Injector BMW M3 1993 E36 User Guide

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

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

Starter,
removing
and
installing

(6-cylinder
engine
with

automatic
transmission)

The
starter
on
a
6-cylinder
car
with
automatic
transmission

ís
removed
from
above
.
It
is
necessary
to
remove
the
íntake

manifold
and
disconnect
a
number
of
electrical
harness
con-

nectors
.

1
.
Disconnect
negative
(-)
battery
cable
.

2
.
Remove
air
plenum
from
rear
of
engine
compartment
.

See640
Heating
and
Air
Conditioning
.

3
.
Remove
top
enginecovers
.
See
Fig
.
9
.

Fig
.
9
.



Remove
top
engine
cover
by
prying
out
plugs
and
removing
nuts
(A)
.
Make
sure
rubber
insulators
(B)
on
either
sideof
large
cover
do
not
fall
off
during
cover
removal
.

4
.
Remove
ignition
coil
harness
connectors
.
Remove
ground
connection
at
front
of
cylinder
head
.

5
.
Remove
two
retaining
bolts
and
lift
off
fuel
injector
har-
ness
connector
strip
.
Carefully
fold
away
all
harnesses
toward
right
side
of
engine
compartment
and
place
at
base
of
windshield
.
See
Fig
.
10
.

6
.
Remove
intake
manifold
.
See
113
Cylinder
Head
Re-
moval
and
Installation
.

7
.
Disconnect
wiring
from
starter
.

BATTERY,
STARTER,
ALTERNATOR



121-
9

Fig
.
10
.
Fuel
injection
harness
(A)
and
ignition
coíl
harness
connectors
(B)
being
lifted
off
engine
to
be
placed
at
base
ofwindshield
.
M50
engine
shown
.
Other
6-cylinder
engines
are
similar
.

8
.
Loosen
and
remove
bolts
and
nuts
fastening
starter
to
transmission
bell
housing
and/or
engine
block
.
Remove

starter
support
bracket
.

Fig
.
11
.
Starter
wiring
terminals
and
support
bracket(arrow)
.
Intake
manifold
has
been
removed
.

STARTER
SERVICE

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

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
.

FUEL
INJECTION



130-
3

Fuel
metering
.
The
ECM
meters
fuel
bychanging
the



The
engine
management
system
compensates
automatical-
opening
time
(pulsewidth)
of
the
fuel
injectors
.
To
ensure
that



ly
for
changes
in
the
engine
due
to
age,
minor
wear
or
small
injector
pulsewídth
is
the
only
factor
that
determines
fuel
me-



problems,
such
as
a
disconnected
vacuum
hose
.
Asa
result,
tering,fuel
pressure
is
maintained
bya
fuel
pressure
regula-



idle
speed
and
mixture
do
not
need
lo
be
adjustedas
partof
tor
.
The
injectors
are
mounted
lo
a
common
fuel
supply
called



routine
maintenance
.
the
fuel
rail
.

The
ECM
monitors
engine
speed
to
determine
the
duration



NOTE-

ofinjector
openings
.
Other
signals
to
the
ECM
help
determine



Poordriveabilitymaybe
encountered
when
the
batteryis

injector
pulse
time
for
different
operating
conditions
.
A
tem-



disconnected
and
reconnected
.
when
the
battery
is
dis-
connected,
the
adaptive
memory
is
lost
The
system
will
perature
sensor
signals
engine
temperature
for
mixture
adap-



readaptafterabout
ten
minutes
of
drfving
.
tion
.
A
throttle
position
sensor
signals
throttle
position
.
The
exhaust
oxygen
sensor(s)
signal
information
about
combus-
tion
efficiency
for
control
of
the
air-fuel
mixture
.
1992
to
1995



DISA
(Dual
Resonance
Intake
System)
engines
are
equipped
with
a
single
sensor
.
1996
and
later
(OBD
II)
engines
are
equipped
with
an
oxygen
sensor
before



TheE36
4-cylinder
engine
is
equipped
with
a
dual
intake
andone
after
each
catalytic
converter
.
Forexample,the
M52



runner
system,
termed
DISA
.
DISA
offers
the
advantages
of
engine
is
equipped
withfour
oxygen
sensors
.



both
short
and
long
intake
pipes
.
Long
intake
runners
are
most
useful
at
low
to
medium
engine
rpm
for
producing
good
Idle
speed
control
.
ldle
speed
is
electronically
controlled



torque
characteristics
.
Short
intake
runners
produce
hígherviathe
idle
speed
control
valve,
which
maintains
idle
speed
by



horsepower
at
hígher
engine
speeds
.
bypassing
varying
amounts
of
air
around
theclosed
throttle
valve
.
Idle
speed
is
not
adjustable
.



NOTE-

Knock
(detonation)
control
.
Knock
sensors
monitor
and



The
term
DISA
comes
from
the
German
words
Differen-

control
ignition
knock
through
the
ECM
.
The
knock
sensors



zierte
Sauganlage,
and
can
roughlybe
translated
as
"dif-
fering
intake
manifold
configuration
."
See
100
Engine-
function
like
microphones
and
are
able
to
convert
mechanical



General
foradditional
information
on
DISA
operation
.
vibration
(knock)
into
electrical
signals
.
The
ECM
is
pro-

grammed
to
react
to
frequencies
that
are
characteristic
of
en-



Manifold
construction
:
The
intake
manifold
is
a
two-piece
gine
knock
and
adapt
the
ignition
timing
point
accordingly
.



metal
construction,
with
a
pair
of
runners
in
thetop
section
See120
Ignition
System
for
further
details
.



and
four
runners
in
the
lower
section
.
A
butterfly
valve
is
in-
stalled
in
the
lower
section,
enabling
the
DISA
solenoid
toiso-

NOTE-



late
one
pair
of
runners
from
the
other
pair
.
See
Fig
.
2
.

The
1992
M50
engine
is
not
equipped
with
knock
sen-



Operation
.
With
the
DISA
butterfly
valve
closed,
the
pipes
sors
.
All
other
engines
are
equipped
with
two
knock



in
thetop
half
of
the
manifold
act
together
with
the
ram
air
sensors
.



pipes
in
the
lower
halfto
producea
single,
long
air
intake
pipe
for
each
cylinder
.
See
Fig
.
3
.
The
column
of
aír
oscíllating
in

Basic
Engine
Settings



this
combined
pipe
significantly
increases
engine
torque
in
the

medium
rpm
range
.

Idle
speed,
idle
mixture
(%CO),
and
ignition
timing
arenot

adjustable
.
The
adaptive
engine
management
system
is
de-

signed
to
automatically
compensate
for
changes
in
engine
op-

eratingconditions,
although
the
adaptive
range
is
limited
.
Once

these
limits
are
exceeded,
driveability
problems
usually
be-

come
noticeable
.

Above
approximately
4,800
rpm,
the
butterfly
valve
between
the
intake
air
pipes
for
the
two
cylinder
groups
is
opened
.
The
shorter
pipes
in
the
lower
manifold
section
now
become
the

main
suppliers
of
ram
air
to
the
cylinders,yielding
greater
pow-

er
at
the
upper
end
of
the
engine
rpm
range
.
See
Fig
.
4
.

Control
components
.
The
DISA
butterfly
valve
is
actuated

NOTE-



electro-pneumatically
via
the
engine
control
module
(ECM)
.

lf
the
system
adaptive
limits
are
exceeded,
the
Check



The
valve
begins
to
open
as
engine
speed
rises
aboye
4,840

Engine
light
will
most
likely
come
on,
indicating
an



rpmand
closes
below
4,760
rpm
.
The
action
of
the
valve
is
de-
emissions-
related
fault
For
Check
Engine
light
diag-



liberately
delayed
to
prevent
it
from
opening
and
closing
repeat-
nostics,
see100
Engine-General
.



edly
within
a
short
time
.

GENERAL

3
.
Observe
fuel
pressure
gauge
after
20
minutes
.
The

pressure
shouldnot
drop
off
more
than
0
.5
bar
from

system
pressure
listed
in
Tablec
.

4
.
When
finished
testing,
disconnect
pressure
gauge
and
reconnect
fuel
line
.

If
the
fuel
system
does
not
maintain
pressure,
check
visual-
¡y
for
leaks
in
fuel
lines
orat
unions
.
Leaks
can
also
be
due
to
a
leaking
injector
or
a
faulty
fuel
pump
check
valve
.
Check
the

pump
check
valve
by
repeating
the
test,
butbefore
turning
the

fuel
pump
off,
pinch
off
theretum
line
at
the
fuel
rail
.
If
the

pressure
is
now
maintained,
the
fault
is
most
likely
the
fuel

pump
check
valva
.

Tabla
c
.
Fuel
Pressure
Specifications

Engine



1
Fuel
pressure

4-cytinder



1
3
.0
t
0
.2
bar
(43
.5
t
2
.9psi)

6-cytinder
M50/S50US
engine



3
.0
t
0
.2
bar
(43
.5
±2
.9psi)
M52/S52US
engine



3
.5
f
0
.2
bar
(51
t
2.9psi)

Fuel
pressure
regulator
response

to
engine
load,
testing

1
.
With
fuel
pressure
gauge
connected,
reinstallfuel

pump
relay
.
Start
engine
and
allow
it
to
idle
.

NOTE-

The
fuel
pressure
should
be
lower
by0
.4-0.7
bar
from
the
specifications
listed
in
Table
c
.
Engine
vacuum
act-
ing
on
the
fuel
pressure
regulator
diaphragm
reduces
the
fuel
pressure
.

2
.
With
engine
idling,
remove
vacuum
hose
from
regula-

tor
.
Pressure
should
increase
.

3
.
Reconnecthose
and
check
that
pressure
decreases
.

4
.
When
finished
testing,
disconnect
pressure
gauge
and

reconnect
fuelline
.
Tighten
hose
clamp
.



0013190

Fig
.
13
.
For
electrical
tests,
4-cytinder
fuel
injector
harnessduct
can
be

If
fuel
pressure
does
not
drop
with
the
vacuum
hose
con-



accessed
between
intake
manifold
and
cytinder
head
cover
.

nected
and
no
faulty
are
found
with
fuel
the
pressure
regulator

vacuum
hose,
the
fuel
pressure
regulator
is
faulty
.



1
.
Check
that
ECM
signal
is
present
atinjector
connector
.

NOTE-

A
cracked
or
leaktng
pressure-regulator
vacuum
hose

may
cause
en
erratic
tdle
.

FUEL
INJECTION



130-
11

Fuel
rail
and
injectors,
checking

The
fuel
injectors
are
switched
on
and
off
(opened
and
closed)
by
the
ECM
.
The
injectors
are
connected
to
a
com-
mon
fuel
supply,
callad
the
fuel
rail
.

The
fuel
injectors
are
removed
by
first
removing
the
com-
plete
fuel
rail
assembly
and
then
unclipping
the
injectors
from
the
fuel
rail
.

CA
UTION-

Use
only
a
digital
multimeter
or
an
LED
injector
tester
when
testing
injectors
or
wiring
.
Use
of
ananalog
VOM
or
incandescent
testlight
may
dam-
age
the
engine
control
module
.

NOTE-

"
On
4-cytindercars
pry
up
the
injector
wiring
duct
and
then
pry
off
the
cover
.
See
Fig
.
13
.

"
On
6-cytinder
cars
it
is
necessary
to
remove
the
top
engine
cover(s)
to
access
the
fuel
rail
and
injectors
.

"
Back
probe
injector
harness
connector
using
digital

voltmeter
.
See
Fig
.
14
.

"
Operate
starter
or
run
engine
and
check
for
pulsad

voltage
signal
.
"
Repeat
for
each
injector
.

NOTE
-

To
quick-check
if
en
injectorfunctioning,
place
a
screw-
driver
or
stethoscope
on
the
injector
with
the
engine

running
.
If
the
injector
is
operating,there
should
been

audible
buzz
.

FUEL
DELIVERYTESTS

130-
1
2



FUEL
INJECTION

Fig
.
14
.
Voitmeter
connected
across
fuel
injector
connector
with
en-
gine
running
.
M50
engine
shown
.

2
.
If
no
signal
is
present,
check
for
b+
power
to
injectors
.
There
should
be
battery
voltage
(+)
at
red/whitewire
of

each
injector
connector
with
the
ignition
key
on
.
If
volt-

age
is
not
present,
check
main
relay
output
.
Injector
b+

power
comes
from
main
relay
(terminal
87)
.

NOTE-

If
there
is
positive
(+)
batteryvoltage
at
injectors
but
there
was
no
pulsedresponse
at
voltmeter,
check
the
wire(s)
from
the
ECM
to
the
injectors
.
If
no
wiring
faults
can
be
found,
the
pulsed
ground
signal
from
the
control
module
may
be
missing
.
Check
the
outputs
from
the
ECM
.

Fuel
rail
and
injectors,
replacing

1
.
Disconnect
negative
(-)
battery
cable
.

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
tront
of
this
manual
on
page
viii
.

2
.
M42
and
M50/S50US
engines
:
Working
at
end
offuel
rail,
disconnect
small
vacuum
hose
from
fuel
pressure
regulator
.

3
.
M50/S50US
engines
:
Remove
two
nuts
from
injector

duct
.
Carefully
pry
injector
wiring
duct
off
ínjectors
.
See
Fig
.
15
.

4
.
On
4-cylinder
cars,
remove
upper
intake
manifold
to
ac-
cess
the
fuel-rail
and
injectors
.
See
113
Cylinder
Head
Removal
and
Installation
.

FUELDELIVERYTESTS

Fig
.
15
.
Injector
wiring
harness
duct
being
removed
from
M50
engine
.

NOTE
-

Late-model
M42
and
all
M44
fuel
injectors
are
afr-
shrouded
.
See
Fig
.
16
.
When
removing
the
fuel
rail
it
is
necessary
to
remove
the
air
shroud
feeder
hose
from
the
intake
manifold
ducting
.

Fig
.
16
.
Cutaway
view
of
fuelinjector
usedon
M42
or
M44
engine
.

5
.
Disconnect
fuel
supply
line
and
fuel
retum
line
from
fuel
rail
ends
.

WARNING
-

"
Clamp
off
the
fuel
lines
and
then
wrapa
clean
shop
towei
around
the
lines
before
removing
them
.
Residual
fuel
pressure
is
present
in
the
lines
.

"
Fuel
will
be
discharged
.
Do
not
disconnect
any
wires
that
could
cause
electrical
sparks
.
Do
not
smoke
or
worknear
heaters
or
other
fire
hazards
.
Keepan
approved
fire
extinguisher
handy
.

6
.
Remove
fuel
rail
mounting
bolts
.
See
Fig
.
17
.

0012504

Fig
.
17
.
Location
of
fuel
rail
mounting
bolts
(A)
and
fuel
inlet
and
return
lines
(B)
on
M44
engine
.
Upper
manifold
has
been
removed
.

7
.
Pull
upon
fuel
rail
and
remove
injector
rail
with
injec-tors
.
Remove
individualinjectors
by
removing
injector

retaining
clip
and
pullinginjector
from
rail
.
See
Fig
.
18
.

Fig
.
18
.
Pry
retaining
clip
from
injector
(1),
then
pull
injector
from
rail
(2)
.

8
.
Installation
is
reverse
of
removal
.

Tightening
Torque

"
Fuel
rail
to
cylinder
head
..
.
..
..
...
10
Nm
(89
in-lb)

FUEL
INJECTION



130-
1
3

Fuel
Pressure
Regulator

The
fuel
pressure
regulator
location
on
E36
models
is

mounted
in
one
of
two
locations
:

Fuel
Pressure
Regulator
Location

"
4-cylinder
engines

1992-
January
1997
............
...
..
on
fuel
rail

January
1997-
on
...............
..
...
under
car

"
6-cylinderengines

1992-1995
.
.
...
...
.
...........
...
..
on
fuel
rail

1996-on
..
.
..
................
...
...
undercar

Fuel
pressure
regulator,
replacing

(fuel
rail
mount)

WARNING
-

Fuel
will
be
discharged
.
Do
not
disconnect
any
wires
that
could
cause
electrícal
sparks
.
Do
not
smoke
or
work
near
heaters
or
other
fire
hazards
.
Keepan
approved
fire
extinguisher
handy
.

9
.
On
6-cylinder
engines,
remove
top
engine
covers
.
Re-
move
fuel
rail
mounting
bolts
and
lift
up
fuel
rail
.

1
.
Disconnect
vacuum
hose
from
fuel
pressure
regulator
.

See
Fig
.
19
.

"
Fit
new
O-rings
when
installing
injectors
.
For
ease
of

installation,
lightly
lubricate
O-rings
with
SAE
90
or



0012732

equivalent
lubricant
.



Fig
.
19
.
Fuel
pressure
regulator
(arrow)
on
M42
engine
.
Vacuum
hose

"
Check
that
injector
electrical
connections
are
correctly



shown
at
A
.

fitted
and
that
injectors
are
fully
seated
prior
to
install-

ing
fuel
rail
mounting
bolts
.



2
.
Remove
bolt
from
regulator
clamp
.
Remove
clamp
.
Note

"
Replace
wire
ties
.



installed
direction
of
regulator
to
fuel
rail
.

3
.
Wrap
a
shop
rag
around
regulator,
then
remove
regula-

tor
from
fuel
rail
by
pulling
straight
out
.

FUELDELIVERYTESTS

NOTE-



NOTE-
"
The
Ole
speed
control
valve
signal
can
be
checked



The
intake
manifold
is
held
in
place
with
7
nuts
from
using
a
duty
cycle
meter
(or
dwellmeter)
.
Connect
the



above
and
2
support
bracket
bolts
from
undemeath
.
On
meter
to
the
valve
following
the
manufacturer's
in-



DME
3
.1
cars,
carefully
disconnect
the
idleair
hose
from
structions
.
Turn
on
the
WC
or
create
a
larga
air
leak



theintake
manifold
when
lifting
the
manifold
off
.
For
more
and
check
that
the
meter
reading
reacts
while
the
idle



information,
sea
113
Cylinder
HeadRemovaland
In-
speed
remainssteady
.



stallation
.

"
There
are
some
additional
inputs
to
the
control
mod-
ule
that
affect
idle
speed
(Le
.
throttle
position,
AIC-on



5
.
Disconnect
al¡
necessary
hoses
andremove
idle
speed
signals,
andAIT
Drive
position)
.
Check
these
signals



control
valve
.
if
idle
problems
persist
.
See
Tabla
i
orTable
j
.

Idle
speed
control
valva,
replacing

The
idle
speed
control
valve
is
mounted
beneath
the
intake
manifold
.
Accessing
the
valva
is
best
accomplishedby
first
re-
moving
the
intake
manifold
.

NOTE-

¡tis
recommended
that
the
intake
manifold
gaskets
be
replaced
whenever
the
intake
manifold
is
removed
.

1
.
Remove
top
enginecovers
from
engine
.
See
Fig
.
31
.

FUEL
INJECTION



130-21

6
.
Installation
is
reverse
of
Removal
.
Use
new
gaskets
when
installing
intake
manifold
.

NOTE-

Poor
driveability
may
be
noticed
afterinstalling
a
re-
placement
idle
speed
control
valve
.
After
about
10
min-
utes
of
driving,
the
system
will
adapt
the
base
setting
of
the
valva
and
the
idle
speed
should
retum
to
normal
.

Tightening
Torque

"
Intakemanifold
to

cylinder
head
(M7)
........
..
.
15±2
Nm
(11
ti
ft-Ib)

BOSCH
DME
M5
.2

COMPONENT
REPLACEMENT

On-Board
Diagnostics
11
(OBD
II)
is
incorporated
into
the

Bosch
DME
M5
.2
engine
management
systems
used
on
the

M44
engine
.
OBD
II
is
capable
of
detecting
a
full
range
of

faults
.
When
faults
are
detected,
a
Diagnostic
Trouble
Code
(DTC)
is
stored
in
the
system
ECM
.
The
Check
Engine
warn-
ing
light
will
also
come
on
if
an
emissions-relatad
fault
is
de-
tected
.

The
most
efficient
way
to
diagnose
the
Bosch
OBD
II
sys-

tem
is
by
using
a
specialized
scan
tool
.
The
OBD
II
system
is

capable
of
storing
hundreds
of
faults,
making
diagnostics
with

a
scan
tool
the
only
viable
method
.
Therefore,
system
diag-
nostics
is
not
covered
here
.

Fi



31
.
Remove
to
en
ine
covers
b



in
out
caPs
and
removin



NOTE-

nuts
(A)
9
.



P



g



y
Pry
g



g



"
The
OBD
11
fault
memory
(including
an
iiluminated
Note

14


L-te
at
cover
edge
(arrows)
.
Check
Engine
light)
can
only
be
reset
using
the
spe-
cial
scan
tool
.
Removing
the
connector
from
the
ECM
2
.
Remove
two
hold
down
nuts
from
fuel
injector
wiring



or
disconnecting
the
battery
will
not
arase
the
fault
duct
.
Pry
back
injector
connector
retainers
and
lift
off



memory
.

wiring
duct
.



"
The
16-pin
OBD
Il
diagnostic
connector
is
located
on
the
lower
left
dash
panel
.
Refer
to
Fig
.
1
.
3
.
Disconnect
intake
air
bootfrom
throttle
housing
.
Where

applicable
disconnect
accelerator
cable
and
cruise



"
BMW
special
scan
tool
ora
`generic"OBD
II
scan
tool

control
cable
from
their
brackets
.



must
be
used
to
access
DTCs
.

4
.
Unbolt
intake
manifold
and
move
it
out
of
way
enough

to
access
idle
speed
control
valva
.

"
Tablak
lists
engine
control
module
(ECM)
pinouts
for
the
DMEM5
.2
system

BOSCH
DME
M5
.
2
COMPONENT
REPLACEMENT