battery terminals BMW 328i 1997 E36 User Guide

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

Oxygen
Sensor
FUEL
DELIVERY
TESTS
FUEL
INJECTION



130-
9

"
Voltage
at
¡dle
..
.
..
..
....
0
.2
to
0
.8
VDC,
fluctuating



Checking
fuel
delivery
is
afundamental
part
of
trouble-
shooting
and
diagnosing
the
engine
management
system
.
Fuel
pressure
directly
influences
fuel
delivery
.
An
accurate

NOTE-



fuel
pressure
gauge
will
be
needed
to
make
the
tests
.

To
check
sensorresponse
to
lean
and
rich
mixtures,
createenairleak,
orpull
vacuumhoseofffue¡
pressure



There
are
three
significant
fuel
delivery
values
to
be
mea-

regulator
to
increase
fuel
pressure
.



sured
:

3
.
Separate
sensorharness
connector
from
sensor
.
Check

for
battery
voltage
between
terminals
3
and
4
(green

wire
and
brown
wire)
in
main
wiring
harness
side
of
con-

nector
with
engine
running
.
If
voltage
is
not
present,

check
oxygen
sensor
heater
relay
.
See610
Electrical

Component
Locations
.

4
.
Check
heater
element
resistance
between
terminals
3
and
4
in
sensor
side
of
connector
.
If
element
is
electri-

cally
open
(no
continuity),
replace
sensor
.

NOTE-

The
oxygen
sensor
heater
relay
is
mounted
in
the
main
power
distributfon
box
in
the
left
rear
of
the
engine
com-
partment
.
Refer
to
Fig
.
6
.
The
heater
relay
is
energized
wíth
positive
(+)
battery
voltage
from
the
main
relayanda
switched
ground
from
the
ECM
.
See
Electrical
Wir-
ing
Diagrams
.

"
Oxygen
sensor
to
exhaust
pipe
...
..
55
Nm
(41
ft-Ib)

"
System
pressure-created
by
the
fuel
pump
and
main-
tained
by
the
pressure
regulator
.

"
Fuel
delivery
volume-created
by
the
fuel
pump
and
af-
fected
by
restrictions,
suchasclogged
fuel
filter
.

"
Residual
pressure-the
pressure
maintained
in
the
closed
system
after
the
engine
and
fuel
pump
are
shut

off
.

Procedures
for
measuring
the
first
two
quantities
arede-
scribed
in
160
Fuel
Tank
and
Fuel
Pump
.
Residual
fuel
pres-
sure
is
checked
using
the
procedure
detailed
later
in
this

group
.

Operating
fuel
pump
fortests

To
operate
the
fuel
pump
for
testing
purposes
without
hav-

íng
to
runthe
engine,
the
fuel
pump
relay
can
be
bypassed
to

power
the
pump
directly
.
Fuel
pump
relay
location
is
shown
in

Fig
.
6
.

5
.
¡f
oxygen
sensor
doesn't
produce
a
fluctuating
voltage



To
runthe
fuel
pump,
remove
the
fuel
pump
relay
and
con-
and
preheater
circuit
is
OK,
replace
sensor
.



nect
the
socket
for
relayterminal
30
to
the
socket
for
relay
ter-

mina¡
87
with
a
fused
jumper
wire
.
After
completing
the
tests,

NOTE-



remove
the
jumper
wire
.

If
not
already
applied,
coat
the
oxygen
sensor
threads
with
an
anti-seize
compound
before
installation
.
Do
not



CAUTION-
getthe
compound
on
the
sensor
tip
.
"
Relay
locations
may
vary
.
Use
care
when
identi-
fying
relays
and
making
electrical
checks
at
the
fuselrelay
panel
.
See
610
Electrical
Compo

Tightening
Torque



nent
Locations
for
additional
relay
information
.

"
The
fuel
pump
relay
has
a
1
.5
mm2
red
wire
at
ter-
minal
30
in
the
relay
socket
.
Terminal
87
has
a
1
.5
mm
2
greenlviolet
wire
.
See
Electrical
Wiring
Di-
agrams
for
additional
wiring
information
.

NOTE-

Thejumper
wire
should
be
1.5
mm2
(14
ga
.)
and
in-
clude
an
in-line
tuse
holder
with
a15
amp
tuse
.
To
avoid
fuselrelay
panel
damage
from
repeated
connect-
ing
and
disconnecting,
also
include
a
toggle
switch
.
A
heavy-duty
jumper,
BMW
tool
no
.
61
3
050,
is
also
available
from
an
authorized
BMW
dealer
.

FUEL
DELIVERYTESTS

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

130-18



FUEL
INJECTION
The
engine
coolant
temperature
(ECT)
sensor
sends
con-

tinuous
engine
coolant
temperature
information
to
the
ECM
.
Fig
.
26
.
Mass
air
flow
sensor
terminalidentifcation
on
carswith
DME



As
temperature
increases
sensor
resistance
decreases
.
M3
.1
fuel
injection
.

Mass
air
flow
sensor
(hot
film),

testing
and
replacing

MOTE-

A
burn-off
cycle
is
not
used
on
hot
film
sensors
.

8
.
With
ignition
off,
disconnect
harness
connector
from
air



ECT
Sensor
Location
flow
sensor
.
Using
a
digital
multimeter,
check
resis-



"
M50/S50US
engine
............
left
side
of
cylinder
tance
at
terminals
listed
.



head
under
intake
manifold

Air
Flow
Sensor
Test
Values
(DMEM3
.1)

"
Terminals
5
and
6
.
.
.
.........
..
.
..
....
3-4
ohms

If
any
faults
are
found,
check
wiring
lo
and
from
the
ECM
.
Make
ECM
pinout
test
as
listed
in
See
Table
i
.
Main
power
to
air
flow
sensor
comes
from
DME
main
relay
.

On
cars
with
DME
M3
.3
.1
a
hot
film
mass
air
flow
sensor
is
used
.
When
the
engine
is
running,
a
current
is
used
lo
heat
a
thinfilm
in
the
center
of
the
sensor
.
This
current
is
electroni-
cally
converted
into
a
voltage
measurement
corresponding
to
the
mass
of
intake
air
.

If
thehot
film
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
senricedor
adjusted
.

CA
UTION-

Use
only
a
digital
multimeter
when
checking
the
mass
air
flow
sensor
.
An
analogmetercan
dam-
age
the
air
flow
sensor
.

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

1
.
Disconnect
harnessconnector
from
air
flow
sensor
.

2
.
Turn
ignition
on
and
check
for
voltage
and
ground
at

connector
.
There
should
beground
at
pin
1
.
There

should
be
positive
(+)
battery
voltage
at
pin
3
.
If
any
faults
are
found,
check
wiring
to
and
from
ECM
.
Make
ECM
pinout
test
.
See
Table
j
.

NOTE-

Positive
(+)
battery
voltage
to
air
flow
sensor
comes
from
DME
main
relay
when
the
ignition
is
switch
on
orengine
running
.

Engine
coolant
temperature
(ECT)
sensor,

testing
and
replacing

0012704
Fig
.
27
.
Engine
coolant
temperature
(ECT)
sensor
(A)
is
located
be-
neath
top
engine
cover
(B)
and
crankcase
vent
hose
(C)
.
M52
engine
shown
.
M50
is
similar
.

1
.
Check
ECM
reference
voltage
to
sensor
:
"
Disconnect
harnessconnector
from
ECT
sensor
.
"
Turn
ignition
keyon
.
"
Check
for
5
volts
between
supply
voltage
wire
(brown/red)
wire
of
harness
connector
and
ground
.
"
Turn
ignition
key
off
.
"
If
voltage
is'
not
present
or
incorrect,
check
wiring
from
ECM
and
check
referencevoltage
output
at
ECM
(pin
78)
.
See
Table
i
(DM
E
3
.1)
or
Table
j
(DME
3
.3
.1)

2
.
Check
ECT
sensor
resistance
:

"
With
harnessconnector
disconnected,
check
resis-
tance
acrosssensor
terminals
.
"
Compare
tests
results
to
values
in
Table
f
.

130-20



FUEL
INJECTION

Fig
.
29
.
Throttleposition
sensor
terminal
identification
on
M50
engine
.

Tableg
.
Throttle
Position
Sensor
Tests

(DME3
.113
.3
.1)

Test
conditions



I
Terminals



I
Testvalue

Harness
connector



13
andground



15
VDC
(approx
.)
disconnected,
igni-



in
harness
tion
on



connector

Harness
connector



1
and3
at
sen-
14
k
ohms
(approx
.)
disconnected,
igni-



sor
terminals
tion
off

Throttle
plate
rotat-



1
and
2
at
sen-



Variable
from
1
-
4ked
from
¡dieto
full



sor
terminals



ohms
(approx
.)
with-
throttle
position



out
interruption



¡die
Speed
Control
Valve
Coil
Resistance
Values

"
M50/S50US
engine

NOTE-



Terminals
1
and
2
..
.
................
20
t
5
ohms

On
cars
with
tractioncontrol,
do
not
confuse
the
throttle



Terminals
2
and
3
...................
20
t5
ohms
position
sensor
on
the
main
throttle
body
with
the
throt-



Terminals
1
and
3
..
.
..
:
............
.40
t
5
ohms
tle
positionswitch
on
the
secondary
throttle
body,
where
applicable
.

¡die
speed
control
valve,
testing

¡die
speed
is
maintained
by
the
ECM
through
the
¡die
speed
control
valve
.
The
¡die
controlfunction
compensates
for
engine
load
and
engine
operating
conditions
.
¡die
speed
is
adaptive
through
the
ECM
and
no
¡die
speed
adjustments
can
be
made
.

NOTE-
Before
testing
the
valve,
confirm
that
the
throttle
position



The
idle
speed
controlvalve
receives
positive
(+)
bat-
sensor
is
working
correctly
.



tery
voltage
from
the
main
relay
.

BOSCH
DME
M3
.
1
AND
M3
.3
.1
COMPONENT
TESTS
AND
REPAIRS

NOTE-

"
The
tests
given
below
are
electrical
checks
only
.
They

do
not
check
the
mechanical
operation
of
the
valve
.
If
the
valve
is
suspected
of
causing
poor
idie,
substitut-
ing
a
known
good
valve
is
the
best
way
to
check
for
a
mechanical
fault
.

1
.
With
engine
running,
check
that
¡die
speed
control

valve
is
buzzing
.

2
.
Turn
on
A/C
or
shift
car
finto
drive
.
¡die
should
remain
steady
orincrease
slightly
.

3
.
If
valve
is
not
buzzing,or
if
¡die
decreases
in
step
2,

stop
engine
and
disconnect
harness
connector
from
valve
.
Check
resistance
of
valve
across
its
terminals
.

See
Fig
.
30
.
Test
values
are
listed
below
.

NOTE
-

If
you
suspect
an
intermittent
fault,
lightly
tapthe
valve
while
testing
resistance
.

11250

Fig
.
30
.
¡die
speed
control
valve
terminal
identification
.

4
.
With
valve
harnessconnector
disconnected,
check
for
battery
voltage
at
red/white
wire
in
connector
with
igni-

tion
tumed
on
.

"
If
there
is
no
voltage,
check
wiring
between
connec-
tor
and
main
relayterminal
87
.
See
Electrical
Wiring
Diagrams
.

5
.
If
voltage
is
presentas
described
above,
check
wiring
between
ECM
and
valve
.
If
no
wiring
faults
are
found,
check
ECM
signal
to
valve
.

Fuel
leve¡
senders,
testing



Fuel
leve¡
sender
(right
side)

The
left
and
right
fuelleve¡
sending
units
are
wired
in
series
.



and
fuel
pump,
removing
and
installing

The
fuel
gauge
receives
a
signal
that
is
the
average
of
the
two



1
.
Disconnect
negative
(-)
cable
from
battery
.

input
values
.

1
.
Remove
rear
seat
cushion,
lift
up
insulation
mats,
andremove
both
fuel
tank
access
covers
.

2
.
Disconnect
white
plug
on
each
sending
unit
.
See
Fig
.
6
.

3
.
Check
resistance
value
of
eachsending
unit
.
Values
should
be
the
same
.

5
.
If
valuesare
different,
remove
sending
units
as
described

below,
and
check
resistance
valuésacross
terminals
.
Table
a

lists
resistance
values
for
senders
at
various
float
positions
.

Table
a
.
Fuel
Leve¡
Sender
Resistances

Float
position



Test
result
(ohms)

Right
side
empty



10
ohm
t2

Right
side
full



250
ohm
±
5
Left
side
empty



10
ohm
t
2

Left
side
fui¡



250
ohm
±
5

FUEL
TANK
AND
FUEL
PUMP



160-
5

CAUTION
-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautionsglven
at
the
front
of
this
manual
onpage
viii
.

2
.
Drain
fuel
from
tank
as
described
earlier
.

WARNING
-

Always
unscrew
the
fuel
tank
cap
to
release
pres-
sure
in
the
tank
before
working
on
the
tank
or
fines
.

3
.
Remove
rear
seat
cushion
and
pull
back
insulation
pad
under
right
side
.

4
.
Remove
screws
holding
rightfuel
tank
accesscover
.

Remove
cover
.

5
.
Label
fuel
hoses
.
Disconnect
hoses
and
harness
con-

nectors
from
fuel
sending
unit
and
fuel
pump
.

6
.
Unscrew
threaded
collar
from
fuel
pumplfuel
leve¡
sender
.
Slowly
withdraw
assembly
from
tank,allowing

fuelto
drain
off
.
See
Fig
.
7
.
0013187
&
0013194

Fig
.
6
.



Fuel
pump/leve¡
sender
terminal
identification
.
Check
resis-
tance
at
terminals
of
white
connectors
(arrows)
.



"
If
necessary,
push
leve¡
sender
arm
toward
fuel
pump

assembly
to
facilitate
removal
.

NOTE
-

BMW
special
tool
no
.
16
1
020
should
beused
to
re-
move
and
install
the
threaded
collar
.
Damage
to
the
collar
may
result
if
the
special
tool
is
not
used

WARNING
-

NOTE-



Fuel
may
be
spilled
.
Do
not
smoke
or
work
near

The
compensating
siphon
pump
(Fig
.
1)
maintains
the



heaters
or
other
fire
hazards
.

fuel
leve¡
between
the
right
and
left
tank
lobes
.
If
the
re-
sistances
are
different
between
the
left
and
right
send-
ers,
remove
the
senders
and
visually
inspect
the
leve)
in



7
.
Using
a
new
sealing
ring,
install
pump
and
sending
each
lobe
.
If
the
leve¡
is
different,
check
the
siphon
com-



unit,
being
sure
that
fuel
line
connections
point
in
same

pensating
pump
.



direction
as
they
carne
out
.

8
.
Reconnect
harnessconnector
and
hoses
.
Fill
tank
and

check
for
leaks
by
running
engine
.
Insta¡¡
access
cover

and
its
mountingscrews
.
Reconnect
negative
(-)
cable

to
battery
.

CAUTION
-

Before
starting
the
engine,
fill
the
fuel
tank
with
at
least
1
.5
gallons
(5liters)
of
fuel
.
The
pump
will
be
damaged
if
you
run
it
without
fuel
.

FUEL
LEVEL
SENDERS

Fig
.
9
.



Fuel
pump
relay
terminal
identification
.

Fuel
Pump
Electrical
Tests

Troubleshooting
of
any
fuel
pump
fault
should
begin
with

checking
the
fuel
pump
fuse
and
the
fuel
pump
relay
.
The
DME
main
relay
should
also
be
checked
.

NOTE-

Special
tools
are
requíred
for
some
of
the
tests
de-
scribed
here
.

Fuel
pump
electrical
circuit,
testing

The
fuel
pump
electrical
circuit
diagram
is
shown
in
Fig
.
10
.

3
.
If
fuel
pump
does
not
run,
disconnect
black
harness

connector
from
tank
sender
unit
.
With
jumper
wire
con-

nectedas
described
in
step
2
above,
check
for
positive

(+)
batteryvoltage
at
harness
connector
terminals
.
See
Fig
.
11
.

FUEL
TANK
AND
FUEL
PUMP



160-
7

From
Main
Relay
(+15
power
with
key
in
run



From
B+juretion
point
orstartposition)
(batteryvoRageatalltirnes)

'
.5
RD/Nrr



1
.5
RD

1
.5
GNNI

From
Engine



2
.5
GNNI
Control
Module



15
2
.5
GNNI

Ground
(below
center
console)

Fig
.
10
.
Fuel
pump
electrical
circuit
.

30

-~
Relay
Fuel
Pump

8~T

I



1

s
ám
61
Front
Power
I



a
1
Distribution
Box
I_
16

WIRING
COLOR
CODE

BK
-
BLACK
BR
-
BROWN
Fuel
Pump



RD



-



RED
(in-tank)
M
YL
YELLOWGN
-
GREENBU
-
BLUE
1
VI
-
VIOLET
GY
-
GREY
WT
-
WHITE
PK
-
PINK

0011946

4
.
If
voltage
and
groundare
present,
fuel
pump
is
proba-
bly
faulty
.
If
there
is
no
voltage,
check
wiring
From
fuel
pump
Reay
and
make
sure
Reay
is
functioning
correctly
.

CAUTION-

Fuseandrelaylocationsmayvary
.
Usecara
when



Fuel
pump
power
consumption,
testing

troubleshooting
the
electrical
system
at
the
fuselrelay
panel
.
To
resolve
problems
in
identify-



NOTE-
ing
a
relay,
see
en
authorízed
BMW
dealer
.



"
To
achieveaccurate
testresults,
fhe
battery
voltage
at
the
connector
should
be
approximately
13
volts
.
1.
Remove
rearseat
cushion,
pull
right
side
insulation
mat



Charge
the
battery
asnecessary
.

back
to
expose
fuel
tank
accesscover
.
Remove
cover



.
q
higher
than
normal
power
consumption
usually
fin-
to
expose
wiring
connections
.



dicates
a
worn
fuel
pump,
which
may
cause
intermit-
tentfuel
starvation
due
lo
pump
overheating
and
2
.
Remove
fuel
pump
relay
and
opérate
fuel
pump
as
de-



seizure
.
The
only
remedy
is
pump
replacement
.
Be
scribed
under
Operating
fuel
pump
for
tests
earlier
.



sure
to
check
that
thereturn
fine
and
the
pump
pickup
Pump
should
run
.
Disconnect
jumper
wire
when
fin-



are
not
obstructed
before
replacing
the
pump
.

ished
.
1
.
Remove
rear
seat
cushion,
pull
right
side
insulation
mal
back
to
expose
fuel
tank
accesscover
.
Remove
cover
to
expose
wiring
connections
.

2
.
Disconnect
(black)
harness
connector
from
fuel
pump
.

3
.
Connect
an
ammeter
and
an
insulated
jumper
wire
be-

tween
terminals
in
connector
and
corresponding
pump

terminals
.
See
Fig
.
12
.

FUEL
PUMP

600-2



ELECTRICAL
SYSTEM-GENERAL

CAUTION
-

"
Always
turn
off
the
engine
and
disconnect
the

negative
()
cable
from
the
batterybefore
remov-

ing
any
electrical
components
.
Disconnecting
the

battery
may
erase
fault
code(s)
stored
in
control

module
memory
.
Check
for
fault
codes
using
spe-
cial
BMW
diagnostic
equipment
.

"
Prior
to
disconnecting
the
battery,
read
the
bat-

tery
disconnection
cautions
given
at
the
front
of

this
manual
onpage
viii
.

"
Connect
and
disconnect
ignition
system
wires,
multiple
connectors,
and
ignition
test
equipment
leads
only
while
the
ignition
is
off
.

"
Do
not
disconnect
the
battery
with
engine
run-

ning
.

"
Do
not
quick-charge
the
battery
(for
boost
start-
ing)
for
longer
than
one
minute,
and
do
not
ex-
ceed
16
.5
volts
at
the
battery
with
the
boosting
cables
attached
.
Wait
at
feast
one
minute
before
boosting
the
battery
a
second
time
.

"
Do
not
usea
test
famp
that
has
a
normal
incan-

descent
bulb
to
test
circuits
contafning
electronic
components
.
The
high
electrical
consumptionof
these
test
lamps
may
damage
the
components
.

"
Do
not
use
an
analog
meter
.
Use
onfy
a
digital
multimeter
.

"
Many
of
the
solid-state
modules
are
static
sensi-
tive
.
Static
discharge
will
permanently
damage
them
.
Always
handle
the
modules
using
proper
static
prevention
equipment
and
techniques
.

"
To
avoid
damaging
harness
connectors
or
relay
panel
sockets,
use
jumper
wires
with
flat-blade
connectors
that
are
the
same
size
as
the
connec-
tor
or
relay
terminals
.

"
Always
switch
a
digital
multimeter
to
the
appropri-
ate
function
and
range
before
making
test
con-
nections
.

"
Do
not
tryto
start
the
engine
of
a
carwhich
has
been
heated
above176°F
(80°C),
(for
example,
in
a
paint
dryingbooth)
.
Allow
it
to
cool
to
normal
temperature
.

"
Disconnect
the
battery
before
dolng
any
electric
welding
on
the
car
.

"
Do
not
wash
the
engine
while
it
is
runnfng,
or
any-
time
the
ignition
is
switched
on
.

WIRING
DIAGRAMS

Electrical
Test
Equipment

Many
of
the
electrical
tests
described
in
this
manual
call
for

measuring
voltage,
currentorresistanceusing
a
digital
multi-

meter
(DMM)
.
Digital
meters
are
preferred
for
precise
mea-

surements
and
for
electronics
work
because
they
are
generally
more
accuratethan
analog
meters
.
The
numerical

display
is
alsoless
likely
to
be
misread,
since
there
is
no
nee-

dle
position
to
be
misinterpreted
by
reading
at
an
angle
.

An
LED
test
light
is
a
safe,
inexpensive
tool
that
can
be
used

to
perform
many
simple
electrical
tests
that
would
otherwise

require
a
digital
multimeter
.
The
LED
indicates
when
voltage

is
present
between
anytwo
test-points
in
a
circuit
.

CA
UTION-

"
Choose
test
equipment
carefully
.
Use
a
digital

multimeter
with
at
leadt
10
megaohm
input
im-

pedance,or
an
LED
test
light
.
An
analog
meter
(swing-need1e)
ora
test
light
with
a
normal
incan-
descent
bulb
may
draw
enough
current
to
dam-
age
sensitive
electronic
components
.

"
An
ohmmeter
must
not
beused
to
measure
resis-
tance
on
solidstate
components
suchas
controlunits
or
time
delay
relays
.

"
Always
disconnect
the
battery
before
making
re-

sístance
(ohm)
measurements
on
the
circuit
.

WIRING
DIAGRAMS

The
wiring
diagrams
shown
in
Electrical
Wiring
Diagrams

have
been
specially
designed
to
enable
quick
and
efficientdi-

agnosis
and
troubleshooting
of
electrical
malfunctions
.

Wiring
Codes
and
Abbreviations

A
lot
of
information
is
included
in
each
wiring
diagram
if
you
know
how
to
read
them
.
Wire
colors
in
the
diagrams
are
ab-

breviated
.
Combined
color
codes
indicate
a
multi-colored
wire
.
For
example
the
code
BLU/RED
indicates
a
Blue
wire

with
a
Red
stripe
.

Many
electrical
components,
connectors,
fuses,
and

ground
locations
are
identified
using
a
unique
number
.
Each

of
there
numbers
corresponds
to
a
particular
part
in
the
circuit
commonly
found
in
Electrical
Wiring
Diagrams
.