130-2
FUEL
INJECTION
GENERAL
This
repair
group
covers
fuel
injection
system
component
testing
and
repair
.
Special
equipment
is
necessary
for
some
of
the
procedures
given
in
this
repair
group
.
If
you
do
not
have
the
equipment
required
to
do
the
job,
it
is
recommended
that
these
repairs
be
left
to
an
authorized
BMW
dealer
.
The
BMW
dealer
is
equipped
with
sophisticated
diagnostic
test
equip-
ment
that
is
capable
of
quicklypinpointing
hard-to-find
fuel
in-
jection
problems
.
NOTE-
"
Wiring
diagrams
for
the
engine
management
system,
can
be
found
at
the
rear
of
the
manual
under
Electri-
cal
Wiring
Diagrams
.
"
For
ignition
system
repairinformation,
see120
Igni-
tion
System
.
"
For
fuel
supply
system
testing
and
repair,
see160
The
engine
control
module
(ECM)
uses
electrical
signals
Fuel
Tank
and
Fuel
Pump
.
from
the
mass
air
flow
sensor,
the
air
and
coolant
temperature
sensors,
the
crankshaft
position/rpm
sensor,
the
knock
sen
Principies
Of
Operation
sors
and
the
oxygen
sensorsas
the
primary
inputs
to
electron-
ically
control
fuel
delivery
and
ignition
timing
.
There
are
five
versions
of
engine
management
systems
usedon
the
E36
cars
.
Each
has
the
same
basic
components
and
operating
principles
.
The
most
notable
difference
is
that
1996
and
later
cars
use
a
sophisticated
OBD
II-compliant
sys-
tem
.
See
Table
a
.
Table
a
.
Engine
Management
System
Variants
Engine
code/year
1
System
4-cy1inder
M42
(1
.8
I)
1992-1995
Bosch
DME
Ml
.7
M44
(1
.91)
1996-1998
~
Bosch
DME
M5
.2
(OBD
II)
6-cylinder
M50
1992
(2.5
I)
Bosch
DME
M3
.1
1993-1995
(2.5
I)
Bosch
DME
M3
.3.1
(VANOS)
M52
1996-1998
(3281-
2
.8
I)
Siemens
MS
41
.1
(OBD
II)
1998
(3231
-
2
.5
I)
Siemens
MS
41
.1
(OBD
II)
M-Power
S50US
(M3
-
3
.01)
1995
Bosch
DME
M3
.3
.1
S52US
(M3
-
3
.21)
1997-1998
Siemens
MS
41
.1
(0131)
11)
NOTE-
-
Descriptions
and
procedures
in
the
first
partof
this
re-
pairgroup
refer
to
all
the
various
engine
management
systems
.
"
Particulars
of
each
fuel
injection
system
are
treated
in
separate
sections
in
the
second
part
of
this
repair
group
.
GENERAL
Fig
.1
.
OBD
II
diagnostic
connector
locatíon
.
The
fuel
injection
system
is
completely
electronic
in
opera-
tion
.
Air
flow
is
measured
electronically
via
a
mass
air
flow
sensor
and
additional
sensors
supply
information
about
en-
gine
operating
conditions
.
The
ECM
calculates
the
amount
of
fuel
needed
for
the
correct
air-fuel
ratio
and
actuates
the
fuel
injectors
accordingly
.
The
amount
offuel
metered
to
theen-
gine
is
determined
by
how
long
the
injectors
are
open
.
Airintake
.
Air
entering
the
engine
passes
through
a
pleat-
ed
paper
air
filter
in
the
air
cleaner
.
Intake
air
volume
or
mass
is
then
measured
bya
mass
air
flow
(MAF)
sensor
.
In
al¡
ex-
cept
the
vane
type
sensor
(DME
M1
.7),
a
reference
current
is
used
to
heat
a
thin
wireor
film
in
the
sensor
when
the
engine
is
running
.
The
current
used
to
heat
the
wire/film
is
electroni-
cally
converted
into
a
voltage
measurement
corresponding
to
the
mass
of
the
intake
air
.
Table
b
.
Mass
Air
Flow
Sensor
Variants
System
Al
r
flow
sensor
type
Bosch
DME
M1
.7
Vane
(volume
sensor)
Bosch
DME
M3
.1
Hot
wire
(mass
sensor)
Bosch
DME
M3
.3
.1
Hot
film
(mass
sensor)
Bosch
DME
M5
.2
Hot
film
(mass
sensor)
Siemens
MS
41
.1
Hot
film
(mass
sensor)
"
The
16-pin
OBD
11
diagnostic
connector
is
located
on
NOTE-
the
lower
left
dashpanel
.
See
Fig
.
1
.
On
cars
equipped
wíth
tractioncontrol,
an
additional
throttle
valve
is
controlled
by
an
electronic
throttle
actu-
ator
(motor)
.
This
valve
is
used
for
engine
speed
inter
vention
.
Repair
information
forthis
system
is
notcovered
here
due
to
the
special
electrical
testing
equip-
ment
required
to
service
it
.
170-10
RADIATOR
AND
COOLING
SYSTEM
Coolant
pump,
replacing
The
engine
coolant
pump
is
mounted
in
the
frontof
the
en-
gine
on
the
timing
cover
.
See
Fig
.
16
.
Fig
.
16
.
Coolant
pump
mounted
on
timing
cover
.
NOTE-
Onlyreplacement
coolant
pumps
with
metal
¡mpellers
should
be
installed
.
Pumps
with
plastic
impellers
should
not
be
used
.
1.
Drain
cooling
system
as
described
earlier
.
0013197
WARNING
-
Allow
cool¡ng
system
to
cool
before
open¡ngor
drain¡ng
system
.
2
.
Remove
primary
cooling
fan
shroud
and
cooling
fan
(belt-driven
or
electric)
as
described
earlier
.
Fig
.
17
.
Engine
drive
belt
tensioner
being
released
on
M44
engine
.
Pry
off
tensioner
cover
and
then
lever
tensioner
in
counterciock-
wise
direction
(as
facing
engine)
and
slip
belt
off
pulleys
.
Fig
.
18
.
Drive
belt
tensioner
being
released
on
M52
engine
.
Pry
off
3
.
Disconnect
hoses
from
thermostat
housing
.
Unbolt
tensioner
cover
and
then
lever
tensioner
clockwise
(as
facing
thermostat
housing
from
front
of
cylinder
head
.
engine)torelease
belt
tension
.
4
.
Remove
coolant
pump
drive
belt
.
See
Fig
.
17
or
Fig
.
18
.
NOTE-
-
Mark
direction
of
drive
belt
rotation
if
reusing
belt
.
"
The
6-cylinder
coolant
pump
¡s
mounted
on
studs
and
retained
by
nuts
.
"
Severa¡
drive
belt
and
tensioner
configurations
havebeenused
in
E36
models
.
Refer
to
020
Maintenance
Program
and
640
Heating
and
Air
Conditioning
.
5
.
Remove
coolant
pump
pulley
from
pump
.
6
.
Remove
mounting
fasteners
from
pump
.
COOLING
SYSTEM
SERVICE
NOTE-
"
The
4-cylinder
coolant
pump
¡s
mounted
us¡ng
two
dif-
terent
length
bolts
.
Note
where
thelonger
bolt
fits
dur-
ing
disassembly
.
0011989
7
.
Insert
twoscrews
(M6)
in
tapped
bores
and
tighten
uni-
formly
until
pump
is
free
from
timing
chain
cover
.
See
Fig
.
19
.
Fig
.
19
.
Coolant
pump
being
removed
.
Thread
two
M6
bolts
(arrows)
in
evenly
to
withdraw
pump
.
(Thermostat
and
hoseshavebeen
removed
tor
visual
access
.)
8
.
Installation
is
reverse
of
removal
.
"
Be
sure
to
replace
O-ring
and
gaskets
.
"
Coat
O-ring
with
lubricant
during
installation
.
Tightening
Torque
"
Coolant
pump
to
timing
chaincover
M6
...
.
...................
..
.
.
10
Nm
(89
in-lb)
M8
.
..
.
....................
.
.
.
22
Nm
(17
ft-Ib)
"
Coolant
pump
pulley
to
coolant
pump
.................
10
Nm
(89
in-lb)
RADIATOR
SERVICE
Radiator,
removing
and
installing
1
.
Drain
radiator
as
described
earlier
.
WARNING
-
Allow
cooling
system
to
cool
before
opening
ordraining
system
.
2
.
Remove
primary
cooling
fan
(belt-driven
or
electric)
as
described
earlier
.
3
.
Disconnect
coolingfan
and
leve¡
sensor
harness
con-
nectors
from
bottom
of
radiator,
where
applicable
4
.
Disconnect
harness
connector
from
auxiliary
fandual
temperature
switch
.
See
Fig
.
20
.
5
.
Disconnect
all
coolant
hoses
from
radiator
.
RADIATOR
AND
COOLING
SYSTEM
170-11
0012500
Fig
.
20
.
Cooling
fan
dual
temperatura
switch
(arrow)
on
right
sido
of
radiator
.
6
.
Where
applicable,
disconnectautomatic
transmission
fluid
(ATF)
cooler
lines
from
radiator
.
See
Fig
.
21
.
Fig
.
21
.
Automatic
transmission
fluid
(ATF)
linos
at
radiator
.
7
.
Carefully
pryout
radiator
retaining
clips
from
top
of
ra-
diator
.
See
Fig
.
22
.
8
.
Pul¡
radiator
up
and
out
of
car
.
NOTE-
The
radiator
rests
ontwo
rubber
mounts
.
Check
that
the
mounts
do
not
stick
to
the
bottomof
the
radiator
.
RADIATOR
SERVICE
