fuel line BMW 325i 1992 E36 Owner's Guide

Tableh
.
ECM
Pin
Assignment--Bosch
DME
M1
.7

Pin



1
Signal



1
Component/function



1
Signal

45
Notused

46
Notused

47
Notused

48



Output



A/C
compressor
cut-out



Compressor
control
relay,
terminal
85
49
Notused

50
Notused

51



Output



Cyl
.
4
ignition
coil
control



Cyl
.
4
ignition
coil

52



Output



Cyl
.
2
ignition
coil
control



Cyl
.
2
ignition
coil

53



Not
used
54



Input



Battery
voltage
from
engine
control
module



Engine
control
module
relay,
terminal
87a

55



Ground



Ground,
ignition



Ground
point

56



Input



Ignition
switch,
terminal
15



Ignition
switch,
terminal
15
57
Notused

58



Not
used

59



Output



Throttleposition
sensor
and
volume
air
flow
sensor



Reference
voltage
(5
VDC)

60



Input



Programming
voltage



Data
link
connector

61
Notused

62
Notused

63
Notused

64



Input



Ignition
timing
intervention



Transmission
control
module
(EGS)

65



Input



Drive
range
P/N



Automatic
transmission
range
switch

66
Notused

67



Input



Crankshaft
position
RPM
sensor



Crankshaft
position
RPM
sensor

68



Input



Crankshaft
position
RPM
sensor



Crankshaft
position
RPM
sensor

69
Notused

70



Input



Oxygen
sensor
signal



Heated
oxygen
sensor

71



Ground



Oxygen
sensor
signal
ground



Heated
oxygen
sensor

72
Notused

73



Input



Vehicle
speed
signal



Instrument
cluster

74



Output



Engine
speed
signal



Instrument
cluster

75



Not
used
76



Input



Volume
air
flow
sensor



Volume
air
flow
sensor

77



Input



Intake
air
temperature
sensor
(IAT)



Intake
air
temperature
sensor
(IAT)

78



Input



Engine
coolant
temperature



Engine
coolant
temperature
sensor

79
Notused

80



Not
used

81



Input



Drive-away
protection
signal
(code)



On-boardcomputer

82



Not
used
83
Notused

84



Not
used
85



Input



A/C
pressure



Pressure
switch

86



Input



A/C
switch



Integrated
climate
regulation
control
module

87



Output



RxD
diagnosisdata
line



Data
link
connector

88



Output-Input



TxD
diagnosisdata
line



l
Data
link
connector

FUEL
INJECTION



130-
2
9

ECM
PIN
ASSIGNMENTS

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

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
.

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

160-
6



FUEL
TANK
AND
FUEL
PUMP

Fig
.
7
.



Fuel
sender
and
pump
assembly
.

To
operate
the
fuel
pump
for
testing
purposes
without
hav-
Fuel
leve¡
sender
(left
side),



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

removing
and
installing



powerthe
pump
directly
.

The
procedure
for
removing
and
replacing
the
left
side
fuel



To
runthe
fuel
pump,
remove
the
relay
and
connect
the
leve¡
sender
is
similar
tothat
used
for
the
right
side
.
There
is



socket
for
relayterminal
30
to
the
socket
for
relay
terminal
no
.
no
fuel
pump
on
the
left
side
.



87
with
afused
jumper
wire
.
Relay
terminal
identification
is
shown
in
Fig
.
9
.
After
completing
the
tests,
remove
the
jumper

wire
.

FUEL
PUMP

The
electric
fuel
pump
ís
mounted
in
the
fuel
tank
in
tandem
with
the
right
side
fuelleve¡
sender
.
The
fuel
pump
delivers
fuel
at
high
pressure
to
the
fuel
injection
system
.
A
pressure
regulator
maintains
system
pressure
.
The
quantity
of
fuel
sup-
plied
exceeds
demand,
so
excess
fuel
retums
to
the
fuel
tank
via
a
retum
líne
.
See
130
Fuel
Injection
for
more
information
on
system
pressure
and
the
fuel
pressure
regulator
.

NOTE
-

Fuel
pump
removalprocedures
are
given
earlier
under
Fuel
leve¡
sender
(right
side)
and
fuel
pump,
remov-
íng
and
installing
.

Fuel
Pump
Fuse
and
Relay

The
fuel
pump
is
operated
by
a
fuel
pump
relay
located
ín
the
power
distribution
box
.
The
fuel
pump
circuit
is
protected
by
fuse
no
.
18
located
in
the
power
distribution
box
.
See
Fig
8
.

FUEL
PUMP

0013142

Fuel



DM
E
PUMP
main
re
ay



rel
ay

0

aoo
o
~a

aao
ó

Fig
.
8
.



Fuel
pump
relay
location
in
power
distribution
box
.

The
DME
engine
control
module
(ECM)
and
the
DME
main

relay
supply
power
to
the
coi¡
sideof
the
fuel
pump
relay
.
Dur-

ing
starting,
the
fuel
pump
runs
as
long
as
the
ignition
switch
is
in
the
start
position
and
continues
to
run
oncethe
engine

starts
.
If
an
electrical
system
fault
interrupts
power
to
the
fuel
pump,
the
engine
will
notrun
.

Operating
fuel
pump
for
tests

CA
UTION-

Relay
locations
may
vary
.
Use
care
when
identify-
ing
relays
and
when
troubleshooting
the
electrical
system
at
the
fuselrelay
panel
.
The
fuel
pump
re-
¡ay
is
a
four
pin
relay
and
has
a
1.5
mm
2
red
wireat
terminal
30
in
the
relay
socket,
lf
in
doubt,
con-
sult
an
authorized
BMW
dealer
.

NOTE-

Thejumper
wire
shouldbe
1.5
mm2
(14
ga
.)
and
in-
clude
en
in-fine
fuse
holder
with
a16
amp
fuse
.
To
avoid
fuselrelay
panel
damage
fromrepeated
connect-
íng
and
disconnecting,
also
include
a
toggleswitch
.
A
heavy-duty
jumper,
BMW
tool
no
.
613
050,
fs
also
available
from
en
authorized
BMW
dealer
.

0013034,

If
the
pump
does
notrun
with
the
jumper
installed,
the
fault
could
be
in
the
fuel
pump
or
the
wiring
to
the
pump
.
Check
the
pump
and
its
wiring
as
described
below
.

160-
8



FUEL
TANK
AND
FUEL
PUMP

UU131
tst5

Fig
.
11
.
Voltage
supply
to
fuel
pump
harness
(black)
connector
being
checked
(arrow)
.

00131ts7

Fig
.
12
.
Test
fuel
pump
for
current
draw
by
attadhing
ammeter
andjumper
wire
as
shown
.

CAUTION-

Do
not
allow
the
test
leads
to
short
to
ground
.

NOTE-

See
600
Electrical
System-General
for
information
on
electricaltests
using
a
digital
multimeter
(DMM)
.

4
.
Run
pump
as
described
in
Operating
fuel
pump
for
tests
.

FUEL
PUMP

5
.
Compare
ammeter
reading
with
specification
listed
in

Table
b
.

Maximum
current



5
.0
amps
consumption

FuelDelivery
Tests

Table
b
.
Fuel
Pump
Current

Checking
fuel
delivery
is
a
fundamental
part
of
trouble-

shooting
and
diagnosing
the
DME
system
.
Fuelpressure
di-

rectly
influences
fuel
delivery
.
An
accurate
fuel
pressure

gauge
will
be
needed
to
make
the
tests
.

There
arethree
significant
fuel
delivery
values
to
bemea-

sured
:

"
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,
suchas
clogged
fuel
filter
.

"
Residual
pressure-the
pressure
maintained
in
the

closed
system
after
the
engine
and
fuel
pump
areshut

off
.

Procedures
for
measuring
the
first
two
quantities
arede-

scribed
here
.

Residual
fuel
pressure
is
checked
using
the
procedurede-

tailed
in
130
Fuel
Injection
.

Relieving
fuel
pressure
and
connecting

fuel
pressure
gauge

WARNING
-

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

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

CA
UTION-

Cleanliness
is
essential
when
working
withfuel
circuit
components
.
Thoroughly
clean
the
unionsbefore
disconnecting
fuel
fines

To
prevent
fuel
from
spraying
on
a
hotengine,
system
fuel

pressure
should
be
relieved
before
disconnecting
fuel
lines
.

One
method
is
to
tightly
wrap
a
shop
towel
around
a
fuel
line
fit-
ting
and
loosen
or
disconnect
the
fitting
.

Measuring
fuel
pressure
requires
special
tools
.
Earlier
cars
use
pressure
hose
with
clamps
for
fuel
delivery
.
These
can
be
attached
to
a
fuel
pressure
gauge
below
the
intake
manifold
.

NOTE-



NOTE
-

On
1996
and
later
4-cylinder
cars,
use
BMW
special



"
Use
BMW
pressure
gauge
Part
No
.
133
060,or
an
tool
13
6051
(hose
with
quick
release
coupling)
toat-



equivalent
.
The
fuel
pressure
gauge
should
have
a
tach
pressure
gauge
to
Shraeder
valve
fitting
on
top
of



rangeof
0
to
5bar
(0
to
75
psi)
and
mustbe
securely
the
M44
fuel
rail
.
See
Fig
.
13
.



connected
to
prevent
it
from
coming
loose
under
pres-
sure
.

u012503a

Fig
.
13
.
Fuel
rail
showing
location
of
Shrader
valve
fitting
on
M44
en-
gine
(arrow)
.

Later
model
6-cylinder
fuel
systems
require
BMW
specíal

tool
16
1
050
to
release
fittings
and
connect
the
fuel
gauge
.
See
Fig
.
14
.

0012699

Fig
.
14
.
Fuel
lines
at
rear
of
íntake
manifold
on
M52
engine
.
Use
BMW

special
tool
16
1
050
to
release
fittings
.

If
the
special
tools
arenot
available,
a
length
offuel
line
and

a
T-fitting
can
be
installed
tothe
inlet
fuel
line
and
connected

to
a
fuel
gauge
.

FUEL
TANK
AND
FUEL
PUMP



160-
9

"
On
cars
with
6-cylinder
engine,
thetop
left-side
en-
Bine
cover
will
have
to
be
removed
to
access
the
fuel
rail
.

System
pressure,
testing

System
pressure
is
the
pressure
created
by
the
fuel
pump
and
maintained
by
the
pressure
regulator
.
See
Fig
.
15
.
Sys-
tem
pressure
is
not
adjustable
.

1
.
Remove
fuel
tank
filler
cap
.

Fig
.
15
.
Fuel
pressure
regulator
.
Fuel
pressure
deflects
diaphragm
to
retum
fuel
to
tank
when
pressure
reaches
desired
limit
.

CA
UTION-

The
fuel
pump
is
capable
of
developing
a
higher
pressure
than
that
regulated
by
the
pressure
reg-
ulator
.
In
the
event
the
fuel
pump
check
valve
is
faulty
(stuck
closed),
make
sure
the
fuel
pressure
does
not
rise
aboye
6
.0
bar(87
psi)
.
Damage
to
the
fuel
fines
or
fuel
system
components
could
re-
sult
.

2
.
Connect
in-fine
a
Tfitting
and
fuel
pressure
gauge
to

outlet
hose
atfuel
pump
.

FUEL
PUMP

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
.