120-10
IGNITION
SYSTEM
Ground
(rear
of
engine
compartment,
rear
of
passenger
side
shock
tower)
.!
BK
Camshaft
Position
Sensor
IGNITION
SYSTEM
SCHEMATICS
Batteryvoltage
in
run
or
start
(
via
ignition
switch
terminal
15)
---------------------------------------------------------
55
S5154
i
power
input
Power
input
1
DME
Control
Module(Bosch
DME
M3
.1)
Ground
-
(RHrear
of
enginecompartment,
rearof
passenger
side
shock
tower)
Fig
.
15
.
Bosch
DME
M3
.1
usedon1992
M50
engines(without
VANOS)
.
.EBK
Crankshaftlrpm
Position
Sensor
5GN
1.0
RD
Ground
(RH
rearof
enginecompartment,
rear
of
passenger
side
shock
tower)
WIRING
COLOR
CODE
BK
-
BLACK
BR
-
BROWN
RD
-
RED
YL
-
YELLOWGN
-
GREEN
BL
-
BLUE
VI-
VIOLET
GY
"
GREY
WT
"
WHITE
PK
-
PINK
Batteryvoltage
in
run
or
start
(
via
main
relay
Battery
voltage
terminal
87)
in
run
or
start
(via
ignition
switch
terminal
15)
11508
1
grounds
Main
rela
control
P
ower
Input
Y
I
-
34
---"--
6
26
27
1
Battery
voltage
at
all
times
to
Main
relay
(terminal
85)
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
121-2
BATTERY,
STARTER,
ALTERNATOR
CHARGING
SYSTEM
TROUBLESHOOTING
Static
currentdraw,
checking
Charging
system
diagnostics
requires
special
test
equip-
ment
.
If
the
test
equipment
is
not
available,
charging
system
fault
diagnosis
can
be
performedby
an
authorized
BMW
deal-
eror
other
qualified
repair
shop
.
A
general
troubleshooting
guide
is
given
in
Table
a
.
Charging
System
Quick-Check
As
a
quick-check,
use
a
digital
multimeter
lo
measure
volt-
2
.
Disconnect
battery
negative
(-)
cable
.
age
across
the
battery
terminals
with
the
key
off
and
then
again
with
the
engine
running
.
The
battery
voltage
should
be
CAUTION-
about12
.6
volts
with
key
off
and
approximately
14
.0
volts
with
Prior
to
disconnecting
the
battery,
read
the
battery
the
engine
running
.
If
the
voltage
does
not
increase
when
the
disconnection
cautions
given
at
the
front
of
this
engine
is
running,there
is
a
fault
in
the
charging
system
.
manual
onpaga
viii
.
NOTE
-
The
regulated
voltage
(engine
running)
should
be
be-
tween
13
.5
and
14
.5,
depending
on
temperatura
and
operating
conditions
.
If
the
voltage
is
higher
than
14
.8,
the
voltage
regulator
is
most
Mely
faulty
.
Check
for
clean
and
tight
battery
cables
.
Check
the
ground
cable
running
from
the
negative
(-)
battery
terminal
lo
the
chassis
and
the
ground
cable
running
from
the
engine
lo
the
chassis
.
Check
the
alternator
drive
belt
condition
and
tension
.
If
the
battery
discharges
over
time,
there
may
be
a
constant
drain
or
current
draw
on
the
battery
.
A
small
static
drain
on
the
battery
is
normal,
but
a
largedrain
will
cause
the
battery
lo
quickly
discharge
.
Make
a
static
current
draw
test
asthe
first
step
when
experiencing
battery
discharge
.
1
.
Make
sure
ignition
and
al¡
electrical
accessories
are
switched
off
.
3
.
Connect
a
digital
ammeter
between
negative
battery
post
and
negative
battery
cable
lo
measure
current
.
See
Fig
.
1
.
Wait
at
least
one
minuta
lo
get
an
accurate
reading
.
A
range
of
about
0
lo
100
milliamps
is
normal,
dependingon
the
number
of
accessories
that
need
constant
power
.
A
current
of
400
milliamps
(0.4
amp)
or
more
may
indicate
a
problem
.
Table
a
.
Battery,
Starter
and
Charging
System
Troubleshooting
Symptom
1
Probable
Cause
1
Correctiva
Action
1
.
Engine
cranks
slowlyor
not
a
.
Battery
cables
loose,
dirty
orcor-
a
.
Clean
or
replace
cables
.
See020
Maintenance
Program
.
a
tall,
solenoíd
clicks
when
roded
.
starter
is
operated
.
b
.
Battery
discharged
.
b
.
Charge
battery,
test
and
replace
if
necessary
.
c
.
Body
ground
straploose,
dirty
or
c
.
Inspect
ground
strap,
clean,
tighten
or
replace
if
necessary
.
corroded
.
d
.
Poor
connection
at
starter
motor
d
.
Check
connections,
test
for
voltage
at
starter
.
Test
for
voltage
at
terminal
30
.
neutral
safety
or
clutch
interlock
switch
.
e
.
Starter
motor
or
solenoid
faulty
.
e
.
Test
starter
.
2
.
Battery
will
not
stay
a
.
Short
circuit
draining
the
battery
.
a
.
Test
for
excessive
current
drainwith
everything
electrical
in
the
charged
more
than
a
few
vehicle
off
.
days
.
b
.
Short
driving
trips
and
high
elec-
b
.
Evaluate
driving
style
.
Where
possible,
reduce
electrical
con
trical
drain
on
charging
system
sumption
when
making
short
trips
.
does
not
allow
battery
to
re-
charge
.
c
.
Drive
belt(s)
worn
or
damaged
.
c
.
Inspect
or
replace
multi-ribbed
belt(s)
.
See
020
Maintenance
Program
.
d
.
Battery
faulty
.
d
.
Test
battery
and
replace
íf
necessary
.
e
.
Battery
cables
loose,
dirty
orcor-
e
.
Clean
or
replace
cables
.
See
020
Maintenance
Program
.
rodad
.
f
.
Alternatoror
voltage
regulator
f
.
Test
alternator
and
voltage
regulator
.
faulty
.
3
.
Battery
losing
water
.
1
a
.
Battery
overcharging
.
1
a
.
Test
voltage
regulator
for
proper
operation
.
4
.
Lights
dim,
light
intensity
a
.
Drive
belt(s)
worn
or
damaged
.
a
.
Inspect
or
replace
multi-ribbed
belt(s)
.
See
020
Maintenance
varies
with
engine
speed
.
Program
.
b
.
Alternatoror
voltage
regulator
b
.
Test
alternator
and
voltage
regulator
.
faulty
.
c
.
Body
ground
straps
loose,
dirty
or
c
.
Inspect
ground
straps,
clean,
tighten
or
replace
as
necessary
.
corroded
.
CHARGING
SYSTEM
TROUBLESHOOTING
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
Alternator
brushes,
STARTER
SERVICE
inspecting
and
replacing
Regulator
brushesarenot
available
as
replacement
parts
from
BMW
.
Replacement
brushes
may
be
available
from
af-
termarket
sources,
however
.
1
.
Remove
voltage
regulator
as
described
above
.
2
.
Clean
brush
contact
sürfaces
and
measure
brush
pro-trusion
.
See
Fig
.
7
.
Check
for
battery
voltage
at
terminal
50
of
the
starter
motor
Fig
.
7
.
Regulator
brush
protrusion
(A)
.
with
the
key
in
the
start
position
.
See
Fig
.
8
.
If
voltage
is
not
present,
check
the
wiring
between
the
ignition
switch
and
the
starter
terminal
.
If
voltage
is
present
and
no
other
visible
wir
Voltage
Regulator
ing
faults
can
be
found,
the
problem
is
most
likely
interna¡in
"
Brush
protrusion
(minimum)
.......
.
..
5
mm
(
1
/4
in
.)
the
starter
motor
.
3
.
To
replace
brushes,
carefully
and
as
quickly
as
possi-
ble,
unsolder
brush
lead
from
brush
holder
termina¡,
withdrawing
brush
from
holder
at
same
time
.
4
.
Remove
any
traces
of
solder
frombrush
holder
termi-
nal
using
solder
wick
.
5
.
Fit
spring
into
brush
holder
and
inserí
new
brush
.
6
.
Guide
brush
lead
into
terminal
and
solder
into
place
.
Check
for
free
movement
of
brushes
when
solder
cools
.
7
.
Check
brush
slip
rings
in
alternator
for
wear
.
Lightly
clean
slip
rings
using
fine
abrasive
cloth
.
BATTERY,
STARTER,
ALTERNATOR
121-
7
Starter
Troubleshooting
If
the
starter
tucos
the
engine
slowlyor
fails
to
operate
when
the
ignition
isin
the
start
position,
check
the
battery
first
.
In-
spect
the
starter
wires,
terminals,
and
ground
connections
for
good
contact
.
In
particular,
make
sure
the
ground
connections
between
the
battery,
the
body
and
the
engine
are
completely
clean
and
tight
.
If
no
faults
can
be
found,
the
starter
may
be
faulty
and
should
be
replaced
.
NOTE
-
"
Starting
in1194,
a
factory-installed
drive-away
protec-
tion
system,
alsoreferred
to
as
EWS
or
EWS
11,
was
used
on
all
E36
cars
.
This
system
prevenís
operation
of
the
starter
when
the
system
is
engaged
.
See
515
Central
Locking
and
Anti-theft
.
"
On
cars
with
automatic
transmission,
a
starter
relay
and
a
neutral
safetyswitchare
used
to
present
theen-
ginefrom
starting
in
gear
positions
other
than
park
or
neutral
.
ff
voltage
is
not
present
atterminal
50
with
the
key
in
the
startposition,
check
these
components
To
make
the
most
accurate
check
of
the
battery
cables
and
starterwiring,
make
a
voltage
drop
test
on
the
cables
and
wir-
ing
as
described
in
600
Electrical
System-General
.
Terminal
30
'
\
/
Terminal
30h
0012518
8
.
Reinstall
regulator
and
alternator
.
Fig
.
8
.
Typical
starterwiring
terminal
identification
.
Large
wireat
ter-
minal
30
is
direct
battery
voltage
.
Smaller
wire
at
terminal
50
operates
starter
solenoid
via
ignition
switch
.
STARTER
SERVICE
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
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