1997 BMW 328i rear

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

130-
1
0



FUEL
INJECTION

Relleving
fuel
pressure
and
connecting

fuel
pressure
gauge

WARNING
-

"
Gasoline
is
highly
flammable
and
its
vaporsare
explosive
.
Do
not
smoke
orwork
on
acarnear
heaters
or
other
fire
hazards
when
diagnosing
and
repairing
fuel
system
problems
.
Have
a
fire
extinguisher
available
in
case
of
an
emergency
.

"
When
working
onanopen
fuel
system,
wear
suit-
able
hand
protection
.
Prolonged
contact
with
fuel
can
cause
illnesses
and
skin
disorders
.

To
prevent
fuel
from
spraying
on
a
hot
engine,
system
fuel

pressure
should
be
relieved
before
disconnecting
fuel
lines
.

One
method
is
to
tightly
wrap
a
shop
towel
around
a
fuelline
fit-

ting
and
loosenor
disconnect
the
fitting
.

Cleanliness
is
essential
when
working
with
fuelcircuit
com-
ponents
.
Thoroughly
clean
theunionsbefore
disconnecting
fuellines
.

NOTE-

"
OnM44
engines,
a
Schrmder
valve
is
integrated
in
the
fuel
rail
.
Compressed
air
pressure
canbe
applied
at
the
valve
to
force
the
fuel
in
the
system
back
into
the
tank
.
See
Fig
.
11
.

0012503

Fig
.
11
.
Fuel
rail
showing
location
of
Schraeder
valve
fitting
on
M44
engine
(arrow)
.

NOTE-

B~
specifies
a
special
gauge
and
special
connecting
adapters
to
measure
fuel
pressure
.
If
the
special
tools
arenot
available,
a
length
of
fuel
fine
and
a
T-fitting
canbe
installed
to
the
inlet
fuel
fine
and
connected
to
a
fuel
gauge
.
On
some
vehicles,
thisis
not
possible
without
cutting
finto
a
fuel
lino
.
In
these
lnstances,
it
Is
recom-
mended
that
fuel
pressure
be
checked
at
theoutput
sidoof
the
fuel
pump
.
See
160
Fuel
Tankand
Fuel
Pump
.

FUELDELIVERY
TESTS

On
OBD
II
6-cylinder
engines,
the
fuel
lines
use
a
special

locking
fitting
.
Use
BMW
special
tool
16
1
050
to
release
the

fittings
and
connect
the
fuel
gauge
.
See
Fig
.
12
.

0012699

Fig
.
12
.
Fuel
linos
at
rear
of
intake
manifold
on
M52
engine
.
Use
BMW
special
tool
16
1
050
torelease
fittings
.

WARNING
-

"
Gasoline
is
highly
flammable
and
its
vapors
are
explosive
.

"
The
fuel
pressure
gauge
must
be
securely
con-nected
to
prevent
it
from
coming
loose
under
pressure
.

NOTE-

"
The
fuel
pressure
gauge
should
have
arangoof
0
to
5
bar
(0
to
75
psi)
.

"
On
6-cylinder
engine,
thetop
left-sido
engine
cover
will
have
to
be
removed
to
access
the
fuel
rail
.

Residual
fuel
pressure,
testing

For
quick
restarts
and
to
avoid
vapor
lock
when
the
engine
is
hot,
the
fuel
injection
system
is
designed
to
retain
fuel
pres-
sure
after
the
engine
has
been
turned
off
.
Thís
residualpres-
sure
is
primarily
maíntained
by
a
check
valve
at
the
fuel
pump
outiet
and
the
fuel
pressure
regulator
.
The
fuel
pump
check
valve
is
not
serviceable
asan
individual
part
.

1.
Relieve
fuel
pressure
and
connect
a
pressure
gauge
as
described
earlier
.

WARNING
-

Fuel
will
be
discharged
.
Wrap
a
shop
towel
around
the
fuellino
fitting
when
disconnecting
the
fuel
fine
.
Do
not
smoke
or
worknear
heaters
or
other
fire
hazards
.
Keep
an
approved
fire
extinguisher
handy
.

2
.
Operate
fuel
pump
for
approximately
one
minuto
by
by-
passing
fuel
pump
relay
as
described
earlier
.
Observe
fuel
pressure
.

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

130-26



FUEL
INJECTION

Throttle
position
sensor
(TPS),
replacing

The
throttie
position
sensor
is
located
on
the
side
of
the
throttie
housing
.
See
Fig
.
40
.

Fig
.
40
.
M52
engine
:
Throttle
position
sensor
(arrow)
.

1
.
Unplug
harness
connector
from
sensor
.

NOTE
-

On
cars
with
tractioncontrol,
do
not
confuse
the
throttieposition
sensor
on
the
main
throttie
body
wíth
the
throt-
tie
position
switch
on
the
secondary
throttie
body,
where
applicable
.

3
.
Installation
is
reverse
of
removal
.

¡die
speed
control
valve,
replacing

0012700b

The
¡die
speed
control
valve
is
mounted
on
the
underside
of
the
intake
manifoldadjacent
to
the
dipstick
tube
bracket
.
Ac-
cessing
the
valve
is
best
accomplished
by
first
removing
the
throttie
housing
.

1
.
Disconnect
intake
air
bootfrom
throttie
housing
.
Unbolt
throttie
body
and
¡ay
aside
.
(Do
not
disconnect
throttie
cable
or
electrical
harness
connectors
to
throttie
body
.)

2
.
Unbolt
dipstick
tube
bracket
from
intakemanifold
.

3
.
Workíng
under
intake
manifold,
disconnect
electrical
harness
connector
from
¡die
speed
control
valve
.

4
.
Remove
two
bolts
retaining
¡die
speed
control
valve
to
underside
of
intake
manifold
.
Remove
valve
from
intake
manifold
.
Remove
hose
clamp
and
disconnect
hose
.

ECM
PIN
ASSIGNMENTS

mately
one
minute
.

Vacuum
seal

Mounting
bracket

Electrical
connector

0013185

Fig
.
41
.
M52
engine
:
¡die
speed
control
valve
(located
under
intake
manifold)
.

5
.
Installation
ís
reverse
of
removal
.
Use
new
gaskets
when
installing
.

NOTE
-

Poor
driveabilíty
may
be
noticed
atter
installing
a
re-
placement
idle
speed
control
valve
.
After
about
10
min-utes
of
dríving
the
idle
speed
should
return
to
normal
.

ECM
PIN
ASSIGNMENTS

2
.
Remove
twomountingscrews
holding
sensor
to
throttie
housing
.



Engine
control
module
(ECM),
accessing

1
.
Disconnect
negative
(-)
battery
cable
.
Wait
approxi-

CAUTION-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
vüi
.

2
.
Remove
engine
control
module
(ECM)
compartment
cover
from
right
side
of
engine
compartment
rear
bulk-
head
.
Cover
is
retained
withfour
captíve
screws
.
See
Fig
.
42
.

3
.
Disconnect
control
module
harness
connector
by
re-
leasing
fastener
and
pivoting
connectorup
and
off
ECM
.

4
.
Remove
ECM
from
retaining
brackets
and
pull
ECM
from
its
holder
.

5
.
Installation
is
reverse
of
removal
.

0013ZIM
Fig
.
42
.
Engine
control
module
(ECM)
located
in
compartment
in
right-rearof
engine
compartment
(arrow)
.

NOTE-

Replacement
ECMs
must
be
coded
with
application
in-
formation
(Le
.
engine
code,
transmission
type,
etc
.)
pri-
or
to
installation
.
Consult
an
authorized
BMW
dealer
before
replacing
the
ECM
.

ECM
pin
assignments
are
given
in
Tables
h
through
Table
I.
This
information
can
be
helpful
when
diagnosing
faultsto
or
from
the
ECM
.
If
al¡
inputs
and
wiring
are
OK
butoperational
problems
still
exist,
the
ECM
itself
may
be
faulty
.

Fig
.
43
.
ECM
pin
numbers
as
seen
from
back
of
ECM
connector
.

FUEL
INJECTION



130-
2
7

Generally,
absence
of
voltage
or
continuity
means
there
is
a
wiring
or
connector
problem
.
Test
results
with
incorrect
values
do
notnecessarily
mean
that
a
component
is
faulty
:
Check
for
loose,
broken
or
corroded
connections
and
wiring
before
re-
placing
components
.
If
the
results
are
still
incorrect,
test
the
component
itself
.
For
engine
management
system
electrical
schematics,
see
Electrical
Wiring
Diagrams
.

CAUTION-

Always
waitat
least
40
seconds
after
tuniing
off
the
ignition
before
removing
the
connector
from
the
engine
control
module
(ECM)
.
If
the
connec-
tor
is
removed
before
this
time,
residual
power
in
the
system
relay
may
damage
the
ECM
.

"
Always
connector
disconnect
the
control
module
connector
and
meter
probes
with
the
ignitionoff
.

When
making
checks
at
the
ECM
itself,
a
breakout
box
should
be
used
to
allow
tests
to
be
made
with
the
connector
attached
to
the
ECM
.
This
also
prevents
damage
tothe
small
termínals
in
the
connector
.
As
an
alternative,
theharness
con-
nector
housing
can
be
separated
so
that
electrical
checks
can
be
made
from
the
back
of
the
connector
.
ECM
pin
numbering
is
shown
in
Fig
.
43
.

NOTE
-

On
cars
with
tractioncontrol,
do
not
confuse
the
throttle
position
sensor
on
the
main
throttle
body
with
the
throt-
tle
position
switch
on
the
secondary
throttle
body
.

27
Lb
2L4
LJ
22
©©®®17
©©®©©~©©®©~~rui~~ru

®®®®®®®®®®®®®®®IZA®®®®®®®®®®®®®®®®®

1
>I-
0013211

ECM
PIN
ASSIGNMENTS

160-2



FUEL
TANK
AND
FUEL
PUMP

0011943
1
.
Filler
pipe



10
.
Fuel
compensating
siphon
pump
and
hose
assembly
2
.
Filler
pipe
grounding
tab



(models
built
from
1/95)
3
.
Vent
pipe



11
.
Fueltank
4
.
Threaded
collar



12
.
Tank
support
strap
5
.
Rubber
ring
seal



13
.
Bolt-tighten
to
23
Nm
(17
ft-Ib)
6
.
Fuel
pump



14
.
Fuel
expansion
tank
7
.
Left
side
fuel
leve¡
sender(models
built
from
1/95)



15
.
Fuel
tank
pressure
sensor
(OBD
II)
8
.
Right
side
fuel
leve¡
sender9
.
Left
side
fuel
leve¡
sender
with
fuel
compensating
siphon
pump
(models
built
up
to
1/95)

Fig
.
1
.



E36
fuel
tank
assembly
.

FUEL
TANK
AND
LINES



Fuel
tank,
draining

The
plastic
fuel
tank
is
mounted
beneath
the
center
of
the
car
(beneath
rear
seat)
.
Mounted
in
the
fuel
tank
are
the
fuel
pump
and
fuel
leve¡
sending
units
.
Connecting
lines
for
the
evaporative
emission
control
systemand
expansion
tank
are
also
attached
to
the
tank
.
When
performing
the
procedures
that
follow,
refer
toFig
.
1
.

Fuel
tank
capacity
for
E36
modeis

"All
ex
.
1996
M3
(3
.0
L)
.....
.
..
..
65
liters
(17
.0
gal)

"
1996
M3
(3.0L)
modeis
.
...
.
..
.
.62
liters
(16
.4
gal)

FUEL
TA
NKAND
LINES

The
fuel
tank
should
be
drained
into
an
approved
storage
unit
or
another
car's
fuel
tank
.

WARNING
-
"
Before
removing
the
tank,
be
sure
that
afl
hot
components
such
as
the
exhaust
system,
are
completely
cooled
down
.

"
Fuel
may
be
spilled
.
Do
not
smoke
or
worknear
heaters
or
other
Pire
hazards
.

1
.
Disconnect
negative
(-)
cable
from
battery
.

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
on
paga
vi¡¡
.

2
.
Remove
fuel
tank
filler
cap
.

3
.
Remove
rearseat
cushion
and
pull
back
insulation
mats
to
expose
fuel
tank
access
covers
.
See
Fig
.
2
.

uui3140

Fig
.
2
.



Right
side
fuel
tank
access
cover
under
rear
seat
cushion
.

4
.
Remove
right
and
left
access
covers
to
expose
fuel
hoses
and
electrical
connections
at
tank
.

5
.
Label
fuel
hoses
.
Then
disconnect
hoses
and
harness
connectors
from
fuel
sending
units
and
fuel
pump
.
See
Fig
.
3
.

FUELTANK
AND
FUEL
PUMP



160-
3

NOTE-

"
If
necessary,
push
fuel
level
sender
arm
toward
fuel
pump
assembly
to
facilitate
removal
.

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

"
Pump
out
contents
of
each
tanklobe
using
approved
pumpinglextraction
equipment
and
flexible
fuel-grade
hose
.

WARNING
-

Fuel
may
be
spilled
.
Do
not
smoke
or
work
near
heaters
or
other
fire
hazards
.

7
.
Installation
of
sending
units
is
reverse
of
removal,
not-
ing
the
following
:

"
Use
new
sealing
rings
when
installing
pump/sending
unit
assemblies
.
"
Be
sure
that
fuel
line
connections
point
in
same
direc-tion
as
they
carne
out
.
"
Fill
tank
and
check
for
leaks
by
running
engine
.

CA
UTION-

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
tank,
removing
and
installing

1.
Disconnect
negative
(-)cablefrom
battery
:

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
viii
.

2
.
Remove
fuel
tank
filler
capand
drain
tank
as
described
earlier
.

3
.
Working
in
left
access
tank
access
hole
(under
rear

seat
cushion),
remove
vent
pipe
fromtank
.

4
.
Working
inside
car,
disconnectparking
brake
cable
ends
from
parking
brake
lever
.
See
340
Brakes
.

5
.
Working
underneath
car,
gently
pry
fuel
lines
away
from
retaining
bracket
in
front
of
tank
.
Remove
clamps
and
disconnect
fuel
hoses
as
shown
in
Fig
.
4
.

6
.
Remove
exhaust
system
and
heat
shield
as
described

ooisiai



in
180
Exhaust
System
.
See
Fig
.
5
.

Fig
.
3
.



Fuel
pump/fuel
level
sender
assembly
in
top
offuel
tank
(right
side
shown)
.
Disconnect
supply
hose
(A),
return
hose
(B)
and



7
.
Remove
driveshaft
.
See
260
Driveshaft
.
harness
connector
(C)
.

8
.
Pull
parking
brake
cables
backward
away
from
bottom
of

6
.
Unscrew
threaded
collars
from
fuel
tank
.
Slowly
with-



fuel
tank,
disengaging
them
from
brackets
as
needed
.

draw
fuel
sender
assemblies
from
tank,allowing
fuel
to
drain
off
.

FUEL
TANKAND
LINES

160-
4



FUEL
TANK
AND
FUEL
PUMP

Fig
.
4
.



Pinch
off
supply
and
retum
fuel
hoses
(arrows)
before
dis-
connecting
from
rigid
metal
lines
.

0013143

Fig
.
5
.
After
removing
exhaustsystem,
remove
heat
shield
screws
(arrows)
and
heat
shield
.

9
.
Working
underneath
car,
loosen
hose
clamp
and
dis-

connect
filler
hose
.

10
.
Support
tank
from
below
.
Remove
tank
strap
mounting

bolts
.
Lower
and
remove
tank,
disconnecting
right
side



TheE36
model
uses
a
two-lobed
fuel
tank
and
each
lobeof
vent
and
other
hoses/electrical
connectors
as
neces-



the
tank
has
its
own
fuel
level
sending
unit
.
sary
.

11
.
Installation
is
reverse
of
removal
.

"
Always
use
new
seals,
gaskets,
O-rings,
and
hose
clamps
.

"
Inspect
hoses
and
replace
any
that
are
chafed,
dried

outor
cracked
.

"
Inspect
heat
shield
and
replace
if
corroded
.

"
Inspect
rubber
buffers
and
liners
on
fuel
tank,
support
straps
and
on
underside
of
body
.
Replace
rubber

parts
that
are
hardened
or
damaged
.

FUEL
LEVEL
SENDERS

CAUTION-

"
Before
starting
the
engine,
fill
the
fuel
tank
with
at
least
1.5
gallons
(5
liters)
of
fuel
to
prevent

damaging
a
dry
fuel
pump
.

"
If
the
filler
neck
has
been
removed
from
the
body,
be
sure
toreattach
theneck's
grounding
screw
(where
applicable)
.
Check
electrical
resistance
between
the
ground
tab
and
wheel
hub
.
The
re-
sistance
shouldbeno
higher
than
0
.6
ohms
.

Tightening
Torques

"
Fuel
tank
to
body
.............
...
23
Nm
(17
ft-Ib)

"
Hose
clamps
(10
mm-16
mm
día
.)
..
2
.0
Nm
(18
in-lb)

Fuel
Tank
Evaporative
Control
System

The
fuel
tank
evaporative
control
system
is
used
to
vent
the

fuel
tank
to
a
charcoal
canister,
which
is
then
purgedby
en-

gine
vacuum
during
normal
engine
operatíon
.
This
controls

emission
of
raw
hydrocarbons
(fuel)
to
the
atmosphere
.
See

Fig
.
1
.

A
fuel
expansion
tank,
located
under
the
right
rear
fender,

traps
overflow
fuel
and
incorporates
extra
fuel
tank
plumbing
.

Startingwith
1996
models,
OBD
II
standards
require
that

the
fuel
tank
evaporative
control
system
be
monitored
for

leaks
.
This
is
accomplished
usingthe
fuel
tankpressuresen-

sor,
the
ventshut
off
valve,
and
the
evaporative
purge
valve
.

NOTE-

On
most
early
cars(1992-1995),
the
charcoal
canister

is
in
the
engine
compartment
.
On
latercars,
the
char-
coal
canister
is
under
the
spare
tire
in
the
luggage
com-
partment
.

FUEL
LEVEL
SENDERS

The
right
side
fuel
leve¡
sender
is
integrated
with
the
fuel

pump
.
Each
senderhas
a
float
connected
to
a
variable
resis-

tance
for
fuel
leve¡
.
When
replacing
the
sender/pump
assem-

bly
always
replace
hose
clamps,gaskets
and
O-rings
.

WARNING
-

When
removing
the
fuel
level
sender
or
the
fuel
pump,
the
fuel
tank
should
be
emptied
.