1992 BMW 325i 1992
[x] Cancel search: 1992Page 106 of 759
117-
1
0
CAMSHAFT
TIMING
CHAIN
21
.
On
1993
and
lates
engines
:
Remove
access
plugs
from
24
.
On
1993
and
later
engines
:
VANOS
control
unit
in
front
of
exhaust
camshaft
"
Remove
VANOS
control
unit
as
described
laterinthis
sprocket
.
Remove
4
bolts
from
exhaust
camshaft
repair
group
.
sprocket
(useTono
El0
socket)
.
See
Fig
.
26
.
"
Remove
intake
camshaft
sprocket
mounting
nuts
.
"
Remove
intake
and
exhaust
sprockets
together
with
secondary
chain
.
Note
location
of
thrust
washers
and
spring
plate
(where
applicable)
on
intake
sprocket
.
Fig
.
26
.
Exhaust
camshaftmounting
bolts
(arrows)
.
CAMSHAFT
TIMING
CHAINS,
6-CYLINDER
0013056
22
.
Depress
secondary
timing
chain
tensiones
and
lock
down
by
inserting
stiff
wire
into
the
openings
in
rear
of
tensioner
.
See
Fig
.
27
.
Fig
.
27
.
Secondary
timing
chaintensioner
being
locked
down
on
M50
engine
.
Press
tensioner
downand
insert
locking
wire
through
holes(arrows)
.
Tensioner
on
M52/S52
US
engines
vary
slight-
23
.
Remove
secondary
chain
tensioner
and
lift
out
primary
chain
guide
.
NOTE-
Hold
the
camshaft
stationary
(at
hex
on
camshaft)
when
loosening
ortightening
sprocket
mounting
boits
.
CAUTION-
The
crankshaft
must
not
be
allowed
to
rotate
once
the
timing
chain
is
removed
.
The
pistons
can
con-
tact
the
valves
.
25
.
On
1992
engines
:
"
Remove
from
intake
and
exhaust
sprocket
mounting
bolts
.
"
Remove
sprockets
together
with
secondary
chain
.
26
.
Remove
bolts
holding
lower
timing
chain
cover
to
cylin-
der
head
(use
Torx
E8
socket)
.
See
Fig
.
28
.
MR111:
R
Fig
.
28
.
Cylinderhead-to-timingchain
covermounting
bolts
(arrows)
.
27
.
Using
a
drift,
drive
two
locatiog
dowels
in
left
and
right
sides
of
lower
timing
chaincover
toward
rear
of
car
.
Re-
move
covermounting
boits
and
carefully
lift
cover
off
.
See
Fig
.
29
.
CA
UTION-
Use
care
when
removing
the
cover
from
the
cylin-
der
head
gasket
.
If
the
cover
is
stuck,
useasharp
knife
to
separate
it
from
the
head
gasket
.
Page 108 of 759
117-
1
2
CAMSHAFT
TIMING
CHAIN
4
.
Mount
primary
timing
chain
sprocket
to
primary
chain
so
that
arrowon
sprocket
faces
up
.
Mount
sprocket
to
camshaftso
that
tapped
holes
in
camshaftare
on
left
side
of
elongated
holes
in
sprocket
.
See
Fig
.
31
.
NOTE-
On
engines
built
beginning
from
March
1995,
the
VANOS
intake
cam
sprocket
assembly
was
updated
to
ínclude
a
spring
plate
and
two
thrust
washers
.
See
Fig
.
Fig
.
31
.
Primary
timing
chain
sprocket
correctly
alignedto
exhaust
33
.
camshaft
.
Elongated
sprocket
holes
should
be
aligned
to
left
side
of
threaded
camshaft
holes
.
5
.
On
1993
and
later
engines
:Install
BMW
special
tool
no
.
11-3
390
into
primary
timíng
chain
tensionersleeve
.
Thread
toolin
finger
tight
until
slack
is
removed
from
chain
.
"
Check
that
elongatedholes
in
primary
sprocket
are
centered
to
bolt
holes
in
camshaft
and
chain
is
free
of
slack
.
NOTE-
BMW
special
tool
no
.
11
3
390
ís
a
dummy
primary
chaín
tensioner
and
simulatesthe
function
of
the
hy-
draulic
tensíoner
.
7
.
Install
cylinder
identification
trigger
píate
to
front
of
in-
take
camshaft
.
On
1993
and
later
engines,
instanthrust
washer
tofrontof
intake
camshaft
.
CAMSHAFT
TIMING
CHAINS,
6-CYLINDER
B11136
Fig
.
32
.
Secondary
chain
sprockets
being
installed
.
Attach
sprockets
with
arrows
pointing
up
and
elongated
holes
centered
to
threaded
holes
in
shaft
flange
.
6
.
Install
primary
timing
chainguide
and
secondary
chain
tensioner
.
Tighten
mounting
bolts
.
(Tensioner
remains
Fig
.
33
.
VANOS
spring
plate
and
thrust
washers
on
engines
built
3/95locked
down
for
now
.)
and
later
.
10
.
On
1993
and
later
cars,
tighten
nuts
at
intake
camshaft
sprocket
.
8
.
Insta¡¡
secondary
chainsprockets
and
chain
asan
as-
sembly
so
that
arrows
on
sprockets
are
pointing
up
.
Tightening
Torque
(1996
and
later)
Centermounting
holes
in
sprockets
tobolt
holes
in
"
Intake
camshaft
sprocket
nut
camshafts
.
See
Fig
.
32
.
to
stud
(M6)
.............
.10t
1
Nm
(89
±9
in-lb)
9
.
On
1993
and
later
engines
:
Insta¡¡
thrust
washers
and
spring
plate
(where
applicable)
to
intake
cam
sprocket
.
11
.
On
1992
engines
:
Insta¡¡
primary
chain
tensioner
so
that
cutout
in
tensioner
piston
engages
chain
rail
.
See
Fig
.
34
.
Check
that
chain
is
free
of
slack
.
Page 109 of 759
Fig
.
34
.
Primary
timíng
chain
tensioner
being
instafed
.
Pistoncutout
mustbe
in
position
shown
to
engage
chain
rail
.
12
.
On
1993
and
later
engines
:
Install
VANOS
control
unit
as
described
later
in
this
repair
group
.
13
.
Unlock
and
release
secondary
chaintensioner
.
NOTE-
On
pre-VANOS
engines,
be
sure
toinstall
the
3mm
drill
bits
on
left
and
right
sides
of
tool
.
14
.
On
1992
engines
:
Tighten
intake
and
exhaust
timing
chain
sprocket
bolts
alternately
in
two
stages,
working
at
intake
side
first
.
Tightening
Torques
"
Secondary
timing
chaira
sprockets
to
camshafts
(M7
Torx
bolts)
Stage
1
....
.
.
.
...
...............
5
Nm
(44
in-lb)
Stage
2
..
.
.
.
.
.
.
................
22
Nm
(17
ft-Ib)
15
.
On
1992
engines
:
Install
upper
timing
chaincover
to
cylinder
head
using
a
new
gasket
.
Apply
a
small
amount
ofliquid
gasket
sealer
(3-Bond
1209
®
orequiv-
alent)
around
coveralignment
dowels
.
16
.
On
1993
and
later
engines
:
Preloadprimary
chain
by
tightening
BMW
special
tool
no
.
11
3
390
(dummy
21
.
Install
cylinder
head
cover
mounting
studs
.
Insta¡¡
oil
chain
tensioner)
to
1
.3
Nm
(11
in-lb)
.
Then
tighten
ex-
baffle
cover
.
Install
cylinder
head
cover
.
haust
camshaft
sprocket
bolts
alternately
in
twostages
.
Tightening
Torques
(1993
and
later
engines)
"
Exhaust
camshaft
sprockets
to
camshafts
(M7
Torx
bolts)
Stage
1
..
...
..
..
................
5
Nm
(44
in-lb)
Stage
2
.....
.
.
...
..............
22
Nm
(17
ft-Ib)
17
.
Remove
flywheel
locking
tool
from
transmission
bell-
housing
.
Remove
camshaft
locking
tool
from
rear
of
cylinder
head
.
CAMSHAFT'TIMING
CHAIN
117-
1
3
18
.
Insta¡¡
crankshaft
hubandwasher
while
aligning
woo-
druff
key
.
Hold
hub
stationary
and
tighten
mounting
bolt
.
Install
vibration
damper
and
pulley,
making
sure
that
lo-
cating
pin
in
hub
engages
hole
in
vibration
damper
.
NOTE-
When
installing
crankshaft
hub
mounting
bolt,
the
stepped
(shouldered)
sideof
the
washer
should
fase
the
hub
.
Tightening
Torques
Crankshaft
hub
to
crankshaft
(stretch
bolt-
always
replace)
........
410
±
20
Nm
(300
±
15
ft-1b)
"
Vibration
damper
and
pulley
to
crankshaft
hub
(M8)
...
..
.
..
....
22
Nm
(17
ft-Ib)
19
.
Turn
engine
over
by
hand
in
direction
of
rotation
atleast
two
full
rotations
.
Reinstall
camshaft
and
crankshaft
locking
tools
to
check
engine
timing
.
Remove
locking
tools
if
no
faults
are
found
.
20
.
On
1993
and
later
engines
:
Remove
BMW
special
tool11
3
390
(dummy
tensioner)
.
Install
primary
chain
ten-sioner
so
that
cutout
in
tensioner
piston
engages
the
chain
rail
.
See
Fig
.
34
.
Install
and
tighten
access
plugs
in
VANOS
control
unit
.
Tightening
Torques
"
Access
plugs
to
VANOS
control
unit
..........
.
..
50
Nm
(37
ft-Ib)
"
Primary
timing
chain
tensioner
to
tensioner
sleeve
M50/S50US
engine
.......
.
..
..
.
.
50
Nm
(37
ft-Ib)
M52/S52US
engine
..........
..
.
.
40
Nm
(30
ft-Ib)
Tightening
Torque
"
Cylinder
head
cover
to
cylinder
head
............
...
.
.10
Nm
(89
in-lb)
CAMSHAFT
TIMINGCHAINS,
6-CYLINDER
Page 115 of 759
119
Lubrication
System
LUBRICATION
SYSTEM
119-1
GENERAL
.
.
.
.
.
.
...
.
.
.
.
.
.
.
...,
,
...
.
.
.
.
119-1
OH
pan,
removing
and
installing
(6-cylinder
engine,
1992
models)
.
.
.
.
.
.
.
.
.
119-4
TROUBLESHOOTING
.
.
.
.
.
.
...
.
.
.
.....
.
119-1
Oil
pan,
removing
and
installing
Oil
pressure,
checking
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
119-1
(6-cylinder
engine,
1993
and
later
models)
.119-6
Oil
pressure
warning
system,
testing
.
.
.
.
.
.
.
119-2
OIL
PUMP
.
.......
.
.............
.119-8
OIL
PAN
.
.
.
.
.
.....
.
.
.
.
.
......
.
.
.
.
.
.
.
..
119-2
Oil
pump,
removing
and
installing
Oil
pan,
removing
and
installing
(4-cylinder
engine)
.
.
.
...
.
..........
.
.
.119-8
(4-cylinder
engines)
.
.
...
.
....
.
.
.
.
.
.
.
..
119-2
Oil
pump,
removing
and
installing
(6-cylinder
engine)
.
.
.....
.
.........
.
.119-10
GENERAL
Oil
pressure,
checking
The
oil
pan
and
the
oil
pump
can
be
removed
with
theen-
gine
installed,
although
engine
liftinglsupport
equipment
is
necessary
.
NOTE-
Oil
change
procedure
and
oil
filter
replacement
are
covered
in
020
Maintenance
Program
.
Al¡
engines
are
equipped
with
an
oil
pressure
warning
sys-
tem
to
help
prevent
engine
damage
.
Other
safety
features
in-
clude
:
"
A
filter
bypass
to
provide
lubrication
should
the
oil
filter
become
clogged
.
"
An
oil
pump
pressure
relief
valve
to
prevent
excessive
system
pressure
.
TROUBLESHOOTING
The
lubrication
warning
system
consists
of
an
oil
pressure
switch
mounted
in
the
oil
circuit
and
an
instrument
panel
warn-
ing
light
.
CAUTION-
If
the
red
oil
pressurewarning
light
comes
on
or
flashes
on
while
driving,
always
assume
that
the
oil
pressure
is
low
.
To
perform
an
oíl
pressure
test,
BMW
specifies
special
tools
that
attach
to
thetop
of
the
oíl
filter
housing
.
The
following
pro-
cedure
works
well
using
standard
automotive
oil
pressure
testing
equipment
attached
to
the
oil
pressure
switch
port
in
the
engine
.
In
some
engines,
however,
access
tothis
port
may
be
extremely
restricted
.
1
.
Disconnect
harness
connector
from
oil
pressure
switch
andremove
switch
.
See
Fig
.
1
.
NOTE-
Thoroughly
clean
around
the
oil
pressure
switchbefore
removing
it
.
Fig
.
1
.
Oil
pressure
switch
location
on
M50
engine
(arrow)
.
TROUBLESHOOTING
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 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 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