
location
(arrow)
ahead
of
catalytic
converter
.
3181
model
with
M42
engine
shown
.
1
.
Black
(ground)
2
.
Grey
(signal)
4
.
White
(heater
circuit)
3
.
White
(heater
circuit)
0013189
Fig
.
10
.
Oxygen
sensor
connector
terminal
identification
(sensor
sede)
.
Terminals
numbers
are
molded
into
connector
.
2
.
Start
engine
.
Oxygen
sensorshould
start
to
output
a
fluctuating
voltage
within
a
short
period
.
If
voltage
is
in-
correct,
turn
engine
off
and
check
preheater
circuit
as
described
below
.
WARNING
-
Exhaust
manifolds
and
pipes
can
be
hot
enough
to
cause
serious
burns
.
Wear
suitable
heavy
gloves
and
other
appropriate
protection
.