ignition
Table
b
.
Engine
Management
Systems
engine
has
high
mileage
.
Engine
1
System
4-cylinder
engines
M42
(1992-1995)
Bosch
DME
Ml
.7
M44
(1996-1998)
Bosch
DME
M5
.2
(OBD
II)
6-cylinder
engines
M50
(1992)
Bosch
DME
M3
.1
M50
VANOS
(1993-1995)
Bosch
DME
M3
.3
.1
M52
(1996-1998)
Siemens
MS41
.1
(OBD
II)
S50US
(1995)
Bosch
DME
M3
.3
.1
S52US
(1996-1998)
Siemens
MS41
.1
(OBD
II)
Both
the
4-cylinder
and
6-cylinder
engines
use
a
distributor-
less
ignition
system
with
individual
ignition
coils
for
each
cylin-
der
.
FuelDelivery
Pressurized
fuel
from
the
in-tank
fuel
pump
is
injected
via
solenoid-type
fuel
injectors
.
The
ECM
controls
the
opening
and
closing
of
the
injectors
by
switchingthe
ground
side
of
each
injector
circuit
.
The
exact
amount
of
fuel
injected
is
de-
termined
by
the
amount
of
timethe
injectors
are
open
.
Cooling
System
Whenever
the
engine
is
running,
acoolant
pump
circulates
coolant
through
the
engine
and,
if
either
heater
control
valves
are
open,
through
the
heater
core
in
the
passenger
compart-
ment
.
The
coolant
absorbs
excess
heat
and
carries
it
to
the
ra-
diator
where
it
is
transferred
into
the
passing
airstream
.
A
thermostat
controls
the
flow
of
coolant
through
the
radiator
based
on
engine
temperature
.
Lubrication
System
The
lubrication
system
is
pressurized
whenever
theengine
is
running
.
The
oil
pump
draws
oil
through
a
pickup
in
the
bot-
tom
of
the
oil
pan,thenforces
it
through
a
replaceable
oil
filter
and
finto
the
engine
oíi
passages
.
On
4-cylinder
engines,
the
oil
pump
is
mounted
to
the
front
engine
cover
.
On
6-cylinder
engines,thechain-driven
oil
pump
is
bolted
to
the
bottom
of
the
cylinder
block
.
A
pressure
relief
valve
limits
the
maximum
system
pres-
sure
.
A
bypass
valve
prevents
the
oil
filter
from
bursting
and
insures
engine
lubrication
should
the
filter
become
plugged
.
See
119
Lubrication
System
for
additional
information
.
ENGINE-GENERAL
100-
5
Various
versions
of
DME
systems
are
usedon
thecars
cov-
MECHANICAL
TROUBLESHOOTING
ered
by
this
manual
.
See
Table
b
.
Each
system
is
highly
adaptive
to
compensate
for
things
suchasengine
wear
and
When
troubleshooting
an
engine
that
fails
to
start
or
runs
vacuum
leaks
.
poorly,
first
check
its
mechanical
condition-particularly
if
the
Warnings
and
Cautions
For
personal
safety,
as
well
asthe
protection
of
sensitive
electronic
components,
the
following
warnings
and
cautions
must
be
adhered
to
during
all
troubleshooting,
maintenance,
and
repairwork
.
WARNING
-
"
The
ignition
system
produces
high
voltages
that
can
be
fatal
.
Avoid
contact
with
exposed
termi-
nals
anduse
extreme
caution
when
working
on
a
car
with
the
ignition
switched
on
or
the
engine
running
.
"
Do
not
touch
or
disconnect
any
high
voltage
ca-
bles
from
the
coil,
distributor,
orspark
plugs
while
the
engine
is
running
or
being
cranked
by
the
starter
"
Connect
and
disconnect
the
engine
manage-
ment
system
wiring
and
test
equipment
leads
only
when
the
ignition
is
switched
off
.
"
Gasoline
is
highly
flammable
and
its
vapors
are
explosive
.
Do
not
smoke
or
work
on
a
car
near
heaters
or
other
fire
hazards
when
diagnosing
and
repairing
fuel
system
problems
.
Have
a
fire
extínguisher
available
in
case
of
an
emergency
.
"
Disconnecting
the
battery
may
erase
fault
code(s)
stored
in
control
module
memory
.
Using
special
BMW
diagnosnnc
equipment,
check
for
fault
codes
prior
to
disconnecting
the
battery
cables
.
If
the
Check
Engine
lightis
illuminated,
see
On-
Board
Diagnostics
(OBD)
forfault
code
infor-
mation
.
If
any
other
system
faults
havebeen
de-tected
(indicated
byan
illuminated
warning
light),
see
an
authorized
BMW
dealer
.
CAUTION-
"
Prior
to
disconnecting
the
battery,
read
the
bat-
tery
disconnection
cautions
gíven
at
the
front
of
this
manual
on
page
viii
.
"
Do
notconnect
any
test
equipment
that
delivers
a
12-volt
power
supply
to
terminal15
(+)
of
the
ignition
coil
.
The
current
flow
may
damage
the
ECM
.
In
general,
connect
test
equipment
only
as
specified
by
BMW,
this
manual,
or
the
equip-
ment
maker
.
"
Do
not
disconnect
the
battery
with
the
engine
running
.
Do
notrunthe
engine
with
any
of
the
sparkplug
wires
disconnected
.
MECHANICAL
TROUBLESHOOTING
100-8
ENGINE-GENERAL
Symptom
1
Probable
cause
and
correctiveaction
1
.
Engine
will
not
start
or
run
.
Starter
cranks
a
.
No
fuel
reaching
engine
.
Check
forfuelin
tank
.
engine
at
normal
speed
.
Fuel
pump
notoperating
.
Repair
Group
160
b
.
No
spark
.
Check
ignition
system
.
Repair
Group
120
c
.
Incorrect
valve
timing
.
Check
timing
chain
.
Repair
Group
117
2
.
Check
Engine
warning
light
illuminated
.
a
.
DME
engine
management
system
self-diagnostic
fault
detected
.
Sea
an
authorized
BMW
dealer
or
other
qualified
shop
for
OBD
II
fault
code
diagnosis
.
See
also
On-
board
Diagnostics(OBD),
given
later
inthis
repair
group
.
3
.
White
exhaust
smoke
(steam)
.
a
.
Failed
cylinder
head
gasket
(probably
accompanied
bylowcompression
readings)
.
Replace
gasket
and
resurface
cylinder
head
if
necessary
.
Repair
Group
113
4
.
Blue-gray
exhaust
smoke
and
oily
spark
a
.
Contaminated
or
gasoline-diluted
engine
oil
.
Change
engine
oil
and
replace
oil
filter
.
plugs
.
Indicates
oii
burning
in
combustion
.
Repair
Group
020
b
.
Faulty
valve
guide
seals
or
valve
guides
.
Replace
valve
guide
oil
seals
or
overhaul
cylinder
head
.
Repair
Group
116
5
.
Pinging
or
rattling
when
under
load,
a
.
Ignition
timing
too
advanced
.
Ignition
knocksensors
faulty
(CheckEngine
light
traveling
uphill,
or
accelerating,
especially
illuminated)
.
Repair
Group
120fromlow
speeds
.
Indicates
pre-ignition
or
b
.
Fuel
octane
leve¡
toolow
.
detonation
.
c
.
Engine
running
too
hot
or
overheating
.
Check
cooling
system
.
Repair
Group
170
6
.
Light
metallic
tapping
that
varies
directly
with
engine
speed
.
Oil
pressure
warning
light
not
illuminated
.
7
.
Light
metallic
knock
that
varies
directly
with
enginespeed
.
Oil
pressure
warning
light
blinking
or
fully
illuminated
;
may
be
most
noticeable
during
hard
stops
or
cornering
.
8
.
Screeching
or
squealing
under
load
that
a
.
Loose,worn,
or
damaged
drive
belt
.
Inspect
belt(s)
.
Repair
Group
020
goesaway
when
coasting
.
9
.
Growling
or
rumbling
that
varieswith
engine
a
.
Remove
drive
belt(s)toidentifyfaulty
component
.
Check
for
play,
bearing
roughness,
rpm
.
Indicates
abad
bearing
or
bushing
in
and
loose
mountings
.
Refer
to
appropriate
repair
group
for
repair
procedures
.
an
engine-driven
accessory
.
DRIVEABILITY
TROUBLESHOOTING
On-Board
Diagnostics
(OBD)
On-Board
Diagnostics
is
incorporated
into
al¡
engine
man-
Two
generations
of
OBD
are
usedon
thecars
covered
by
agement
systems
used
on
the
cars
covered
by
this
manual
.
this
manual
:
Therefore,
checking
for
fault
codes
should
be
the
first
step
in
troubleshootinga
driveability
problem
.
For
additional
informa-
On-Board
Diagnostics
tion
on
engine
management
and
repair
see130
Fuel
Injec-
tion
.
"
1992-1995models
....
.
..
....
.
..
.......
OBD
I
"
1996-1998models
.
....
..
.
.
.
..
.
........
OBD
II
DRIVEABILITY
TROUBLESHOOTING
Tablec
.
Engine
Mechanical
Troubleshooting
b
.
Warped
or
cracked
cylinder
head
.
Resurface
or
replace
cylinder
head
.
Repair
Group
113
c
.
Cracked
cylinder
block
.
Replace
engine
or
short
block
.
c
.
Worn
piston
rings
.
Overhaul
or
replace
engine
.
d
.
Failed
cylinder
head
gasket
.
Replace
gasket
.
Repair
Group
113
d
.
Air/fuel
mixture
too
lean
(Check
Engine
light
illuminated)
.
Repair
Group
130
a
.
Valveclearances
excessive
.
Check
hydraulic
valve
adjusters
.
Repair
Group
116
b
.
Low
oil
pressure
orpossibly
defective
warning
light
circuit
.
Check
oil
pressure
andwarning
light
circuit
.
Repair
Group
119
c
.
Dirty
oil
.
Change
oil
.
Repair
Group
020
.
a
.
Low
oil
leve¡
.
Check
and
correct
oil
leve¡
.
b
.
Low
oil
pressure/worn
or
faulty
oil
pump
.
Oil
pump
pickup
restricted/clogged
.
Check
oil
pressure
.
Repair
Group
119
The
OBD
system
detects
emissions-related
engine
manage-
ment
malfunctions
and
tucos
on
the
Check
Engíne
lightin
the
in-
strument
cluster
.
TheCheck
Engine
light
will
stay
on
until
the
code(s)are
called
up
and
the
memory
is
erased
.
When
faulty
are
detected,
the
OBD
system
stores
a
Diagnostic
Trouble
Code
(DTC)
in
the
system
ECM
.
In
addition,
the
Check
Engine
warn-
ing
light
will
come
on
if
an
emissions-related
fault
is
detected
.
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
.
119-
6
LUBRICATION
SYSTEM
17
.
Raise
engine
as
much
as
possible
.
Check
carefully
for
22
.
Installation
is
reverse
of
removal
.
obstructions,
wiring
harness
clearance
and
pinched
hoses
or
lines
as
engine
is
raised
.
"
When
installing
oil
pan,
apply
a
b
d
of
non-hardening
sealing
compound
(3-Bond
1209
0
or
equivalent)
to
18
.
Remove
oil
pan
mounting
bolts
and
lower
oil
pan
to
front
and
rear
end
cover
seam
areas
on
block
.
subframe
crossmember
.
"
Position
oil
pump
pickup
tube
and
oil
pan
onto
block
and
install
pickup
tube
using
a
new
gasket
.
"
Be
sure
tab
on
gasket
faces
down
towards
intake
of
NOTE-
pickup
tube
.
If
the
oil
pan
does
not
separate
easily
from
the
engine
"
Tightenforward
oil
pan
screws
first,
then
tighten
rear
.
cylinder
block,
afew
taps
with
arubber
mallet
should
"
Fill
engine
with
oil
as
described
in
020
Maintenance
break
it
free
.
Do
not
pry
the
oil
pan
loose
.
Program
.
"
After
adding
engine
oil,
start
and
run
engine
.
Raise
en-
19
.
Remove
oil
pump
sprocket
mounting
nut
.
See
Fig
.
9
.
gine
speed
to
2,500
rpm
until
oil
pressure
warning
Lift
sprocket
off
together
with
drive
chain
.
lampgoes
out(about
5seconds)
.
Fig
.
9
.
Oil
pump
sprocket
mounting
nut
(left-hand
thread)
on
6-cylin-
OII
pan,
removing
and
installing
derengine(arrow)
.
(6-cylinder
engine,
1993
and
later
modeis)
NOTE-
The
oíl
pump
sprocket
nut
has
left
hand
threads
.
20
.
Unbolt
oil
pump
pickup
tubefrom
oil
pump
.
Unbolt
oil
pump
from
engine
block
.
See
Oil
pump,
removing
and
installing
(6-cylinder
engine)
.
21
.
Remove
oil
pan
from
rear
.
Tightening
Torques
"
Engine
mount
to
suspension
crossmember(M10
nut)
..
42
Nm
(31
ft-Ib)
"
Oil
pan
to
engine
block
(M6
bolt)
8
.8
grade
....
..
.
...
...
.
........
10
Nm
(89
in-lb)
10
.9
grade
.
.
..
.
..
...
.
.
.
.
.
.....
12
Nm
(106
in-lb)
"
Oil
pump
to
engine
block
.
...
...
.
..
22
Nm
(16
ft-Ib)
"
Oil
pump
sprocket
to
oil
pump
shaft
(M1
0x1
left-hand
thread)
...
..
.
.
..
.
25
Nm
(18
ft-Ib)
"
Power
steering
pump
to
bracket
(self-locking
nuts)
.....
.
....
..
.
...
22
Nm
(16
ft-lb)
"
Power
steering
pump
bracket
to
engine
block
or
oil
pan
(self-locking
nuts)
.
..
22
Nm
(16
ft-Ib)
NOTE-
Cars
built
after
9/92
use
a
different
suspension
cross-
member
¡han
earfier
productíon
cars
.
Oil
pan
removal
procedure
on
the
later
cars
requíres
that
the
engine
be
supported
from
aboye
and
the
front
suspension
cross-
member
be
unbolted
and
loweredfrom
the
chassis
.
1
.
Raisecar
and
place
securely
on
jackstands
.
2
.
Remove
splash
shield
fromunder
engine,
if
applicable
.
3
.
Drain
engine
oil
as
descríbed
in
020
Maintenance
Pro-
gram
.
4
.
Remove
alternator
cooling
duct
from
alternator
and
ra-
diator
support
.
119-
1
0
LUBRICATION
SYSTEM
Oil
pump,
removing
and
installing
(6-cylinder
engine)
Oil
pressure
on
the
6-cylinder
engines
is
generated
by
a
gear-type
pump
bolted
to
the
bottom
of
the
engine
block
.
The
oil
pump
is
chain
driven
off
the
front
of
the
crankshaft
.
NOTE-
Oil
pump
removal
requires
raising
the
engine
(cars
built
up
to
9-92)
or
lowering
the
front
suspension
crossmem-
ber
(cars
built
from
9-92)
to
remove
the
oil
pan
.
1.
Drain
oil
as
described
in
020
Maintenance
Program
.
2
.
Remove
oil
pan
as
described
earlier
.
3
.
Remove
oil
pump
sprocket
mounting
nut
(left-hand
thread)
.
See
Fig
.
16
.
Lift
sprocket
off
together
with
drive
chain
.
Fig
.
16
.
Oil
pump
sprocket
mounting
nut
(left-hand
thread)
on
6-cylin-
der
engine
(arrow)
.
4
.
Remove
mounting
bolts
from
oil
pump
and
oil
pump
pickup
tube
.
Withdraw
pump
.
NOTE-
Note
any
spacers
between
pump
and
engine
block
.
See
Fig
.
17
.
"
Note
position
of
locating
dowels
.
OIL
PUMP
811186
0011952
Fig
.
17
.
Oil
pump
mounting
points
(1)
and
pickup
tube
mountíng
points
(2)
.
5
.
Remove
coverfrom
oil
pump
and
check
for
wear
or
scoring
.
Spin
oil
pump
shaft
and
check
that
gears
turn
smoothly
.
Replace
pump
if
gears
spinwith
difficulty
or
any
wear
is
present
.
6
.
Installation
is
reverse
of
removal,
noting
the
following
:
"
Align
sprocket
splines
to
oil
pump
shaft
splines
before
tightening
sprocket
nut
.
Tightening
Torques
"
Oil
pump
to
engine
block
(M8)
......
22
Nm
(16
ft-Ib)
"
Oil
pan
to
engine
block
(M6
bolt)
8
.8
grade
..
...
.
...
...
.
.........
10
Nm
(89
in-lb)
10
.9
grade
.
...
.
..
....
.
........
12
Nm
(106
in-lb)
"
Oil
pump
sprocket
to
oil
pump
shaft
(M1
0x1
left-hand
thread)
..........
25
Nm
(18
ft-Ib)