ESP BMW 328i 1993 E36 Owner's Guide
[x] Cancel search | Manufacturer: BMW, Model Year: 1993, Model line: 328i, Model: BMW 328i 1993 E36Pages: 759
Page 155 of 759
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
Page 157 of 759
3
.
Observe
fuel
pressure
gauge
after
20
minutes
.
The
pressure
shouldnot
drop
off
more
than
0
.5
bar
from
system
pressure
listed
in
Tablec
.
4
.
When
finished
testing,
disconnect
pressure
gauge
and
reconnect
fuel
line
.
If
the
fuel
system
does
not
maintain
pressure,
check
visual-
¡y
for
leaks
in
fuel
lines
orat
unions
.
Leaks
can
also
be
due
to
a
leaking
injector
or
a
faulty
fuel
pump
check
valve
.
Check
the
pump
check
valve
by
repeating
the
test,
butbefore
turning
the
fuel
pump
off,
pinch
off
theretum
line
at
the
fuel
rail
.
If
the
pressure
is
now
maintained,
the
fault
is
most
likely
the
fuel
pump
check
valva
.
Tabla
c
.
Fuel
Pressure
Specifications
Engine
1
Fuel
pressure
4-cytinder
1
3
.0
t
0
.2
bar
(43
.5
t
2
.9psi)
6-cytinder
M50/S50US
engine
3
.0
t
0
.2
bar
(43
.5
±2
.9psi)
M52/S52US
engine
3
.5
f
0
.2
bar
(51
t
2.9psi)
Fuel
pressure
regulator
response
to
engine
load,
testing
1
.
With
fuel
pressure
gauge
connected,
reinstallfuel
pump
relay
.
Start
engine
and
allow
it
to
idle
.
NOTE-
The
fuel
pressure
should
be
lower
by0
.4-0.7
bar
from
the
specifications
listed
in
Table
c
.
Engine
vacuum
act-
ing
on
the
fuel
pressure
regulator
diaphragm
reduces
the
fuel
pressure
.
2
.
With
engine
idling,
remove
vacuum
hose
from
regula-
tor
.
Pressure
should
increase
.
3
.
Reconnecthose
and
check
that
pressure
decreases
.
4
.
When
finished
testing,
disconnect
pressure
gauge
and
reconnect
fuelline
.
Tighten
hose
clamp
.
0013190
Fig
.
13
.
For
electrical
tests,
4-cytinder
fuel
injector
harnessduct
can
be
If
fuel
pressure
does
not
drop
with
the
vacuum
hose
con-
accessed
between
intake
manifold
and
cytinder
head
cover
.
nected
and
no
faulty
are
found
with
fuel
the
pressure
regulator
vacuum
hose,
the
fuel
pressure
regulator
is
faulty
.
1
.
Check
that
ECM
signal
is
present
atinjector
connector
.
NOTE-
A
cracked
or
leaktng
pressure-regulator
vacuum
hose
may
cause
en
erratic
tdle
.
FUEL
INJECTION
130-
11
Fuel
rail
and
injectors,
checking
The
fuel
injectors
are
switched
on
and
off
(opened
and
closed)
by
the
ECM
.
The
injectors
are
connected
to
a
com-
mon
fuel
supply,
callad
the
fuel
rail
.
The
fuel
injectors
are
removed
by
first
removing
the
com-
plete
fuel
rail
assembly
and
then
unclipping
the
injectors
from
the
fuel
rail
.
CA
UTION-
Use
only
a
digital
multimeter
or
an
LED
injector
tester
when
testing
injectors
or
wiring
.
Use
of
ananalog
VOM
or
incandescent
testlight
may
dam-
age
the
engine
control
module
.
NOTE-
"
On
4-cytindercars
pry
up
the
injector
wiring
duct
and
then
pry
off
the
cover
.
See
Fig
.
13
.
"
On
6-cytinder
cars
it
is
necessary
to
remove
the
top
engine
cover(s)
to
access
the
fuel
rail
and
injectors
.
"
Back
probe
injector
harness
connector
using
digital
voltmeter
.
See
Fig
.
14
.
"
Operate
starter
or
run
engine
and
check
for
pulsad
voltage
signal
.
"
Repeat
for
each
injector
.
NOTE
-
To
quick-check
if
en
injectorfunctioning,
place
a
screw-
driver
or
stethoscope
on
the
injector
with
the
engine
running
.
If
the
injector
is
operating,there
should
been
audible
buzz
.
FUEL
DELIVERYTESTS
Page 158 of 759
130-
1
2
FUEL
INJECTION
Fig
.
14
.
Voitmeter
connected
across
fuel
injector
connector
with
en-
gine
running
.
M50
engine
shown
.
2
.
If
no
signal
is
present,
check
for
b+
power
to
injectors
.
There
should
be
battery
voltage
(+)
at
red/whitewire
of
each
injector
connector
with
the
ignition
key
on
.
If
volt-
age
is
not
present,
check
main
relay
output
.
Injector
b+
power
comes
from
main
relay
(terminal
87)
.
NOTE-
If
there
is
positive
(+)
batteryvoltage
at
injectors
but
there
was
no
pulsedresponse
at
voltmeter,
check
the
wire(s)
from
the
ECM
to
the
injectors
.
If
no
wiring
faults
can
be
found,
the
pulsed
ground
signal
from
the
control
module
may
be
missing
.
Check
the
outputs
from
the
ECM
.
Fuel
rail
and
injectors,
replacing
1
.
Disconnect
negative
(-)
battery
cable
.
CAUTION-
Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
tront
of
this
manual
on
page
viii
.
2
.
M42
and
M50/S50US
engines
:
Working
at
end
offuel
rail,
disconnect
small
vacuum
hose
from
fuel
pressure
regulator
.
3
.
M50/S50US
engines
:
Remove
two
nuts
from
injector
duct
.
Carefully
pry
injector
wiring
duct
off
ínjectors
.
See
Fig
.
15
.
4
.
On
4-cylinder
cars,
remove
upper
intake
manifold
to
ac-
cess
the
fuel-rail
and
injectors
.
See
113
Cylinder
Head
Removal
and
Installation
.
FUELDELIVERYTESTS
Fig
.
15
.
Injector
wiring
harness
duct
being
removed
from
M50
engine
.
NOTE
-
Late-model
M42
and
all
M44
fuel
injectors
are
afr-
shrouded
.
See
Fig
.
16
.
When
removing
the
fuel
rail
it
is
necessary
to
remove
the
air
shroud
feeder
hose
from
the
intake
manifold
ducting
.
Fig
.
16
.
Cutaway
view
of
fuelinjector
usedon
M42
or
M44
engine
.
5
.
Disconnect
fuel
supply
line
and
fuel
retum
line
from
fuel
rail
ends
.
WARNING
-
"
Clamp
off
the
fuel
lines
and
then
wrapa
clean
shop
towei
around
the
lines
before
removing
them
.
Residual
fuel
pressure
is
present
in
the
lines
.
"
Fuel
will
be
discharged
.
Do
not
disconnect
any
wires
that
could
cause
electrical
sparks
.
Do
not
smoke
or
worknear
heaters
or
other
fire
hazards
.
Keepan
approved
fire
extinguisher
handy
.
Page 161 of 759
u0
I
.[
Ia
Fig
.
21
.
Air
flow
sensor
harness
connector
terminal
identification
.
4
.
Replacing
air
flow
sensor
:
"
Remove
large
band
clamp
attaching
air
boot
to
sensor
.
"
Remove
airfiltertop
cover,
then
remove
airflow
sensor
mounting
nuts
inside
cover
.
"
Reconnect
air
boot
and
harness
connector
.
Engine
coolant
temperature
(ECT)
sensor,
testing
and
replacing
The
engine
coolant
temperature
(ECT)
sensor
sends
con-
tinuous
engine
coolant
temperature
information
to
the
ECM
.
As
temperature
increases,
sensor
resistance
decreases
.
"
With
harness
connector
disconnected,
check
resis-
tance
across
sensor
terminals
.
"
Compare
tests
results
to
values
in
Table
d
.
FUEL
INJECTION
130-
1
5
0011984
Fig
.
22
.
M42
engine
coolant
temperature
(ECG
sensor
(arrow)
.
Table
d
.
Engine
Coolant
Temperature
Sensoror
Intake
Air
TemperatureSensor
Test
Values
(DME
1
.7)
Test
temperatures
Resistance
(k
ohms)
',
14±2°F(-10t1°C)
7-11
.6
68±2°F
(20
t
1
°C)
2
.1
-2
.9
176
±
2°F
(80
t
V
C)
0
.27-0
.40
The
ECT
sensor
is
located
under
number
one
intake
run-
'
ner
.
See
Fig
.
22
.
NOTE-
1
.
Check
ECM
referente
voltage
to
sensor
:
The
test
values
listed
represent
only
three
test
points
from
a
continuous
resistance
NTC
sensor
.
Check
the
"
Disconnect
harness
connectorfrom
ECT
sensor
.
full
linear
response
to
increasing
temperature
as
the
"
Turn
ignition
key
on
.
engine
warms
up
.
"
Check
for
5
volts
between
supply
voltage
(brown/red)
wire
of
harness
connector
and
ground
.
3
.
If
ECT
sensor
fails
these
tests,
it
is
faulty
and
should
be
"
Turn
ignition
key
off
.
replaced
.
If
no
faults
are
found,
reconnect
electrical
"
If
voltage
is
not
present
or
incorrect,
check
wring
from
harness
.
ECM
and
check
ECT
sensor
reference
voltage
output
at
ECM
.
See
Table
h
.
NOTE-
2
.
Check
ECT
sensor
resistance
:
Use
a
new
copper
sealing
washer
when
installing
sen-
sor
.
Reptace
any
lost
coolant
.
WARNING
-
Do
not
replace
the
ECT
sensor
unlessthe
engine
is
cold
.
Hot
coolant
can
scald
.
Tightening
Torque
"
ECT
sensor
to
cylinder
head
.....
..
13
Nm
(10
ft-Ib)
BOSCH
DME
M1
.7
COMPONENT
TESTS
AND
REPAIRS
Page 164 of 759
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
.
Page 165 of 759
Table
f
.
Engine
Coolant
TemperatureSensor
or
Intake
Air
TemperatureSensor
Test
Values
(DME
3
.113
.3
.1)
Test
temperatures
Resistance
(k
ohms)
14±
2°F
(-10
±
1'C)
7-11
.6
68±
2°F
(20
±
1'C)
2
.1
-2
.9
17612°F
(80
t
V
C)
0
.27-0
.40
NOTE
The
test
values
listed
represent
only
three
test
points
from
a
continuous
resistance
NTC
sensor
.
Check
the
full
linear
response
to
increasing
temperatures
as
the
engine
warms
up
.
3
.
If
ECT
sensor
fails
these
tests,
it
is
faulty
and
should
be
replaced
.
If
no
faults
are
found,
reconnect
electrical
harness
.
WARNING
-
Do
not
replace
the
ECT
sensor
unless
the
engine
is
cold
.
Hot
coolant
can
scald
.
NOTE-
Use
"
a
new
copper
sealing
washer
when
installing
sensor
.
Replace
any
lost
coolant
.
Tightening
Torque
"
Engine
coolant
temperature
sensor
to
cylinder
head
.........
..
.
..
...
13
Nm
(10
ft-lb)
Intake
air
temperature
(IAT)
sensor,
testing
and
replacing
The
intake
air
temperature
(IAT)
sensor
signal
is
usedasa
correction
factor
for
fuel
injection
and
ignition
timing
.
Thissen-
sor
is
mounted
in
the
intake
manifold
behind
the
throttle
posi-
tion
switch
.
See
Fig
.
28
.
Check
TPS
function
by
disconnecting
theharnessconnec-
1
.
Check
that
ECM
reference
voltage
is
reaching
IAT
sen-
tor
and
testing
continuity
across
the
terminalswhile
changing
sor
:
the
throttle
position
.
Resistance
test
values
are
listed
below
.
If
"
Disconnect
IAT
sensor
harness
connector
.
the
resuits
are
incorrect,
replace
the
throttle
position
sensor
.
"
Turn
ignition
keyon
.
See
Fig
.
29
.
"
Check
for
5
volts
between
supply
voltage
wire
of
har-
ness
connector
and
ground
.
NOTE-
"
Turn
ignition
key
off
.
The
throttle
position
sensor
is
not
adjustable
.
If
test
re-
sults
are
incorrect,
the
sensor
should
be
replaced
.
IAT
Sensor
Supply
Voltage
"
M50/S50US
engines
.
........
grey
wire
and
ground
FUEL
INJECTION
130-19
Fig
.
28
.
Intake
air
temperature
sensor
location
on
M50/S50US
engine
(arrow)
.
If
voltage
is
not
present
or
incorrect,
check
wiring
from
ECM
and
check
reference
voltage
signal
at
ECM
(pin
77)
.
See
Ta-
ble
i
or
Table
j
.
2
.
Check
IAT
sensor
resistance
:
"
With
harness
connector
disconnected,
check
resis-
tance
acrosssensor
terminals
.
Compare
tests
resuits
to
values
in
Table
f
given
earlier
.
"
If
IAT
sensor
fafs
thistest
it
is
faulty
and
should
be
re-
placed
.
3
.
If
no
faults
are
found,
reconnect
electrical
harness
.
Throttle
position
sensor
(TPS),
testing
and
replacing
The
throttle
position
sensor
(TPS)
is
mounted
on
the
side
of
the
throttle
housing
and
is
directly
connected
to
the
throttle
valve
shaft
.
The
ECM
sends
a
voltage
signal
to
the
potentiom-
eter-type
sensor
and
monitors
the
voltage
that
comes
back
.
BOSCH
DME
M3
.
1
AND
M32
.1
COMPONENT
TESTS
AND
REPAIRS
Page 185 of 759
160
Fuel
Tank
and
Fuel
Pump
GENERAL
.
.
.
.
.
.
...........
.
....
.
.
.
.
.
.
160-1
Operating
fuel
pump
for
tests
.
.
.
.
.
.
.......
.160-6
Fuel
Pump
Electrical
Tests
.
.
.
.
.
.
.
...
.
.
.
.
.
160-7
FUEL
TANK
AND
LINES
..
.
.
.
..........
160-2
Fuel
pump
electrical
circuit,
testing.
...
.
.
.
.
.
160-7
Fuel
tank,
draining
..
.
.
.
.
.
.
.
.
.
..........
160-2
Fuel
pump
power
consumption,
testing
.
.
.
.
.
.
160-7
Fuel
tank,
removing
and
installing
.........
160-3
Fuel
Delivery
Tests
....
.
.
.
...
.
.....
.
.
.
..
160-8
Fuel
Tank
Evaporative
Control
System
.....
160-4
Relieving
fuel
pressure
and
connecting
fuel
pressure
gauge
..
.
...........
.
.
.
..
160-8
FUEL
LEVEL
SENDERS
.
.
.
.
.
.......
.
.
.
160-4
System
pressure,
testing
.................
160-9
Fuel
level
senders,
testing
.
.
.
.
.
.......
.
.
.
160-5
Fuel
delivery
volume,
testing
.............
160-10
Fuel
leve¡
sender
and
fuel
pump
(right
side),
emoving
and
installing
.
.
.
.
.
.
160-5
TABLES
Fuel
leve¡
sender
(left
side),
a
.
FuelLeve¡
Sender
Resistances
...........
.
.
..
.160-5
removing
and
installing
.........
.
.
.
.
.
.
.
160-6
b
.
Fuel
Pump
Current
...
.................
..
...
160-8
c
.
Fuel
Pressure
Specifications
..............
.
..
160-10
FUEL
PUMP
.
.
.
................
.
.
.
.
.
.
.
160-6
d
.
Fuel
Pump
Delivery
Specifications
.........
.
..
160-10
Fuel
Pump
Fuse
and
Relay
.
.
.
....
.
.
.
.
.
.
.
160-6
GENERAL
This
repair
group
covers
service
information
specifically
for
The
cautions
and
warnings
on
this
page
should
beob
the
fuel
supply
system
.
Information
on
the
fue¡
injection
sys-
served
when
servicing
the
fuel
system
.
tem
is
covered
in
130
Fuel
Injection
.
NOTE-
Fue¡
filter
replacement
is
covered
in
020
Maintenance
Program
.
WARNING
-
"
The
fuel
system
is
designed
to
retain
pressure
even
when
the
ignition
isoff
.
When
working
with
the
fuel
system,
loosen
the
fuel
lines
slowly
toal-
low
residual
fuel
pressure
to
dissipate
gradually
.
Avoid
spraying
fuel
.
"
Before
beginning
any
work
on
the
fuel
system,
place
a
tire
extinguisher
in
the
vicinity
of
the
work
area
.
"
Fuel
is
highly
flammable
.
When
working
around
fuel,
do
not
disconnect
any
wires
that
could
cause
electrical
sparks
.
Do
not
smoke
or
work
near
heaters
or
other
tire
hazards
.
"
Always
unscrew
the
fuel
tank
cap
to
release
pres-
sure
in
the
tank
before
working
on
the
tank
or
fines
.
"
Do
not
use
a
work
light
near
any
fuel
.
Fuel
may
spray
onto
the
hot
bulb
causing
a
tire
.
"
Make
sure
the
work
area
is
properly
ventifated
.
FUEL
TANK
AND
FUEL
PUMP
160-1
CAUTION-
"
Prior
to
disconnecting
the
battery,
read
the
bat-tery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
viü
.
"
Before
making
any
electrical
tests
with
the
ignition
tumed
on,
disable
the
ignition
system
as
de-
scribed
in
120
Ignition
System
.
Be
sure
the
bat-tery
is
disconnected
when
replacing
components
.
"
To
prevent
damage
to
the
ignition
system
or
the
electronic
fuel
system
components,
including
the
control
unit,
aiways
connect
and
disconnect
wires
and
test
equipment
with
the
ignition
off
.
"
Cleanliness
is
essential
when
working
with
the
fuel
system
.
Thoroughly
clean
the
fuel
fine
unionsbefore
disconnecting
any
of
the
fines
.
"
Use
only
clean
tools
.
Keep
removed
parts
clean
and
sealed
or
covered
with
a
clean,
lint-free
cloth,
especially
if
completion
of
the
repair
is
delayed
.
"
Do
not
move
the
car
while
the
fuel
system
is
open
.
"
Avoid
using
high
pressure
compressed
air
to
blow
out
fines
and
componente
.
High
pressure
can
rupture
infernal
seals
and
gaskets
.
"
Always
replace
seals
and
O-rings
.
GENERAL
Page 191 of 759
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
Page 194 of 759
160-
1
0
FUEL
TANK
AND
FUEL
PUMP
3
.
Operate
fuel
pump
as
described
earlier
under
Operat-
ing
fuel
pump
for
tests
.
Check
that
fuel
pressure
cor-
responds
to
specifications
listed
in
Table
c
.
"
If
system
pressure
is
low,
repeat
test
whilegradually
pinching
off
return
hose
.
Pressure
should
rise
rapidly
.
If
not,fuel
pump
is
most
likely
faulty
.
"
If
system
pressure
is
too
high,
check
return
line
from
pressure
regulator
to
tank
.
Check
for
kinks
in
hose
.
Blow
compressed
air
through
line
to
check
for
block-
ages
.
If
no
faulty
canbe
found,
pressure
regulator
is
most
likely
faulty
.
See
130
Fuel
Injection
for
testing
and
replacementprocedures
.
Table
c
.
Fuel
Pressure
Specifications
Engine
1
Fuel
pressure
4-cylinder
M42/M44
3
.0
:e
0
.06
bar(43
.5
±0
.9
psi)
6-cylinder
M50/S50US
3
.0
:j-
0
.06bar(43
.5
t0
.9
psi)
M52/S52US
3
.5
t
0
.06
bar
(51
t0
.9psi)
CA
UTION-
Do
not
use
compressed
air
above
40
psi
to
blow
out
fines
or
components
.
Interna¡
damage
to
com-
ponents
may
result
.
4
.
When
finished,
disconnect
pressure
gauge
.
FUEL
PUMP
Fuel
delivery
volume,
testing
1
.
Disconnect
return
line
from
fuel
rail
in
engine
compart-
ment
.
2
.
Connect
a
length
of
hose
to
fitting
on
fuel
rail
and
place
open
end
of
hose
in
a
suitable
container
for
catching
fuel
(2-quart
capacity)
.
3
.
Run
fuel
pump
for
exactly
30
seconds
as
described
earlier
under
Operating
fuel
pump
for
tests
and
mea-
sure
fuel
collected
.
Refer
to
Table
d
.
WARNING-
Table
d
.
Fuel
Pump
Delivery
Specifications
Fuel
under
pressure
is
present
duringthe
test
.
Use
I
Engine
Delivery
rate
(30
seconds
@
12V)
hose
clamps
at
all
connections
.
4-cylinder
M42/M44
0
.875
fter
(0
.93
qt)
6-cylinder
M50/S50US
0
.875
fter(0
.93
qt)
M52/S52US
~
1
.12
liter
(1
.16
qt)
4
.
When
finished
testing,
reconnect
fuel
line
.
Tighten
all
hose
clamps
.
NOTE-
It
is
common
practice
to
replace
the
fuel
filter
any
time
the
fuel
pump
unit
is
replaced
.
Page 198 of 759
170-
4
RADIATOR
AND
COOLING
SYSTEM
A
quick
testat
the
coolant
temperature
gauge
sender
can
The
auxiliary
cooling
fan
comes
on
when
coolant
tempera
determine
if
the
gauge
is
functioning
correctly
.
ture
exceeds
a
predetermined
leve¡
or
whenever
the
air
condi-
tioning
is
on
.
A
dual-range
temperature
switch
for
cooling
fan
lf
the
gauge
needie
remains
at
the
rest
position
with
theen-
control
is
mounted
on
the
right
side
of
the
radiator
.
See
Fig
.
3
.
gine
warm,
remove
the
harness
connector
from
the
sender
and
jumper
the
correct
terminals
in
the
connector
to
simulate
a
high
engine
temperature
.
See
Table
a
.
Turn
the
ignition
on
.
If
the
gauge
needle
moves
upward,
the
sender
is
faulty
.
If
the
gauge
does
not
respond,
the
wiring
to
the
gauge
is
broken
(open
circuit)
or
the
gauge
itselfis
faulty
.
WARNING
-
1996
and
laten
models
are
OBD
11
compliant
.
Dis-
connecting
electrical
connectors
wíth
the
ignition
turned
on
may
set
fault
codes
in
the
ECM
.
It
is
rec-
ommended
that
you
leave
the
diagnosis
of
faults
in
the
coolant
temperature
sensorsystem
to
the
BMW
dealer
service
department
which
has
specialized
OBD
11
scan
tool
equipment
.
If
the
gauge
needle
reads
too
high
when
the
engine
is
cold,
remove
the
harness
connector
from
the
sender
.
Turn
the
igni-
tion
on
.
lf
the
gauge
needle
position
does
not
change,
the
wir-
ing
or
the
gauge
is
shorted
to
ground
.
If
the
gauge
needle
drops,
the
sender
is
faulty
and
should
be
replaced
.
When
re-
placing
a
faulty
coolant
temperature
sender,
the
gasket
ring
on
the
sender
should
also
be
replaced
.
Tightening
Torque
"
Temperature
gauge
sender
to
engine
18
Nm
(13
ft-Ib)
Cooling
fan,
testing
NOTE-
OnM44
engines
with
manual
transmission,
the
primary
electric
cooling
fan
is
mounted
on
the
engine
side
of
the
radiator
and
is
controlled
by
the
engine
control
module
(ECM)
.
Troubleshooting
thiscircuit
should
be
left
to
an
authorized
BMW
dealer
with
the
proper
diagnostic
equipment
An
otherwise
sound
cooling
system
may
still
overheat,
par-
ticularly
with
prolonged
idling,
due
to
a
failure
of
the
coolíng
fan(s)
.
The
belt-driven
cooling
fan
is
controlled
by
a
temperature
dependent
viscous
clutch
.
A
failed
fan
clutch
may
affect
air
flow
through
the
radiator
resulting
in
overheating
orpossibly
overcooling
.
Speed
Low
sp
High
s
With
the
engine
off,
check
thefan
clutch
by
spinning
thefan
.
eed
The
fan
should
spin
on
the
clutch
with
some
resistance
.
peed
Check
for
signs
of
leaking
fluid
from
the
clutch
.
If
thefan
free-
wheels
with
no
resistance,
cannot
be
tu
rned
by
hand,
or
there
are
signs
of
oil
leakage,
the
clutch
should
be
replaced
.
TROUBLESHOOTING
Fig
.
3
.
Radiatorcooling
fan
temperature
switch
(arrow)
.
WARNING
-
"
Use
caution
when
testing
the
electric
cooling
fan(s)
and
coolant
temperature
switch
.
Keep
hands
and
wires
clear
of
thefan
blades
.
The
cool-
ing
fan(s)
can
run
any
time
the
ignition
is
ON
.
"
For
greatest
safety,
coolíng
fan
and
coolant
tem-perature
switch
tests
shouldbe
performed
on
acoldengine
with
the
air
conditioning
off
.
Table
b
.
Auxiliary
Cooling
Fan
Switching
Temperatures
Switching
temperature
196°F(91°C)
210°F(99°C)
0012506
If
a
faulty
thermostat,
trapped
air,
or
a
restriction
in
the
sys-
tem
is
not
allowing
the
coolant
to
circulate
through
the
radia-
tor,
the
temperature
switch
will
not
close
and
the
auxiliary
cooling
fan
will
not
run
.
Before
making
the
tests
described
be-
low,
make
sure
the
thermostat
is
operating
correctly
as
de-
scribed
earlier
.
The
normal
switching
temperatures
for
the
dual
-speed
switch
are
listed
in
Table
b
.