rear BMW 328i 1997 E36 Repair Manual

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

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
.

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

130-
8



FUEL
INJECTION

Fig
.
8
.



Fuel
pump
relayterminal
identification
.
1.
Peel
back
rubber
boot
on
oxygen
sensor
electrical
har-
ness
connector
(car
wiring
side)
.
With
connector
at-
Oxygen
sensor,
testing



tached
to
sensor,
connect
digital
voltmeter
to
pins
1
(BOSch
systems
only)



and
2
in
rear
of
connector
.
See
Fig
.
10
.

CAUTION-

"
The
information
inthis
sectionapplies
to
Bosch
engine
management
systems
only
.

"
The
Siemens
MS
41
.1
system
uses
resistive-type
oxygen
sensors
.
This
sensor
uses
a
5-volt
refer-
ence
signal
input
and
the
output
to
the
ECM
var-
ees
from
1-5
volts,
in
stepped
increments
based
on
oxygen
content
in
the
exhaust
.

NOTE-

"
On
pre-08D
11(1992-1995)
cars,
there
is
one
oxygen
sensor
mounted
upstream
of
the
catalytic
convert-
er(s)
in
the
exhaust
pipe
.
See
Fig
.
9
.
"
On
OBD
11
cars
(1996-1998)
cars,
there
is
one
oxygen
sensor
before
andone
after
each
catalytic
converter
.

"
OnM52
and
S52US
engines,
the
front
pairof
oxygen
sensors
are
installed
in
the
exhaust
manifolds
.

The
oxygen
sensor
providesan
input
voltage
signal
(0-1
VDC)
to
the
ECM
based
on
the
oxygen
content
in
the
exhaust
gas
.
TO
generate
voltage,
the
sensor
temperature
must
exceed
575°F
(300°C)
.
Therefore
it
ís
electrically
heated
.

NOTE-

"
The
test
given
below
is
not
a
conclusive
test
of
oxygen
sensor
efficiency
and
does
not
test
how
quickly
the
oxygensensor
can
react
to
changing
conditions
.

"
Pin
numbers
and
wirecolors
can
vary
.
Always
check
the
wiring
diagrams
to
conflrm
wire
color
and
pinas-
signment
.

ELECTRICAL
CHECKS
AND
COMPONENT
TESTING

0013135

Fig
.
9
.



Oxygen
sensor
location
(arrow)
ahead
of
catalytic
converter
.
3181
model
with
M42
engine
shown
.

1
.
Black
(ground)
2
.
Grey
(signal)



4
.
White
(heater
circuit)
3
.
White
(heater
circuit)

0013189
Fig
.
10
.
Oxygen
sensor
connector
terminal
identification
(sensor
sede)
.
Terminals
numbers
are
molded
into
connector
.

2
.
Start
engine
.
Oxygen
sensorshould
start
to
output
a
fluctuating
voltage
within
a
short
period
.
If
voltage
is
in-
correct,
turn
engine
off
and
check
preheater
circuit
as
described
below
.

WARNING
-

Exhaust
manifolds
and
pipes
can
be
hot
enough
to
cause
serious
burns
.
Wear
suitable
heavy
gloves
and
other
appropriate
protection
.

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¡¡
.