1997 BMW 328i air pump
[x] Cancel search: air pumpPage 116 of 759
119-2
LUBRICATION
SYSTEM
NOTE-
Component
Location
If
the
light
does
not
go
out,
thewiring
to
theswitch
is"
Oil
pressure
switch
most
likely
grounded
somewhere
between
the
switch
all
engines
.......
...
.
..
......
ora
oil
filter
housing
terminal
and
the
warning
light
.
Sea
Electrical
Wiring
Diagrams
atrearof
manual
for
electrical
schematics
.
CAUTION-
Some
oil
may
drain
out
as
the
oil
pressure
switch
is
removed
.
Use
a
rag
to
soak
up
any
spills
.
2
.
Install
pressure
gauge
in
place
of
switch
.
3
.
With
gauge
instalied,
start
engine
and
allow
to
reach
operating
temperature
.
Check
oil
pressureboth
cold
and
hot
.
NOTE-
For
the
most
accurate
test
results,
the
engine
oil
(and
filter)
shouldbe
newand
of
the
correct
grade
.
Oil
Pressure
"
¡dle
(mínimum)
..
.
.
..............
.
.
0
.5
bar
(7psi)
"
Regulated
pressure
(elevated
engine
speed)
4-cylinder
engines
..
......
4
.3
±
0
.2
bar
(63
t3
psi)
6-cylinder
engines
.
.
.............
.
4
.0
bar
(59
psi)
4
.
Remove
pressure
gauge
and
reinstall
pressure
switch
.
If
testing
shows
low
oil
pressure,
one
or
more
of
the
follow-
ing
conditions
may
be
indicated
:
OIL
PAN
"
Worn
or
faulty
oii
pump
.
"
Worn
or
faulty
engine
bearings
The
oil
pancan
be
removed
with
the
engine
instalied,
al-
Severe
engine
wear
.
though
specíal
enginesupport
equipment
will
be
needed
.
Al¡
of
these
conditionsindicate
the
need
for
major
repairs
.
Oil
pressure
warning
system,
testing
When
the
ignition
is
tumed
ora,
the
oil
pressure
warning
light
comes
ora
.
When
the
engine
ís
started
and
the
oil
pressure
ris-
es
slightly,
the
oil
pressure
switch
opens
and
thewarning
light
goes
out
.
Make
sure
the
oil
leve¡
is
correct
before
making
tests
.
1
.
Turra
ignition
switch
ora
.
"
Warning
light
ora
instrument
panel
must
light
up
.
2
.
Remove
connector
from
oil
pressure
switch
.
"
Warning
light
ora
instrument
panel
must
go
out
.
OIL
PAN
3
.
If
warning
light
does
not
light
when
ignition
is
ora,
re-
move
connector
from
oil
pressure
switch
anduse
a
jumper
wire
to
ground
connector
terminal
to
a
clean
metal
surface
.
NOTE
-
If
the
warning
light
comes
ora,
check
the
switch
as
de-
scríbed
in
the
nextstep
.
If
the
warning
light
does
not
come
ora,
thewiring
to
the
instrument
cluster
or
to
the
light
itself
isfaulty
.
4
.
To
test
switch,
connect
ara
ohmmeter
between
terminal
in
switch
body
and
ground
.
With
engine
off,
these
should
be
continuity
.
With
engine
running,
oil
pressure
should
opera
switch
and
there
should
beno
continuity
Replace
a
faulty
switch
.
WARNING
-
Keep
in
mind
that
low
oil
pressure
may
be
prevent-
ing
the
switch
from
tuming
the
light
out
.
If
the
light
remains
ora
while
the
engine
is
running,
check
the
oil
pressure
asdescribed
earlier
.
Do
not
drive
the
car
until
the
problem
is
corrected
.
Theengine
may
be
severely
damaged
.
Oil
pan,
removing
and
installing
(4-cylinder
engines)
1
.
Raise
car
arad
place
securely
ora
jackstands
.
2
.
Remove
splash
shíeld(s)
from
under
engine,
where
ap-
plicable
.
3
.
Drain
engine
oil
as
described
in
020
Maintenance
Pro-
gram
.
4
.
Disconnect
vacuum
hose
adapter
from
vacuum
brake
booster
at
rear
of
engine
compartment
.
5
.
Remove
oil
dipstick
guide
tube
mounting
nut
and
pull
guide
tube
from
oil
pan
.
See
Fig
.
2
.
Page 118 of 759
119-
4
LUBRICATION
SYSTEM
15
.
Remove
oil
pan
screws
.
Lower
andremove
oil
pan
to-
ward
rear
.
Tightening
Torques
"
Control
arm
bushing
carrier
CAUTION-
to
body(M10
bolt)
...............
42
Nm
(31
ft-Ib)
'
lf
the
oil
pan
does
not
separate
easily
from
the
en-
"
Engine
mount
to
gine
cylinder
block,
make
sure
all
mounting
bolis
suspension
crossmember
(M10
nut)
.
42
Nm
(31
ft-Ib)
have
been
removed
.
If
necessary,
a
few
tapswith
"
Front
suspension
crossmember
a
rubber
mallet
shouldbreak
it
free
.
Never
pry
the
to
body
.
.
..
...
..
.
....
See
310
Front
SusPension
oil
pan
loose
.
"
Oil
pan
to
engine
block
(M6
bolt)
8
.8
grade
..
....
.
...
...
.
........
10
Nm
(89
in-lb)
16
.
Installation
is
reverse
of
removal
.
10
.9
grade
...
..
.
....
..
.
.
.
.......
12
Nm
(9
ft-Ib)
"
Thoroughly
clean
all
old
gasket
material
from
mating
"
Power
steering
pump
to
bracket
surfaces
anduse
a
new
gasket
.
(self-locking
nuts)
....
..
.
....
..
.
..
22
Nm
(16
ft-Ib)
"
Applya
small
amount
of
non-hardening
sealer
(3-
"
Power
steering
pump
bracket
to
engine
Bond
O
l209
or
equivalent)
to
oil
pan
gasket
directly
block
or
oil
pan
(self-locking
nuts)
..
.
22
Nm
(16
ft-Ib)
below
joints
for
end
cover
and
front
timing
case
cover
.
"
Stabilizer
bar
link
to
control
arm
See
Fig
.
5
.
M8
nut
.................
...
.
...
22
Nm
(17
ft-Ib)
"
When
installing
oil
pan
to
engine,
tighten
forward
M10
nut
.....................
..
42
Nm
(31
Ib-ft)
screws
first,
then
tightenrear
.
"
Steering
column
universal
joint
"
Fill
engine
with
oil
as
described
in
020
Maintenance
to
steering
rack
spindle
(M8
bolt)
....
19
Nm
(14
ft-ib)
Program
.
0011950
Fig
.
5
.
Joint-mating
areas
at
oil
pan
gasket
where
sealer
should
be
applied
(arrows)
.
Apply
a
bead
3
mm
wideby
2
mm
high
.
OIL
PAN
WARNING
-
Always
use
new
bolis
when
mounting
the
subframe
to
the
body
.
The
one-timeonly
bolis
shouldbe
re-
placed
any
timethey
are
removed
.
NOTE-
The
oil
pickup
is
attached
to
the
oil
pan
using
self-tap-
ping
screws
.
For
this
reasonno
threading
for
the
pickup
is
present
on
new
oil
pans
.
Replace
the
seal
for
the
pickup
and
use
the
oíd
screws
to
rea
ttach
the
pickup
to
the
pan
.
Oil
pan,
removing
and
installing
(6-cylinder
engine,
1992models)
NOTE-
Cars
built
up
to
9/92
(1992models)usea
different
sus-
pension
crossmember
than
later
production
cars
.
Oil
pan
removalprocedureon
the
earlier
cars
requires
that
the
engine
be
raised
and
supportedfrom
above
.
1
.
Raise
car
and
place
securely
on
jackstands
.
2
.
Remove
splash
shield(s)
from
under
engine,
where
ap-
plicable
.
3
.
Drain
engine
oil
as
described
in
020
Maintenance
Pro-
gram
.
4
.
Remove
complete
exhaust
system
.
See180
Exhaust
System
.
5
.
Remove
air
filter
housing
complete
with
mass
air
flow
sensor
.
See
113
Cylinder
Head
Removal
and
Instal-
lation
.
6
.
Remove
alternator
cooling
duct
from
alternator
and
ra-
diator
support
.
7
.
Remove
radiator
cooling
fan
and
fan
shroud
.
Remove
radiator
securing
clips
at
top
of
radiator
.
See
170
Radi-
ator
and
Cooling
System
.
Center
the
steering
spindle
to
the
steering
rack
before
in-
NOTE-
stalling
the
steering
column
shaft
.
See
320
Steering
and
The
radiator
cooling
fan
nut(32
mm
wrench)
has
left
Wheel
Alignment
for
specific
installation
markings
and
pro-
hand
threads
.
cedures
.
Page 119 of 759
8
.
Remove
air
plenum
from
rear
of
engine
compartment
.
See
640
Heating
and
Air
Conditioning
.
9
.
Release
drive
belt
tension
and
remove
alternator
drive
belt
.
Remove
A/C
compressor
drive
belt
.
See
Fig
.
6
.
B11143
Fig
.
6
.
To
remove
poly-ribbed
drive
belt,
pry
cover
from
front
of
ten-
sioner
.
Then
using
8
mm
hex
key,
turntensioner
clockwise
(arrow)
torelease
tension
and
slip
belt
off
pulleys
.
10
.
Unbolt
power
steering
reservoir
and
pull
reservoir
off
engine
mount
bracket
.
11
.
Without
disconnecting
fluid
lines,
remove
power
steer-
ing
bracket
(with
pump)
from
oil
panand
engine
block
.
See
Fig
.
7
.
Disconnect
fluid
lines
from
bracket
on
en-
gine
mount
.
Hang
pump
from
chassis
using
wire
.
12
.
Without
disconnecting
refrigerant
lines,
remove
A/C
compressor
from
engine
block
.
Hang
compressor
from
chassis
using
wire
.
See
640
Heating
and
Air
Condi-
tioning
.
13
.
Remove
oil
dipstick
guide
tube
mounting
bolt
and
re-
move
tube
.
See
Fig
.
8
.
NOTE-
The
guide
tube
is
sealed
in
the
oil
pan
with
an
O-ring
.
Check
that
the
O-ring
comes
out
with
the
tube
.
Use
anew
O-ring
when
installing
the
tube
.
14
.
On
cars
with
automatic
transmission,
remove
brackets
holding
ATF
cooler
linesto
oil
pan
and
cylinder
block
.
LUBRICATION
SYSTEM
119-
5
Fig
.
7
.
Power
steering
pump
mounting
bolts
(arrows)
.
Fig
.
8
.
Oil
dipstick
guide
tube
being
removed
.
Usea
new
O-ring
(arrow)
during
installation
.
15
.
Insta¡¡
engine
lifting
equipment
at
front
engine
lifting
point
and
raise
engine
just
until
its
weight
is
supported
.
16
.
Remove
nuts
at
bottom
of
left
and
right
engine
mounts
.
Remove
ground
wire
from
right
engine
mount
.
1-oosen
nuts
at
top
of
left
and
right
engine
mounts
(do
not
re-
move)
.
OIL
PAN
Page 147 of 759
GENERAL
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.........
130-2
Intake
air
temperature
(IAT)
sensor,
Principles
of
Operatinn
.
.
.
.
.
.
.
.
.
.........
130-2
testing
and
replacing
...
.
...
.
.
.
.......
.
130-19
Basic
Engine
Settings
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
:
.
130-3
Throttle
position
sensor
(TPS),
DISA
(Dual
Resonance
Intake
System)
.
.
.
.
.
130-3
testing
and
replacing
...
.
...
.
.
.
.
.
...
.
.
.130-19
On-Board
Diagnostics
(OBD)
Idle
speed
control
valve,
testing
.
.
.
.
.
.
.
.
.
.
130-20
and
Fault
Diagnosis
.
.
....
.
......
.
.
.
...
130-4
Idle
speed
control
valve,
replacing
.
.
.
.
.
.
..
130-21
SecondaryAir
Injection
.
.
.....
.
.........
.
130-5
BOSCH
DME
M5
.2
COMPONENT
Warnings
and
Cautions
.
.
...
.
.
.
.........
.
130-6
REPLACEMENT
.....
.
......
.
....
.
.
.
..
130-21
ELECTRICAL
CHECKSAND
Mass
air
flow
sensor,
replacing
.
.
....
.
....
130-22
COMPONENT
TESTING
.
.
.
.
.
.
.
.
...
.
.
.
.
.
130-7
Engine
coolant
temperature
(ECT)
Main
sensor,
replacing
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
130-22
rela
y
testing
130
-7
,...
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
Intake
air
temperature
(IAT)
sensor,
Fuel
pump
relay,
testing
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
130-7
rep
lacin
.
.
.
.
.
.
.
.
.
.
.g
.
.
.
.
.
.
.
...
.
.
.
..
.130-22
Oxygen
sensor,
testing
(Boschsystems
only)
130-8
Throttle
poson
sensor
(TPS)
replacing
13022
,
..
.-
FUEL
DELIVERY
TESTS
...
.
....
.
.
.
...
.
130-9
Idle
speed
control
valve,
replacing
...
.
....
.130-23
Operating
fuel
pump
for
tests
.
.
.......
.
...
130-9
SIEMENS
MS
41
.1
COMPONENT
Relieving
fuel
pressure
and
REPLACEMENT
.
...
.
.
.
.
.
.......
.
....
.130-23
connecting
fuel
pressure
gauge
......
.
..
130-10
Residual
fuel
pressure,
testing
.
.....
.
.
.
.
.
130-10
Mass
air
flow
sensor,
replacing
.
.......
.
.
.130-25
Fuel
pressure
regulator
response
Engine
coolant
temperature
(ECT)
to
engine
load,
testing
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
130-11
sensor,
replacing
.....
.
.
.
.
.
.........
.130-25
Fuel
rail
and
injectors,
checking
...
.
.
.
.
.
.
.
130-11
Intake
air
temperature
(IAT)
sensor,
replacing
.
.
.
.
.
.....
.
.
.
.
.
.
.
.......
.
.
.130-25
Fuel
rail
and
injectors,
replacing
..
.
.
.
.
.
.
.
130-12
Throttleposition
sensor
(TPS),
replacing
.
.
.
130-26
Fuel
PressureRegulator
.........
.
.
.
.
.
.
.
130-13
Idle
s
eed
control
valve,
re
lacin
130-26
Fuel
pressure
regulatorreplacing
p
p
g
.'''...
.
'
,
(fuel
rail
mount)
...
.
.
.
.
.
.............
130-13
ECM
PIN
ASSIGNMENTS
.............
.
.
130-26
Fuel
pressure
regulator,
replacing
Engine
control
module
(ECM),
accessing
...
130-26
(undercar
mount)
.
.
.
.
.
.
.
.
.........
.
.
130-14
BOSCH
DME
M1
.7
COMPONENT
TESTS
AND
REPAIRS
.
.
.
.
.
...
.
.
.
.
.
.
.
.
130-14
Air
flow
sensor,
testing
and
replacing
.
.
.
.
.
.
130-14
Engine
coolant
temperature
(ECT)
sensor,
testing
and
replacing
...
.
.
.
.
.
.
.
.
130-15
Throttle
position
sensor
(TPS),
testing
and
replacing
.
..........
.
.....
130-16
Idle
speed
control
valve,
testing
and
replacing
.
.
.
.
.
............
130-16
BOSCH
DME
M3
.1
AND
M33
.1
COMPONENT
TESTS
AND
REPAIRS
.
.
.
130-17
Mass
Air
Flow
Sensor
.
.
.
.
.
.
.
.
.....
.
.
.
.
.130-17
Mass
air
flow
sensor
(hotwire),testing
and
replacing
.
.
.
.
.
.....
.
.
.
.
.
.
.
130-17
Mass
air
flow
sensor
(hot
film),
testíng
and
replacing
.
.
.
.....
.
.
.
.
.
.
.
.
.
130-18
Engine
coolant
temperature
(ECT)
sensor,
testing
and
replacing
..
.
.
.
.
.
...
.
130-18
130
Fuel
i
n
jection
FUEL
INJECTION
130-1
TABLES
a
.
Engine
Management
System
Variants
.........
.130-2
b
.
Mass
Air
Flow
Sensor
Variants
..
.
..
..........
.130-2
c
.
Fuel
Pressure
Specifications
..
.
.
...
..........
130-11
d
.
Engine
Coolant
Temperature
Sensor
or
Intake
Air
Temperature
Sensor
Test
Values
(DME
1
.7)
...
.
130-15
e
.
ThrottlePosition
Sensor
Tests
(DME
1
.7)
......
.130-16
f
.
Engine
Coolant
Temperature
Sensor
or
Intake
Air
Temperature
Sensor
Test
Values
(DME
3
.1/3
.3
.1)130-19
g
.
Throttle
Position
Sensor
Tests
(DME
3
.1/3.3
.1)
.
.130-20
h
.
ECM
Pin
Assignment-Bosch
DME
M1
.7
....
.
..
.130-28
i.
ECM
Pin
Assignment-Bosch
DME
M3
.1
.......
.130-30
j
.
ECM
Pin
Assignment-Bosch
DME
M3
.3
.1
.....
.130-32
k
.
ECM
Pin
Assignment-Bosch
DME
M5
.2
.......
.
130-34
I.
ECM
Pin
Assignment-Siemens
DME
MS
41
.1
..
.
130-36
Page 148 of 759
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
.
Page 151 of 759
The
fuel
injection
systems
used
on
the
1996
and
later
cars
covered
bythis
manual
are
OBD
II
compliant
.
This
system
is
in-
corporated
into
both
the
Bosch
M5
.2
(M44
engine)
and
the
Si-
emens
MS
41
.1
(M52/S52US
engine)
engine
management
systems
.
OBD
II
systems
use
sophisticateddiagnostic
soft-
ware
capable
of
recognizing
and
electronically
storing
hun-
dreds
of
DTCs
in
the
system
ECM
.
DTCs
can
only
be
accessed
using
special
scan
tooltest
equipment
.
The
BMW
dealer
is
equipped
with
the
specialized
OBD
II
scan
toolto
quickly
and
efficiently
locate
engine
management
problems
.
Alternately,
a
"generic"
scan
tool
can
be
used
to
access
OBD
II
fault
informa-
tion
.
NOTE-
"
At
the
time
this
manual
went
to
press,
generic
scan
tools
were
notwidely
available
for
BMW
vehicles
.
The
generic
sean
tool
is
a
specialized
toolthat
plugs
into
a
standardized
OBD
11
connector
on
1996
and
later
pas-senger
vehícles
built
for
sale
in
the
US
.
"
The
OBD
11
fault
memory
(including
an
illuminated
Check
Engine
light)
can
only
be
reset
using
the
spe-
cial
scan
tool
.
Removing
the
connector
trom
the
ECM
or
disconnecting
the
battery
will
not
erase
the
fault
memory
.
"
The
16-pin
OBD
11
diagnostic
connector
is
located
on
the
lower
left
dash
panel
.
Refer
to
Fig
.
1
.
6
1
.
Secondary
air
pump
2
.
Electric
solenoid
valve
3
.
One-way
check
valve
4
.
Intake
manifold
5
.
Exhaust
manifolds
6
.
Secondary
air
check-valve
®
G~
i
o
o
0
0
G
0000
o
,-
00
~
1111111
in
,,
0
1--
a
Fig
.
5
.
Components
of
6-cylinder
secondary
air
injection
system
.
4-
cylinder
system
is
similar
.
Secondary
AirInjection
FUEL
INJECTION
130-
5
All
OBD
II
6-cylinder
engines
are
equípped
with
asecond-
ary
air
injection
system
.
In
addition,
beginning
in
January
1997,
the
M44
engine
was
classified
as
a
TLEV
(Transitional
Low
Emission
Vehicle)
engine
and
is
also
equipped
with
sec-
ondary
air
injection
.
Typical
components
of
the
secondary
air
injection
system
are
depicted
in
Fig
.
5
.
Secondary
air
injection
usesan
electric
pump
to
pump
fresh
air
finto
the
exhaust
systemupstream
of
the
catalytic
converter
during
engine
warm-up
.
By
providing
extra
oxygen
to
the
un-
burned
fuel
in
the
exhaust,
hydrocarbons
oxidize
and
carbon
monoxide
combines
with
oxygen
to
form
carbon
dioxide
andwa-
ter
.
The
air
injection
pump
stops
within
a
specified
timed
intenral
.
4
0013120
GENERAL
Page 154 of 759
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
.
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