1994 BMW 325i intake

Fig
.
36
.
BMW
special
tool
no
.
11
2
300
installed
through
bellhousing
and
finto
flywheel
.

8
.
Remove
oil
line
fitting
from
VANOS
control
unit
.

NOTE-

Wrap
the
VANOS
oil
line
fitting
with
a
shop
to
absorb
leaking
oil
.

9
.
Using
hollow
bolt
and
seals
from
oil
supply
line,
instan

BMW
special
tool
no
.
11
3
450
(air
line
fitting)
and
con-
nect
a
supply
of
compressed
air
(30-115
psi)
to
VANOS

oil
fitting
.

10
.
Measure
and
record
distance
between
trigger
plate

edge
and
side
of
secondary
timing
chain
tensioner
.

See
Fig
.
37
.

Fig
.
37
.
VANOS
reference
measurement
(dimension
A)
between
trig-
ger
píate
(sender
gear)
and
side
of
secondary
chain
tensioner
.

CAMSHAFT
TIMING
CHAIN



117-
1
5

11
.
Disconnectharness
connector
from
VANOS
solenoid
.
Connect
BMW
special
tool
no
.
12
6
410
(electrical
test
lead)
to
VANOS
solenoid
connector
.

"
Connect
positive
(+)
test
lead
to
positive
(+)
terminal
ofbattery
Connect
negative
(-)
test
leadto
chassis
ground
.
solenoid
should
audibly
click
and
intake
cam-
shaft
should
advance
.

CA
UTION-

"
Be
sure
to
connect
the
test
hamess
polaritycor-
rectly
.
lf
the
polarity
is
reversed,
the
intemal
diode
in
the
VANOS
solenoid
will
be
destroyed
.
Although
the
solenoid
will
still
functionwith
a
faultydiode,
a
fault
code
may
be
set
in
the
ECM
memory
.

"
To
confirm
voltage
polarity,
turn
the
ignition
on
and
check
for
positive
(+)
batteryvoltage
at
the
terminal
corresponding
to
the
redlwhite
wire
in
the
main
harness
connector
.
Check
that
the
pos-
itive
terminal
(+)
in
the
main
connector
corre-
sponds
to
the
same
terminal
in
the
solenoid
connector
that
is
being
connected
to
the
battery
.

12
.
With
solenoid
actuated,
measure
and
record
new
dis-

tance
between
trigger
plate
edge
and
side'of
second-
ary
timing
chain
tensioner,
as
shown
in
Fig
.
37
.

13
.
Difference
between
first
measurement
(step
10)
andsecond
measurement
(step12)
should
be
at
least
8
.5
mm
(0
.3346
in
.)
.
lf
any
faults
arefound,
solenoid
may

be
faulty,
or
hydraulic
control
unit
may
be
faulty
or
incor-
rectly
installed
.

14
.
Check
VANOS
solenoid
byremoving
it
from
control
unit
.
Check
that
solenoid
plunger
and
control
unit

plunger
move
freely
.
Install
solenoid
using
tighteníng

torque
given
below
.

NOTE-

"
The
solenoid
is
available
asareplacement
part
.
lf
the
control
unit
plunger
is
sticking,
the
complete
control
unit
will
have
to
be
replaced
.

"lf
the
VANOS
system
does
not
advance
correctly
and
no
other
faults
can
be
found,
itis
possible
that
the
VANOS
control
unit
may
Nave
been
fnstalled
incor-
rectly-especially
if
the
camshaft
sprockets
have
pre-
víously
been
removed
for
other
repairs
.
Check
the
installation
by
removing
and
reinstalling
the
control
unit
as
described
later
.

VANOS
(VARIABLE
VALVE
TIMING)

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
.

10
.
On
cars
built
up
to
3/95
:
Slide
control
unit
off
front
of
cylinder
head,
hand
turning
the
exhaust
sprocket
clock-
wise
(as
viewedfrom
front)
as
the
unit
is
removed
.

11
.
On
cars
built
3/95
and
latee
:
Use
a
spanner
toolto
ro-
tate
exhaust
sprocket
until
stop
on'
intake
sprocket
is
contacted
.
See
Fig
.
39
.
Then
slide
control
unit
off
front
of
cylinder
head
.

EMAÑ

0012514

Fig
.
39
.
On
VANOS
control
unit
withspringplate
(cars
built
3/95
and
later),
rotate
exhaust
camshaft
sprocket
clockwise
until
intake



NOTE-
camshaft
contacts
stop
.
BMW
special
tool11
5490shown
.



BMW
special
tool
no
.
113
'390
is
a
dummy
chain
ten-
sioner
and
simulates
the
function
of
thetensioner
.

VANOS
control
unit,
installing

CAUTION
-

Incorrect
installation
of
the
VANOS
control
may
result
in
damage
to
the
engine
valvetráin
.

1
.
Lock
camshafts
and
crankshaft
in
TDC
positionwith
BMW
special
tools
as
described
above
in
removal
pro-

cedure
.

CA
UTION-

The
camshafts
and
crankshaft
mustbe
locked
in
the
TDC
position
using
BMW
special
tools
no
.
11
2
300and
113
240
.
If
the
camshafts
and
crank-
shaft
are
not
at
TDC,
the
valves
can
contact
the
pistons
when
the
engine
is
turned
over
.

NOTE-

Be
sure
the
secondary
timing
chain
tensioner
is
locked
down
and
the
exhaustcamshaft
mounting
bolts
are
loosebefore
proceeding
.

2
.
Remove
primary
timing
chain
tensioner
from
side
of

cylinder
head
.
See
Fig
.
40
.

CAMSHAFT
TIMING
CHAIN



117-
1
7

Fig
.
40
.
Primary
timing
chain
tensioner
(arrow)
.
Remove
tensioner
slowlyto
relieve
spring
tension
beneath
end
plug
.

3
.
Install
BMW
special
tool
no
.
11
3
390
into
primary
tim-
ing
chain
tensionersleeve
.
Thread
tool
in
finger
tight
to
remove
chain
slack
.

4
.
Hand
turn
secondary
sprocketsclockwise
(as
viewed
from
front
of
engine)
until
sprockets
contact
stops
.

5
.
Apply
a
small
amount
of
¡¡quid
gasketsealer
(3-Bond

1209
®
or
equivalent)
to
VANOS
housing
alignment

doweis
on
front
of
cylinder
head
.
lnstall
a
new
gasket
.

6
.
Push
VANOS
piston
gear
cup
finto
VANOS
housing
until

it
bottoms
out
in
housing
.
Position
VANOS
control
unitinto
place,
but
do
not
engage
splines
on
gear
cup
.

7
.
On
cars
built
up
to
3/95
:

"
Hand
turn
exhaust
sprocketcounterclockwise
(as

viewedfrom
front
of
engine)
only
enough
to
mesh
gear
cup
splines
with
camshaft
gear
:
"
Slowly
push
VANOS
control
unit
in
untilfully
seated,
guiding
chains
in
counterclockwise
direction
.

VANOS
(VARIABLE
VALVE
TIMING)

117-
1
8



CAMSHAFT
TIMING
CHAIN

CAUTION-

It
is
crítical
that
the
exhaustcamshaft
sprocket
be

turned
only
the
mínimum
amount
necessary
to

engage
the
gear
cup
.
If
this
procedure
is
done
ín-
correctly,
the
VANOS
system
may
not
function

throughout
íts
full
range
.

NOTE-

As
the
control
unit
isinstalled,
the
secondary
sprockets
will
rotate
in
the
counterclockwise
direction
.
It
may
be

necessary
to
guide
sprockets
counterclockwise
as
the

control
unit
is
installed
.

8
.
On
cars
built
from3/95
:
Use
a
spanner
tool
(See
Fig
.

39
.),
turn
exhaust
sprocket
counterclockwise
(as

víewed
from
front
of
engine)
only
enough
to
mesh

gear
cup
splines
with
camshaftgear
.
Slowly
push

VANOS
control
unit
towards
camshaft
until
it
is
fully

seated,guiding
chains
in
counterclockwise
direction
.

CA
UTION-

Ensure
that
the
first
available
tooth
engages
.

9
.
Install
and
tightencontrol
unit
nuts
and
bolt
.

10
.
Connect
harness
connector
to
VANOS
solenoid
.
Using

new
seals,
insta¡¡
oil
line
fitting
.

Tightening
Torques

"
VANOS
control
unitto
cylinder
head

M6
nut
.....
..
..
.
.
.............
10
Nm
(89
in-lb)

M8
bolt
.....
.
.
.
.
..
.............
22
Nm
(17
ft-Ib)

"
VANOS
oil
supply
line
to
control
unit
.
32
Nm
(24
ft-Ib)

11
.
Slowlyunlock
and
release
secondary
chain
tensioner
.

12
.
Preloadprimary
chain
by
tightening
BMW
special
tool

no
.
112
240
(dummy
chain
tensioner)
to
1
.3
Nm
(11
in-
lb)
.
Then
tighten
exhaust
camshaft
sprocket
mounting

bolts
alternately
in
two
stages
.

Tightening
Torque

"
Secondarytiming
chain
sprockets
to
camshafts

(Tora
boits)

Stage
1
..
...............
...
.
.
...
5
Nm
(44
in-lb)

Stage
2
..
...............
...
.
.
..
22
Nm
(17
ft-Ib)

VANOS
(VARIABLE
VALVE
TIMING)

13
.
Remove
flywheel
locking
tool
from
transmission
bell-

housing
.
Remove
camshaft
locking
tool
from
rear
of

cylinder
head
.

14
.
Turn
engine
over
by
hand
at
least
two
fui¡
crankshaft
ro-

tations
.
Reinstall
camshaft
locking
tool
and
flywheel

locking
toolto
make
sure
all
adjustments
are
correct
.
If

settings
are
correct,
remove
locking
tools
.

15
.
Remove
BMW
special
tool
112
420
(dummy
chain
ten-
sioner)
from
side
of
cylinder
head
.
Install
primary
chain

tensioner
so
that
cutout
in
tensioner
piston
engages

chain
rail
.
See
Fig
.
34
.
Using
new
seals,
install
and

tighten
access
plugs
in
VANOS
control
unit
.

Tightening
Torque

"
Access
plugs
to

VANOS
control
unit
.
..
.
.....
.
..
...
50
Nm
(37
ft-lb)

"
Primary
timing
chain
tensioner
plug
to
tensioner
sleeve

M50/S50USengine
.
.
..
.
.
...
.
...
..
50
Nm
(37
ft-Ib)

M52/S52US
engine
...
..
...
...
...
40
Nm
(30
ft-Ib)

16
.
Install
oil
baffle
cover
above
intake
camshaft
.
Install

three
cylinder
head
covermounting
studs
to
rear
of

head
.
Instali
cylinder
head
cover
.

Tightening
Torque

"
Cylinder
head
cover

to
cylinder
head
(M6
screws)
......



10
Nm
(89
in-Ib)

17
.
Installationof
remaining
parts
is
reverse
of
removal
.

NOTE-

Be
sure
to
install
the
ground
wíres
at
the
cylinder
head
cover
mounting
studs
and
at
the
front
of
the
cylinder
head,
if
applicable
.

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
.

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

120-
6



IGNITION
SYSTEM

Crankshaft
position/rpm
sensor,

testing
and
replacing
(front
mounted)

1
.
Disconnect
sensor
harness
connector
.

2
.
Using
a
digital
multimeter,
check
resistance
between
terminals
1
and
2
in
connector
.
See
Fig
.
10
.

n1
n2n3

Fig
.
10
.
Crankshaft
position/rpm
sensorconnector
.

Crankshaft
positionlrpm
sensor
specifications

"
Coil
resistance
(approx
.)
terminais
1
and
2
....
.
..
...
....
1280
±
10%
ohms

"
Air
gap
(sensor
distance
from
toothed
wheel)
..
.
.
........
.1
.0
±
0
.3
mm
(0
.04
±
0
.01
in
.)

3
.
If
the
resistance
is
not
correct,
the
sensor
is
faulty
and
should
be
replaced
.

NOTE
-

When
installing
the
new
sensor,
be
sure
thewiring
Is
rerouted
in
the
same
orientation
.
Secure
the
sensor
us-
ing
new
wire
ties
.

Tightening
Torque

"
Crankshaft
position/rpm
sensor
to
mounting
bracket
.........
.
.
5
t
1
Nm
(62
t
9
in-lb)

Crankshaft
position/rpm
sensor,



4
.
Installation
is
reverse
of
removal
.
Use
a
new
O-ring
replacing
(rear
mounted)



when
installing
sensor
.
Be
sure
wiring
is
rerouted
in
same
orientation
.
1
.
Disconnect
sensor
harness
connector
.

6502AGN56

2
.
Locatesensor
on
rear
left
sideof
cylinder
block
.
Re-
move
sensormounting
bolt
and
remove
sensorfrom
cylinder
block
.

IGNITION
SYSTEM
SERVICE

3
.
Installation
is
reverse
of
removal
.
Use
a
new
O-ring

when
installing
sensor
.
Be
sure
wiring
is
rerouted
in
same
orientation
.
Secure
sensor
using
new
wire
ties
.

NOTE-

It
may
be
easier
to
remove
the
sensor
working
from
the
underside
of
the
vehicle
.

Camshaft
Position
(CMP)
Sensor

The
camshaft
position
(CMP)
sensor
is
usedby
the
engine
management
system
for
sequential
fuel
injection
and
knock
control
.

Camshaft
position
(CMP)
sensor,

replacing
(4-cylinder
engine)

1
.
Remove
CMP
sensorfromtop
timing
cover,
just
above
coolantthermostat
housing
.
See
Fig
.
11
.

Fig
.
11
.
Camshaft
position
sensor
mounting
bolt
(arrow)
.
M42
engine
shown
.

2
.
On
M42
engines
to
9/93
:
Disconnect
CMP
harness
plug
just
above
oil
filter
housing
.

3
.
On
M42
from9/93
and
all
M44
engines
:
Remove
upper
intake
manifold
as
described
in
113
Cylinder
Head
Re-
moval
and
Installation
.
Then
unplug
CMP
sensor
har-
ness
connector
below
manifold
.

Camshaft
position
(CMP)
sensor,

replacing
(6-cylinder
engine)

1
.
Remove
plastic
cover
from
above
fuel
injectors
.

2
.
Disconnect
harness
connector
from
VANOS
solenoid

and
unscrew
solenoid
from
VANOS
control
unit
.
Re-



"
Clean
contactsurface
on
engine
block
before
fnstall

move
oil
supply
line
from
VANOS
control
unit
.
See
117



ing
knock
sensors
.

Camshaft
Timing
Chain
.

3
.
Remove
camshaft
position
(CMP)
sensor
from
left
frontof

cylinder
head,
next
to
top
of
oil
filter
housing
.



"
Knock
sensor
to
cylinder
block
....
20
Nm
(15
ft
.
lbs
.)

4
.
Disconnect
CMP
sensor
harnessfrom
under
intake

manifold
.

5
.
Installation
is
reverse
of
removal
.
Use
a
new
O-ring

when
installing
sensor
.
Be
sure
wiring
is
rerouted
in

same
orientation
.

Tightening
Torques

"
CMP
sensor
to
cylinder
head
....
.
.
..
5
Nm
(3
.5
ft-Ib)

"
VANOS
oil
supply
pipe
to

VANOS
control
unit
...........
.
..
32
Nm
(24
ft-Ib)

"
VANOS
solenoid
to
VANOS

control
unit
...
.
.................
30
Nm
(22
ft-Ib)

Knock
sensors,
replacing

Knock
sensors
are
usedon
engines
with
Bosch
DME
M1
.7,

Bosch
DME
M3
.3
.1,
Bosch
DME
M5
.2,
and
Siemens
MS
41
.1

engine
management
systems
.
The
knocksensors
are
bolted
to
the
left
sideof
the
cylinder
block
and
monitor
the
combus-

tion
chamber
for
engine-damaging
knock
.
If
engine
knock
is

detected,
the
ignition
point
is
retarded
accordingly
via
the
en-

gine
control
module
.

CA
UTION-

"
Label
knock
sensorharness
connectors
before

disconnecting
them
.
The
connectors
must
not
be

interchanged
.
Engine
damage
may
result
if
the
sensors
are
monitoring
the
wrong
cytinders
.

"
Note
the
installed
angle
of
the
knock
sensoron
the

block
before
removing
it
.
Reinstall
the
sensor
in

the
same
position
.
Be
sure
to
usea
torque
wrench

when
tightening
the
sensormounting
bola

NOTE
-

"
On
M52
engines,
a
single
harness
connects
the
twosensors
to
the
main
harness
connector
.
The
shorter
cable
lead
fs
for
the
knock
sensor
for
cytinders
4,
5,
and
6
.

Tightening
Torque

IGNITION
SYSTEM



120-
7

0012730

Fig
.
12
.
Knock
sensor
mounting
bolt
on
front
left
side
of
cylinder

block
.

NOTE-

Knock
sensor
function
Is
monitoredby
the
On-Board
Diagnostic
system
.
If
a
knock
sensor
is
detected
to
be
faulty,
an
appropriatediagnostic
trouble
code
(DTC)
may
be
stored
in
memory
.
See
100
Engine-General
for
information
on
retrieving
DTCs
.

On
6-cylinder
engines,
the
knock
sensors
are
accessible
af-
ter
removing
the
intake
manifold
.
On
4-cylinder
engines,
the

upper
section
of
the
intake
manifold
should
be
removed
to
ac-

cess
the
sensors
.
See
Fig
.
12
.
NOTE-

Intakemanifold
removal
and
installation
procedures
are



"
Cylinder
no
.
1is
at
the
front
of
the
engine
.

covered
in
113
Cylinder
HeadRemoval
and
Installation
.

Ignition
Firing
Order

Ignition
Firing
Order

"
4-cylinder
engines
.....
..
...
.
..........
.1-3-4-2

"
6-cylinder
engines
...........
..
.
.
..
..
1-5-3-6-2-4

IGNITION
SYSTEM
SCHEMATICS

Fig
.
13
through
Fig
.
17
show
ignition
system
schematics

usedon
the
enginescoveredby
this
manual
.

IGNITION
SYSTEM
SCHEMATICS