Coil BMW 325i 1994 E36 User Guide
Page 76 of 759
113-10
CYLINDER
HEAD
REMOVAL
AND
INSTALLATION
Tightening
Torques
"
Coolant
drain
plug
to
cylinder
block
.
.
25
Nm
(18
ft-1b)
"
Intake
manifold
support
to
manifold
.
.
15
Nm
(11
ft-Ib)
"
Lower
intake
manifold
to
cylinder
head
.
..........
.
..
...
15
Nm
(11
ft-Ib)
"
Lower
intake
manifold
to
upper
manifold
..........
.
..
...
15
Nm
(11
ft-Ib)
"
Radiator
cooling
fan
to
coolant
pump
.
40
Nm
(30
ft-Ib)
"
Radiator
drain
screw
to
radiator
...
.
2
.5
Nm
(22
in-lb)
CYLINDER
HEAD,
6-CYLINDER
For
ease
of
use
this
procedure
is
broken
into
subsections,
as
follows
:
General
Coolingsystem,
draining
Cyiinder
head
cover,
removing
Intake
manifold,
removing
Timing
chains,
uncoupling
Cylinder
head
assembly,
removing
WARNING
-
Allow
the
engine
to
cool
before
beginning
this
pro-
cedure
.
General
1
.
Working
inside
luggage
compartment,
disconnect
neg-
ative
(-)
battery
cable
.
CAUTION-
"
Prior
to
disconnectiog
the
battery,
read
the
bat-
tery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
vi¡¡
.
"
Disconnecting
the
battery
may
erase
fault
code(s)
stored
in
control
module
memory
.
Check
for
fault
codes
using
special
BMW
diagnostic
equipment
2
.
Remove
front
exhaust
pipes
from
manifolds
.
Discard
nuts
.
3
.
Remove
air
filter
housing
complete
with
mass
air
flow
sensor
and
intake
air
ducting
.
Disconnect
vacuum
hos-
es
from
throttle
housing
.
4
.
On
M52
and
S52US
engines
:
Remove
secondary
air
injection
check-valve
from
front
of
engine
and
set
aside
.
CYLINDER
HEAD,
6-CYLINDER
Coolingsystem,
draining
5
.
Drain
engine
coolant
and
Rmove
coolant
hoses
from
thermostat
housing
.
Drain
engine
block
by
removing
block
drain
.
See
170
Radiator
and
Cooling
System
.
NOTE-
The
block
drain
is
on
the
exhaust
side
of
the
engine,
near
cylinder
no
.
5
.
6
.
Remove
radiator
cooling
fan
and
fan
shroud
.
See
170
Radiator
and
Cooling
System
.
NOTE-
The
radiator
cooling
fannut(32
mm
wrench)
has
left-
hand
threads
.
Cylinder
head,
removing
(6-cylinder
engine)
7
.
Disconnect
heater
hoses
at
rear
of
cylinder
head
.
See
Fig
.
26
.
'i
8
.
Remove
alternator
cooling
duct
.
Cylinder
head
cover,
removing
0012687
Fig
.
26
.
Disconnect
heater
hoses
at
heater
valve
(A)
and
heater
core
(B)
.
9
.
Remove
air
plenum
from
rear
of
engine
compartment
.
See640
Heating
and
Air
Conditioning
.
10
.
Remove
plastic
cylinder
head
covers
from
above
fuel
injectors
and
ignition
coils
.
Pull
larger
cover
forward
when
removing
.
See
Fig
.
27
.
11
.
Disconnect
crankcase
ventílation
hose
fitting
from
cyl-
inder
head
cover
.
12
.
Disconnect
ignition
coil
harness
connectors
from
coiis
.
Remove
ignition
coiis
and
spark
plugs
.
See
120
Igni-
tion
System
.
Page 77 of 759
Fig
.
27
.
Remove
top
enginecovers
by
prying
out
plugs
and
removing
nuts
(A)
.
Make
sure
rubber
insulators
on
either
side
of
large
cover
do
not
fall
off
during
cover
removal
(B)
.
Fig
.
28
.
Fuel
injection
harness
beíng
lifted
off
engine
to
be
placed
at
base
of
windshield
(A)
.
Ignitioncoils
are
also
visible
(B)
.
M50
engine
shown,
other
6-cylinder
engines
are
similar
.
14
.
Remove
cylinder
head
cover
mounting
bolts
and
re-
move
cylinder
head
cover
.
CYLINDER
HEAD
REMOVAL
AND
INSTALLATION
113-
11
15
.
Remove
oil
baffle
cover
from
above
intake
camshaft
.
See
Fig
.
29
.
Fig
.
29
.
Camshaft
oil
baffle
coverbeing
removed
.
NOTE-
The
cylinder
head
cover
mounting
bolt
insulators
and
13
.
Remove
hold
down
nuts/bolts
from
fuel
injection
har-
gaskets
should
be
reinstalled
in
the
same
order
.
Make
ness
.
Pry
back
injector
connector
retaining
clips
and
lift
note
of
their
arrangement
during
removal
.
entire
harness
off
engine
.
See
Fig
.
28
.
Intake
manifold,
removing
811119
16
.
Disconnect
vacuum
hose
from
brake
system
vacuum
booster
.
Plug
opening
in
booster
.
17
.
Remove
throttle
housing
mounting
bolts
and
remove
throttle
housing
.
Set
throttle
housing
aside
without
dis-
connecting
cablesor
coolant
hoses
.
See
Fig
.
30
.
Fig
.
30
.
Remove
4
comer
bolts
(arrows)
from
throttle
housing
and
unbolt
complete
assembly
from
intake
manifold
.
Remove
complete
throttle
assembly
without
disconnecting
connec-
tors,
hoses
or
cables
.
(M50
engine
shown
.)
CYLINDER
HEAD,
6-CYLINDER
Page 84 of 759
113-
1
8
CYLINDER
HEAD
REMOVAL
AND
INSTALLATION
CYLINDER
HEAD,
6-CYLINDER
Fig
.
46
.
Primary
chaintensioner
being
installed
.
Piston
cutout
must
engage
chain
rail
.
22
.
Install
intake
cam
cover
and
then
install
cylinder
head
cover
.
Check
for
correct
seating
of
half-moons
in
back
of
cylinder
head
cover
.
Use
a
small
amount
of
3-Bond
O
1209
orequivalent
seaiant
at
corners
of
half-moon
cut-
outs
.
23
.
Install
front
exhaust
pipes
to
manifolds
using
new
gas-
kets
and
nuts
.
Coat
manifold
studs
with
copper
paste
prior
to
installing
nuts
.
24
.
Installationof
remaining
parts
is
reverse
of
removal
.
Refill
cooling
system
as
described
in
170
Radiator
and
Cooling
System
.
Change
engine
oil
and
filter
as
de
scribed
in
020
Maintenance
Program
.
Check
adjust-
ment
of
accelerator
cable
.
Additional
tightening
torques
are
given
below
.
Reconnect
battery
last
.
25
.
Installationof
remaining
parts
is
reverse
of
removal,
noting
the
following
:
"
Make
sure
all
sealing
surfaces
are
clean
and
free
of
old
gasket
material
.
Insta¡¡
new
intake
manifold
gasket
.
"
Reinstall
harness
connectors
for
oil
pressure
switch
and
coolant
temperature
sensor
before
installing
in-
take
manifold
.
"
Refill
cooling
systemas
described
in
170
Radiator
and
Cooling
System
.
"
Change
engine
oil
and
filter
as
described
in
020
Main-
tenance
Program
.
"
If
necessary,
adjust
accelerator
cable
.
"
Reconnect
battery
last
.
CAUTION-
To
prevent
damaging
engine
electronic
systems,
be
sure
to
install
all
ground
wirespreviously
re-
moved,
including
the
ground
wires
at
the
cylinder
head
for
the
ignition
coils
.
Tightening
Torque
Tightening
Torques
"
Cylinder
head
cover
"
Coglant
drain
plug
to
cylinder
block
.
.
25
Nm
(18
ft-Ib)
to
cylinder
head(M6
screws)
.
.
.....
10
Nm
(89
in-lb)
"
Intake
manifold
to
cylinder
head
.
...
.
15
Nm
(11
ft-Ib)
"
Radiator
cooling
fan
to
coolant
pump
.
40
Nm
(30
ft-Ib)
"
Radiator
drain
screw
to
radiator
.
..
2
.5
Nm
(22
in-lb)
Page 93 of 759
5
.
Pull
hydraulic
valve
adjuster
straight
out
of
cylinder
head
.
See
Fig
.
13
.
Fig
.
13
.
Remove
hydraulic
valve
adjuster
by
pulling
straight
out
ofcyl-
inder
head
(arrow)
.
6
.
Installation
is
reverse
of
removal
.
Be
sure
to
inspect
HVA
bore
in
the
cylinder
head
for
wear
or
scoring
.
Tightening
Torque
"
Cylinder
head
cover
to
cylinder
head/timing
chain
cover
M6
bolt
.........
..
..
...
........
10
Nm
(89
in-lb)
M7
bolt
.......
.
.
..
...
.
...
.
.....
15
Nm
(11
ft-Ib)
Hydraulic
cam
followers,
checking
and
replacing
(M42
and
al¡
6-cylinder
engines)
The
M42
engine
and
al¡
6-cylinder
engines
use
self-adjust-
ing
hydraulic
cam
followers
to
keep
the
valveclearances
with-
ina
limited
working
range
.
The
cam
followers
are
sealed
units
and
require
no
maintenance
.
See
Fig
.
14
.
.
Under
some
circumstances,
suchasa
cold
start,
the
cam
followers
may
become
noisy
.
Hydraulic
cam
follower
noise
is
usually
a
high-pitched
tapping
or
chattering
noise
.
In
most
in-
stances,
this
is
considered
normalas
long
as
the
noise
goes
away
in
a
fewminutes
(maximum
20
minutes)
.
lf
the
noise
does
not
go
away,
either
the
follower
is
faulty
or
the
oil
pres-
sure
to
the
follower
is
low
.
Hydraulic
cam
follower
replace-
ment
requires
that
the
camshaft
first
be
removed
.
NOTE-
Before
checking
valve
adjusters,
make
sure
engine
oil
ís
fresh
and
at
proper
level
.
CYLINDER
HEAD
AND
VALVETRAIN
116-
9
Fig
.
14
.
Section
view
of
camshaft
(A),
hydraulic
cam
follower
(B),
and
valvewith
conical
valvespring
(C)
usedon
M52
engine
.
1.
Run
engine
until
it
reachesnormal
operating
tempera-
ture
.
2
.
Turn
engine
off
and
remove
top
engine
covers,
ignition
coils,
and
cylinder
head
covers
.
See
113
Cylinder
Head
Removal
and
Installation
.
3
.
Use
a
plastic
or
wooden
stickto
press
down
on
top
of
cam
follower
.
See
Fig
.
15
.
If
there
is
any
noticeable
clearance,
the
follower
is
faulty
and
should
be
replaced
.
811107
Fig
.
15
.
Hydraulic
cam
follower
in
M52
enginebeing
checked
.
Note
that
camshaft
lobe
is
pointing
up
.
CYLINDER
HEAD
AND
VALVETRAIN,
RECONDITIONING
Page 110 of 759
117-
1
4
CAMSHAFT
TIMING
CHAIN
22
.
Installation
of
remaining
parts
is
reverse
of
removal,
When
theengine
is
running,
the
piston
housing
is
supplied
noting
the
following
:
with
pressurized
engine
oil
.
At
idie,
the
solenoid
isin
the
off
"
When
installing
thermostat,
make
sure
arrow
or
vent
position
(de-energized)
and
valve
timing
is
maintained
in
the
hole
faces
up,
if
applicable
.
normal
position
:
When
the
solenoid
is
energized,
the
gear
cup
"
Refill
cooling
systemas
described
in
170
Radiator
piston
moves
forward
to
advance
the
camshaftby
a
maximum
and
Coming
System
.
of
12
.5
.
"
Install
oil
pan
as
described
in
119
Lubrication
Sys-
tem
.
"
Fill
engine
with
oil
and
install
a
new
oil
filter
as
de-
scribed
in
020
Maintenance
Program
.
"
Insta¡¡
ground
wires
at
cylinder
head
cover
mounting
studs
and
at
front
of
cylinder
head
and
thermostat
housing,
where
applicable
.
VANOS
system
operation,
testing
Tightening
Torques
There
are3
special
tools
required
to
check
VANOS
opera-
"
Coolant
drain
plugto
cylinder
block
.
.
25
Nm
(18
ft-Ib)
tion
;
an
electricaltest
lead
(BMW
special
tool
no
.
12
6
410),
an
"
Radiator
cooling
fan
to
coolant
pump
.
40
Nm
(30
ft-Ib)
air
line
fitting
(BMW
special
tool
no
.
11
3
450),
and
a
crank-
"
Radiator
drain
screw
to
radiator
...
.
2
.5
Nm
(22
in-Ib)
shaft
TDC
locking
tool
(BMW
special
tool
no
.
112
300)
.
"
Upper
timing
chaincover
to
cylinder
head
The
test
leal
is
used
to
power
the
solenoid,
simulating
the
M6
nut
...
.....
.............
..
.
10
Nm
(89
in-lb)
ground
signal
from
the
DME
control
unit
.
The
air
line
fitting
M8
bolt
.....
....
.
.
.............
22
Nm
(17
ft-Ib)
takes
the
place
of
the
oil
supply
line
fitting
to
simulate
oil
Ares-
"
VANOS
control
unit
to
cylinder
head
sure
.
The
locking
tool
positions
and
locks
the
crankshaft
at
M6
nut
.........
..
..
.
..........
10
Nm
(89
in-lb)
TDC,
cylinder
no
.
l.
M8
bolt
........
...
.............
22
Nm
(17
ft-Ib)
"
VANOS
oil
supply
pipe
to
VANOS
control
unit
1
.
Remove
alternator
cooling
air
duct
.
banjo
bolt
.......
..
..
.
..........
32
Nm
(24
ft-Ib)
VANOS
(VARIABLE
VALVE
TIMING)
3
.
Remove
top
plastic
enginecovers
.
Disconnect
ignition
coil
harness
connectors
fromcofs
.
Remove
ignition
1993
and
later
6-cylinder
engines
are
equipped
with
a
vari-
coils
.
able
valve
timing
system
called
VANOS
.
This
system
is
con-
trolled
by
the
engine
management
system
and
dynamically
4
.
Remove
cylinder
head
cover
mounting
bolts
and
re-
adjusts
intake
camshaft
timing
based
on
engine
load,
engine
move
cylinder
head
cover
.
Unclip
andremove
oil
baffle
speed
and
engine
temperature
.
cover
from
above
intake
camshaft
.
See
113
Cylinder
Head
Removal
and
installation
.
The
main
components
of
the
VANOS
system
are
the
control
unit
with
piston
housing
and
integral
spool
valve,
and
the
mod-
ified
intake
camshaft
.
See
Fig
.
35
.
VANOS
(VARIABLE
VA
LVE
TIMING)
Fig
.
35
.
VANOS
control
unit
with
modified
intake
camshaft
.
B11001
WARNING
-
Special
BMW
service
tools
are
required
to
check
and
repair
the
VANOS
System
.
Read
theproce-
dures
through
before
beginning
the
job
.
2
.
Disconnect
crankcase
ventilation
hose
fitting
from
cyl-
inder
head
cover
.
NOTE-
Note
the
arrangement
of
the
cylinder
head
cover
bolt
insulators
and
gaskets
during
removal
.
5
.
Set
engine
to
approximate
TDC
by
rotating
in
normal
operating
direction
until
camshaft
lobes
at
cylinder
no
.
1
are
facing
each
other
.
See
Fig
.
20
.
6
.
Set
engine
to
TDC
by
aligning
"0/T"
mark
(0°TDC)on
front
vibration
damper
withcast
boss
on
lower
timing
chain
cover
.
See
Fig
.
21
.
7
.
Lock
crankshaft
in
position
by
inserting
BMW
special
tool
no
.
11
2
300
through
transmission
bellhousing
and
into
hole
in
flywheelor
driveplate
.
See
Fig
.
36
.
NOTE-
Confirm
that
the
locking
tool
has
been
correctly
in-
stalled
by
trying
to
rotatethe
crankshaft
.
Page 112 of 759
117-
1
6
CAMSHAFT
TIMING
CHAIN
15
.
Remove
crankshaft
locking
tool
.
Remove
special
test
equipment
.
Insta¡¡
oil
supply
line
using
new
seals
and
reconnect
solenoid
connector
.
Remainder
of
installa-
tion
is
reverse
of
removal
.
Tightening
Torque
"
Cylinder
head
cover
to
cylinder
head
.
10
Nm
(89
in-lb)
"
VANOS
oil
supply
line
to
VANOS
control
unit
(banjo
bolt)
..
.........
32
Nm
(24
ft-Ib)
"
VANOS
solenoidlo
VANOS
control
unit
........
.
.
.
..
........
30
Nm
(22
ft-Ib)
VANOS
control
unit,
removing
Special
BMW
service
tools
are
required
lo
remove
and
in-
stall
the
VANOS
control
unit
.
Read
the
procedure
through
be-
forestarting
the
job
.
1
.
Remove
radiator
cooling
fan
shroud
and
cooling
fan
.
See
170
Radiator
and
Cooling
System
.
CAUTION-
Radiator
fan
has
left
hand
threads
.
2
.
Remove
top
plastic
engine
covers
.
Disconnect
ignition
coil
harness
connectors
from
coils
.
Remove
ignition
coils
.
Remove
cylinder
head
cover
.
Unclip
andremove
oil
baffle
cover
from
above
intake
camshaft
.See
113
Cylinder
Head
Removal
and
Installation
.
NOTE-
Make
note
of
the
mounting
bolt
insulator
arrangement
during
removal
of
the
cylinder
head
cover
.
3
.
Set
engine
lo
TDC
by
rotating
engine
in
normal
operat-
ing
direction
until
camshaft
lobes
at
cylinder
no
.
1
are
facing
each
other
and
"0/T"
mark
(0°TDC)
on
vibration
damper
lines
up
with
cast
boss
on
lower
timing
chain
cover
.
See
Fig
.
38
.
4
.
Lock
crankshaft
at
TDC
by
inserting
BMW
special
tool
no
.
11
2
300
through
transmission
bellhousing
and
finto
flywheel
or
drive
plate
.
Refer
to
Fig
.
36
given
earlier
.
NOTE-
Confirm
that
the
locking
tool
has
been
correctly
in-
stalled
by
trying
to
rotatethe
crankshaft
.
5
.
Remove
three
cylinder
head
cover
mounting
studs
from
rear
of
head
.
Lockcamshafts
at
TDC
bymounting
BMW
special
tool
no
.
11
3
240
at
ends
of
camshafts
.
Check
that
tool
is
squarely
seated
on
cylinder
head
gasket
surface
.
If
necessary,
rotate
camshafts
slightly
using
a24
mm
wrench
.
Refer
to
Fig
.
24
given
earlier
.
VANOS
(VARIABLE
VALVE
TIMING)
Fig
.
38
.
Camshafts
positioned
at
TDC-Cyl
.
No
.
1
cam
lobes
face
in
Note
0/T
mark
(0°TDC)
on
vibration
damper
alígned
with
boss
on
front
cover
.
CA
UTION-
Thecamshafts
mustbe
locked
in
the
TDC
position
using
the
specialservice
tool
or
an
equivalent
be-
fore
removing
the
timing
chain
.
Thearrows
on
the
sprockets
should
not
be
used
to
accurately
set
the
engine
to
TDC
The
special
tool
holds
the
cam-
shafts
parallel
to
each
other
and
perpendicular
to
the
valve
cover
gasket
surface
.
6
.
Disconnect
harness
connector
and
oil
line
fitting
from
bottom
of
VANOS
control
unit
.
NOTE-
Wrap
the
VANOS
oilfine
fitting
with
a
shop
rag
to
ab-
sorb
leaking
oil
.
7
.
Remove
two
access
plugs
from
VANOS
control
unit
in
frontof
exhaustcamshaft
sprocket
.
Loosen
4exhaustcamshaft
sprocket
mounting
bolts
but
do
not
remove
(Torx
El
0
socket)
.
NOTE-
Removal
of
the
access
plugs
allows
the
lower
exhaust
camshaft
sprocket
mounting
bolts
to
be
accessed
.
8
.
Depress
secondary
timing
chain
tensioner
and
lock
it
in
down
position
by
inserting
a
stiff
wire
into
rear
of
ten-
sioner
.
See
Fig
.
27
.
9
.
Remove
VANOS
control
unít
mounting
nuts
and
boltat
front
of
cylinder
head
.
Page 125 of 759
GENERAL
.
........
.
...........
.
.
.
.
.
.
.
120-1
Camshaft
Position
(CMP)
Sensor
....
.
.
.
...
120-6
Disabling
Ignition
System
.
.
.
.
.....
.
.
.
.
.
.
.
120-2
Camshaft
position
(CMP)
sensor,
replacing
Warnings
and
Cautions
.
.
.
.
.
.
.....
.
.
.
.
.
.
.
120-2
(4-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
120-6
Camshaft
position
(CMP)
sensor,
replacing
IGNITION
SYSTEM
DIAGNOSTICS
.
.
.
.
.
.
120-3
(6-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
120-7
Basic
Troubleshooting
Principles
...
.
.
.
.
.
.
.
120-3
Knock
sensors,
replacing
.
.
...
.
.
.
.
.
.
.
.
.
.
.
.
120-7
Ignition
Firing
Order
.....
.
...
.
.
.
.....
.
.
.
.120-7
IGNITION
SYSTEM
SERVICE
.
.........
.
120-3
Checking
for
Spark
..
.
.
.
.
.
.
.
.
.
.......
.
.
.
120-3
Ignition
coil,
testing
and
replacing
(4-cylinder
engine)
.
.
.
.
.
.
.
.
.
.
.........
.
120-3
Ignition
coil,
testing
and
replacing
(6-cylinder
engine)
.........
.
..........
120-4
Crankshaft
Positionlrpm
Sensor
.......
.
...
120-5
Crankshaft
position/rpm
sensor,
testing
and
replacing
(front
mounted)
.........
.
.
.
.
.
.
120-6
Crankshaft
position/rpm
sensor,replacing
(rear
mounted)
.....
.
.....
.
.....
.
.
.
.
.
.
120-6
GENERAL
Troubleshooting
and
testing
of
the
engine
management
system
should
be
carried
out
using
the
BMW
specialized
ser
This
repair
group
covers
repair
andcomponent
replace-
vice
tester
(scan
tool)
.
ment
information
for
the
ignition
system
.
All
engines
use
a
distributorless
ignition
system
with
indívid-
ual
ignitioncoils
for
each
cylinder
.
There
is
no
distributor
cap
NOTE-
or
ignition
rotor
.
Each
coil
can
be
selectively
controlled
by
the
"
Spark
plug
replacement
is
covered
in
020
Mainte-
engine
control
module
on
a
cylinder-by-cylinder
basis
.
On
later
nance
Program
.
systems,
knock
sensors
are
used
to
monitor
and
control
igni-
"
For
fuel
related
troubleshooting
and
testing,
see
130
tion
knock
(ping)
and
adjusttiming
accordingly
.
Fuel
lnjection
.
Ignition
timing
is
electronically
controlled
and
not
adjust-
All
engines
covered
by
this
manual
use
an
advanced
en-
able
.
The
engine
control
module
(ECM)
usesengine
load,
en-
gine
management
system
.
The
engine
management
system
gine
speed,
coolant
temperature,
and
intake
air
temperature
incorporates
on-board
diagnostics,
fuel
injection,
ignition
and
as
the
basic
inputs
for
timing
control
.
Knock
detection
is
also
other
advanced
engine
control
functions
.
an
input
to
the
control
module,
where
applicable
.
Table
a
.
Engine
Management
System
Variants
Engine
code
1
System
4-cylinder
M42
(1.8
I)
Bosch
DME
Ml
.7
M44
(1
.9
I)
Bosch
DME
M5
.2
(OBD
II)
6-cylinder
M50
1992
(2.5
I)
Bosch
DME
M8
.1
1993-1995
(2
.5
I)
Bosch
DME
M33
.1
M52
1996-1998
(2.8
I)
Siemens
MS
41
.1
(OBD
II)
1998
(2
.5
I)
Siemens
MS
41
.1
(013D
11)
S50US
(3.0
I)
Bosch
DME
M3
.3.1
S52US
(3.2
I)
Siemens
MS
41
.1
(OBD
II)
120
Ignition
System
IGNITION
SYSTEM
120-1
IGNITION
SYSTEM
SCHEMATICS
...
.
.
.
.120-7
TABLES
a
.
Engine
Management
System
Variants
......
120-1
b
.
Ignition
Coil
Resistance
(M42
engine)
......
120-4
c
.
Ignition
Coil
Resistance
(M44
engine)
......
120-4
d
.
Ignition
Coil
Resistance
(6-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.....
.
..
120-5
NOTE-
All
engines
coveredby
this
manual,
with
theexception
of
the
1992
M50,
incorporate
knocksensors
as
part
of
the
engine
management
system
.
The
initial
ignition
point
is
determined
by
the
crankshaft
po-
sition/rpm
sensor
during
cranking
.
Once
the
engine
is
run-
ning,
timing
is
continually
adjusted
based
on
operating
conditions
.
A
characteristic
ignition
map
is
shown
in
Fig
.
1
.
A
map
similar
to
the
one
shown
is
digitally
stored
in
the
engine
control
module
.
GENERAL
Page 127 of 759
IGNITION
SYSTEM
DIAGNOSTICS
IGNITION
SYSTEM
SERVICE
Poor
driveability
may
have
a
variety
of
causes
.
The
fault
On
4-cylinder
engines,
an
ignition
coil
pack
is
mounted
to
may
lie
with
the
ignition
system,
the
fuel
system,
parts
of
the
the
passenger
side
strut
tower
in
the
engine
compartment
.
emission
control
system,
or
a
combination
of
the
three
.
Be-
The
coil
pack
integrates
4
individual
coils
.
cause
of
these
interrelated
functions
and
their
effects
oneach
other,
it
is
often
difficult
to
know
where
to
begin
looking
for
On
6-cylinder
engines,
an
ignition
coil
is
located
directly
problems
.
above
each
spark
plug
.
For
this
reason,
effective
troubleshooting
should
alwaysbe-
gin
with
an
interrogation
of
the
On-Board
Diagnostic
(OBD)
system
.
The
OBD
system
detects
certain
emissions-related
engine
management
malfunctions
.
When
faults
are
detected,
the
OBD
system
stores
a
Diagnostic
Trouble
Code
(DTC)
in
the
system
ECM
.
In
addition,
the
Check
Enginewarning
light
will
come
on
if
an
emissions-related
fault
is
detected
.
Two
generations
of
OBD
areusedon
the
cars
coveredby
this
manual
.
See
100
Engine-General
for
OBD
information
.
On-Board
Diagnostics
"
1992-1995
models
............
...
.
..
...
OBD
I
"
1996
and
later
models
.........
.......
..
OBD
II
NOTE-
"
On
carswith
OBD
ti,
specialized
OBD
11
scan
tool
equipment
mustbeused
to
access
DTCs,
either
using
the
BMW
special
tool
or
a
`generic"
OBD
11
scan
tool
.
"
The
OBD
11
fault
memory
(including
an
illuminated
Check
Engine
light)
can
only
be
reset
using
the
spe-
cial
scan
tool
.
Removing
the
connector
from
the
ECM
or
dísconnecting
the
battery
will
not
erase
the
fault
memory
.
Basic
Troubleshooting
Principies
An
engine
that
starts
and
runs
indicates
the
ignition
system
is
fundamentally
working-delivering
voltage
toat
least
some
of
the
sparkplugs
.
A
hard-starting
or
poor-running
engine,
however,
may
indicate
ignition
coil
problems,
cracked
or
dete-
riorated
spark
plug
wires
(4-cylinder
engines
only),
and
worn
or
fouled
spark
plugs
.
WARNING
-
Inefficient
combustion
(richair/fuel
mixture)
can
cause
the
catalytic
converter
to
overheat
and
plug
.
An
overheated
catalytic
converter
can
also
bea
tire
hazard
.
Checking
for
Spark
IGNITION
SYSTEM
120-
3
WARNING
-
If
a
spark
test
is
done
incorrectly,
damage
to
theen-
gine
control
module
(ECM)
or
the
ignitioncoil(s)
may
result
.
Checking
for
spark
is
difficult
onengines
with
distributorless
ignition
systems
.
Try
Rmovng
the
plugs
and
inspecting
for
differences
be-
tween
them
.
A
poor-firing
plug
may
be
wet
with
fuel
and/or
black
and
sooty,
butnot
always
.
If
a
coil
is
not
operating,
the
engine
management
system
will
electrically
disable
the
fuel
injectorto
that
cylinder
.
The
key
is
to
look
for
differences
be-
tween
cylinders
.
Ignition
coil,
testing
and
replacing
(4-cylinder
engine)
1.
Disconnect
mainharness
connector
from
coils
:
"
On
M42
engine,
remove
plastic
covering
from
coils
and
disconnect
individual
harness
connectors
.
"
On
M44
engine,
disconnect
main
harness
connectorat
end
of
coil
pack
.
See
Fig
.
3
.
Fig
.
3
.
Ignition
coil
pack
for
M44
engine
(arrow)
.
Coil
harness
con-
nector
shown
at1
.
IGNITION
SYSTEM
SERVICE
Page 128 of 759
120-
4
IGNITION
SYSTEM
2
.
Check
for
battery
voltage
o
cofs
.
If
voltage
is
not
Table
b
.
Ignition
Coil
Resistance
present,
check
wire
between
terminal
15
and
ignition
(M42
Engine)
switch
.
See
Electrical
Wiring
Diagrams
.
"
On
M42
engine,
connect
digital
multimeter
between
ter-
minal
15(+)
in
each
harness
connector
and
ground
.
See
Fig
.
4
.
"
On
M44
engine,
connect
voltmeter
between
terminal
2
(15+)
in
connector
and
ground
.
Turn
ignition
on
and
check
for
voltage
.
See
Fig
.
5
.
3
.
Turn
ignition
off
.
0
4a15
Fig
.
4
.
Ignition
coil
harness
connector
terminal
identification
for
M42
engine
.
Fig
.
5
.
Ignition
coil
harness
connector
terminal
identification
for
M44
engine
.
CAUTION-
The
wiring
to
the
coil(via
the
ignition
switch
15+)
is
not
fuse
protected
.
Use
care
when
testing
thiscircuit
.
4
.
Use
a
digital
multimeter
totest
coil
primary
resistance
.
"
On
M42
engine,
use
Table
b
asa
guide
to
check
coil
resistance
.
Make
checks
at
each
harness
connector
.
"
On
M44
engine,
use
Table,c
as
a
guide
to
check
coil
primary
resistance
.
5
.
Inspect
coil
housing
for
hairline
cracks
or
leaking
cast-
ing
material
.
See
Fig
.
7
.
A
leaky
ignition
coil
may
indi-
11502
cate
a
faulty
ECM
(engine
control
module)
.
Check
the
ECM
before
installing
a
new
coil
.
Fig
.
6
.
Ignition
coil
harnessconnector
terminal
identification
for
6-
cylinder
engine
.
IGNITION
SYSTEM
SERVICE
11502
Terminals
Resistance
(refer
to
Fig
.
4
.)
Coil
primary
1
(-)
and
15
(+)
10
.4-0
.8
ohms
Coil
secondary
N
.A
.
N
.A
.
Table
c
.
Ignition
Coil
Resistance
(M44
Engine)
Terminais
Resistance
(referto
Fig
.
5
.)
Coil
#1
primary
1
(-)
and
2
(+)
0
.4-0
.8
ohms
Coil
#2
primary
6
(-)
and2
(+)
0
.4-0
.8
ohms
Coil
#3
primary
7
(-)
and
2
(+)
0
.4-0
.8
ohms
Coil
#4
primary
5
(-)
and2
(+)
0
.4-0
.8
ohms
Coil
secondary
N
.A
.
N
.A
.
NOTE-
If
a
single
coilís
faulty
on
M44
engines,
the
complete
coil
pack
will
have
to
be
replaced
.
Ignition
coil,
testing
and
replacing
(6-cylinder
engine)
CAUTION-
Use
a
digital
multimeter
for
the
following
tests
.
1.
Remove
plastic
enginecovers
from
top
of
engine
by
prying
off
nut
covers
and
removingcover
mounting
nuts
.
See
113
Cylinder
HeadRemoval
and
Installa-
tion
.
2
.
Disconnect
harnessconnectorfromcof
.
Connect
mul-
timeter
between
terminal
15
(+)
in
connector
and
ground
.
See
Fig
.
6
.
3
.
Turn
ignition
on
and
check
for
batteryvoltage
.
"
If
batteryvoltage
is
not
present,
check
wire
between
terminal
15
and
ignition
switch
.
See
Electrical
Wiring
Diagrams
.
"mozo
Page 129 of 759
CAUTION
-
The
wiring
to
termina¡
15
(+)
of
the
coil(vía
the
ig-
nition
switch)
is
not
fuse
protected
.
Use
care
when
testíng
thiscircuit
.
4
.
Turn
ignition
off
.
5
.
Use
a
multimeter
to
test
coil
primary
resistanceat
coil
terminals
.
See
Table
d
.
Table
d
.
Ignition
Coil
Resistance
(6-cylinder
Engine)
Terminals
Resistance
(referto
Fig
.
4
.)
Coil
primary
1
1
(-)
and
15
(+)
X
0
.4-0
.8
ohms
Coil
secondary
l
N
.A
.
N
.A
.
6
.
Remove
coil
and
inspect
coil
housing
for
hairline
cracks
or
leaking
casting
material
.
See
Fig
.
7
.
A
leaky
ignition
coil
may
indícate
a
faulty
engine
control
module
(ECM)
.
Check
ECM
before
installing
a
new
coil
.
811004
Fig
.
7
.
Ignition
coil
being
removed
on
6-cylinder
engine
(M52
engine
shown)
.
CA
UTION-
"
Note
location
of
coil
ground
straps
before
coilre-
moval
;
reinstallin
the
same
location
.
"
When
replacing
ignition
coils,
ensure
that
the
re-
placement
coil(s)
are
from
the
same
manufactur-
er
containing
the
same
partlcode
numbers
.
If
individual
coils
with
the
correct
specifications
are
not
available,
all
coils
should
be
replaced
.
IGNITION
SYSTEM
120-
5
Crankshaft
Position/rpm
Sensor
If
the
engine
control
module
(ECM)
does
not
receive
a
crankshaft
position
signal
during
cranking,
the
engine
will
not
start
.
On
1992-1995(pre-OBD
II)
cars,
the
crankshaft
posi-
tion/rpm
sensor
is
mounted
on
the
front
engine
cover
and
reads
the
toothed
vibration
dampener
wheel
.
See
Fig
.
8
.
Fig
.
8
.
Crankshaft
position/rpm
sensor
mounted
at
front
of
engine
on
1992-1995
cars
.
(arrow)
.
On
1996
and
latee
cars
(OBD
II
compliant),
the
crankshaft
position/rpm
sensor
is
mounted
in
the
left
rear
side
of
the
cyl-
inderblock
.
The
sensor
reads
a
toothed
wheel
mounted
to
the
end
of
the
crankshaft
.
See
Fig
.
9
.
Fig
.
9
.
Crankshaft
position/rpm
sensor
toothed
wheel
mounted
to
rear
of
crankshaft
OBD
II
compliant
cars
.
The
sensor
is
mounted
in
the
left
rear
side
of
the
cylinder
block
.
IGNITION
SYSTEM
SERVICE