Ignition system BMW 323i 1995 E36 Service Manual

^1
.5WT
^1
.5RD
^1
.5YL
^1
.5BL
r



--__



____-



__-_



___-_



-___-_____--__--



-____-___



____-
i
26
g
5022
23



54



5

I



Power
input



power
input
I



Engine
Control
Module
(Bosch
DME
M5
.2)



I
I



grounds



I
P
owerinput



Main
relay
control



I
70
40



71



21



2078



34
55
626



27
----------------------
-
---------
-
--
-
------------
-
-----------
.,



v
1
1
.1



v
`
1
35BK



35BK

2
(



1Y



¡3



194

Knock
Sensor
Knock
Sensor
(cyl
.1-2)
(cyl
.3-4)

Frommain
relay
terminal
87
(battery
voltage
in
run
or
start

Battery
voltage
in
run
or
start
(
via
ignition
switch



Warnin
terminal
15)



Lethal
óltage



WIRING
present



COLOR
CODE
2
.5
GN



'

1
.0
YL



/
1
.0
BL



/
1
.0
RDNJT

.35
BK
/



/
.35
BK

Camshaft
Position
Sensor
-_

Fig
.
14
.
Bosch
DME
M5
.2
ignition
system
circuit
for
M44
engine
.

Ground
(RH
rear
of
engine
compartment,
rearof
shock
tower)

Crankshaftirpm
Position
Sensor

IGNITION
SYSTEM



120-9

Batteryvoltage



Battery
voltage
in
run
or
start



in
run
or
start
(via
main
relay



(
via
ignition
switch
terminal
87)



terminal
15)

BK
-
BLACX
BR
-
BROWN
RD
-
RED
YL
-
YELLOW
GN
-
GREEN
BL
-
BLUE
VI
-
VIOLET
GY
-
GREY
WT
-
WHITE
PK
-
PINK

Battery
voltage
at
all
times
to
Main
relay
(terminal
85)

Ground
(RH
rear
of
engine
compartment,
rearof
shock
tower)



0012721

lGNITION
SYSTEM
SCHEMATlCS

120-10



IGNITION
SYSTEM

Ground
(rear
of
engine
compartment,
rear
of
passenger
side
shock
tower)

.!
BK

Camshaft
Position
Sensor

IGNITION
SYSTEM
SCHEMATICS

Batteryvoltage
in
run
or
start
(
via
ignition
switch
terminal
15)

---------------------------------------------------------
55



S5154
i

power
input



Power
input



1
DME
Control
Module(Bosch
DME
M3
.1)

Ground
-
(RHrear
of
enginecompartment,
rearof
passenger
side
shock
tower)

Fig
.
15
.
Bosch
DME
M3
.1
usedon1992
M50
engines(without
VANOS)
.

.EBK

Crankshaftlrpm
Position
Sensor

5GN

1.0
RD

Ground
(RH
rearof
enginecompartment,
rear
of
passenger
side
shock
tower)

WIRING
COLOR
CODE

BK
-
BLACK
BR
-
BROWN
RD
-
RED
YL
-
YELLOWGN
-
GREEN
BL
-
BLUE
VI-
VIOLET
GY
"
GREY
WT
"
WHITE
PK
-
PINK

Batteryvoltage
in
run
or
start
(
via
main
relay
Battery
voltage



terminal
87)
in
run
or
start
(via
ignition
switch
terminal
15)

11508

1
grounds



Main
rela
control
P
ower
Input



Y



I
-
34
---"--
6
26
27
1

Battery
voltage
at
all
times
to
Main
relay
(terminal
85)

RER

Knock
Sensor
Knock
Sensor
(cyl
.1-3)
(cyl
.4-6)

Batteryvoltage



IMIRING
in
run
or
start



COLORCODE
(
via
ignition
switch
termina¡
15)



BK



BLAOK
BR
BROWN
RD
-
RED
YL
-
YELLOW
GN
"
GREEN
EL
-
BLUF
VI
-
VIOLET
GY
-
GREY
WT
-
WHITE
PK
-
PINK
4
.0
GN

l1/1j\
I'1
/~/1r1



l\r1

1
55



so



si



52



23



25



24



56



54
1
Power
input



Power
input



III



O
Engine
Control
Module
(Bosch
DMEM13
.1)



II



grounds



P
ower
input



Main
relaY
control
I
70
__
_
71



69



17



28



43



16



-34---"-6



26



27
____________________________________________

From
main
relaterminal
87
(battery
voltage
in
run
or
start

.5
YL

Camshaft
Position
Sensor

Ground
(RH
rearof
enginecompartment,
rear
of
shock
tower)

.5
BK

Crankshaft/rpm
Position
Sensor

Fig
.
16
.
Bosch
DME
M33
.1
ignition
system
círcuit
for
1993-1995
M50
engines
with
VANOS
.

IGNITION
SYSTEM



120-11

Ground
=
(RH
rear
of
engine
compartment,
back
sideof
shock
tower)

Batteryvoltage



Battery
voltage
in
run
or
start



in
run
or
start
(
via
ignition
switch



(
via
main
relay
terminal
15)



terminal
87)

1
.0
RD

11506a

.5
BR

Batteryvoltage
at
all
times
to
Main
relay
(terminal
85)

IGNITION
SYSTEM
SCHEMATICS

120-12



IGNITION
SYSTEM

Warning
.
Lethal
voltagepresent

Battery
voltage
in
run
or
start
(via
ignitíon
switch
terminal
15)

I
t

IGNITION
SYSTEM
SCHEMATICS

Battery
voltage
in
run
or
start
(
via
ignition
switchterminal
15)



WIRING
COLOR
CODE

Knock
Sensor
Knock
Sensor



Crankshaftlrpm



Camshaft
(cyl
.
1-3)



(cyl
.
4-6)



Position
Sensor



Position
-
-
Sensor
-

Fig
.
17
.
Siemens
MS
41
.1
ignition
systemusedon1996
and
later
6-cylinder
engines
.

1.0
BR

PQ

1
.08~1
.0BKIRD



/1
.0BK/YL



'10BK/BL



'1
.03KIGN



10BKNI
4
1D

BK
-
BLACK
BR
-
BROWN
RD
-
RED
YL
-
YELLOW
GN
-
GREEN
BL
-
BLUE
VI-
VIOLET
GY
-
GREY
WT
-
WHITE
PK
-
PINK

Batteryvoltage
in
run
or
start
(via
main
relay
terminal
87)

!1



rl
1.0
B~



^
1.0
BK/RD



^
1.0
BKIYL



^
1
.0
BK/BL



n
1.0
BK/GN



n
1
.0
BKIVI



%~
r
-------
--------------_____________----_______-_-____
49



29



1



30



2



31



3



8754
1
power
input



Power
input



I
1



Engine
Control
Module
(Siemens
MS
41
.1)



1
1



grounds



1
n
1



Powerinput
Mainrelaycontrol
1
1-
57

___
58



_
59
_
__
63
_



38



83



48



40



64



43



65



41



28



32



34



4



26



73



1
-



-----------
-
_-----
-
------
_
------
-
------
-
---



-

.5Y1-



.5BKY.5GNY.5BRY
Y



.35BKY
1
Y



Y



.35BKY/Y35YY
75
.18R/
.5YL-1
1'
.

Batteryvoltage
at
all
times
to
Main
relay
(terminal
85)

Ground



v
(RH
rear
of
engine



Z
compartment,
rear



=
of
shock
tower)



Ground
(RH
rear
of
enginecompartment,
rearof
shock
tower)



0012731

121-2



BATTERY,
STARTER,
ALTERNATOR

CHARGING
SYSTEM
TROUBLESHOOTING



Static
currentdraw,
checking

Charging
system
diagnostics
requires
special
test
equip-

ment
.
If
the
test
equipment
is
not
available,
charging
system

fault
diagnosis
can
be
performedby
an
authorized
BMW
deal-

eror
other
qualified
repair
shop
.
A
general
troubleshooting

guide
is
given
in
Table
a
.

Charging
System
Quick-Check

As
a
quick-check,
use
a
digital
multimeter
lo
measure
volt-



2
.
Disconnect
battery
negative
(-)
cable
.

age
across
the
battery
terminals
with
the
key
off
and
then

again
with
the
engine
running
.
The
battery
voltage
should
be



CAUTION-
about12
.6
volts
with
key
off
and
approximately
14
.0
volts
with



Prior
to
disconnecting
the
battery,
read
the
battery
the
engine
running
.
If
the
voltage
does
not
increase
when
the



disconnection
cautions
given
at
the
front
of
this
engine
is
running,there
is
a
fault
in
the
charging
system
.



manual
onpaga
viii
.

NOTE
-

The
regulated
voltage
(engine
running)
should
be
be-
tween
13
.5
and
14
.5,
depending
on
temperatura
and
operating
conditions
.
If
the
voltage
is
higher
than
14
.8,
the
voltage
regulator
is
most
Mely
faulty
.

Check
for
clean
and
tight
battery
cables
.
Check
the
ground

cable
running
from
the
negative
(-)
battery
terminal
lo
the

chassis
and
the
ground
cable
running
from
the
engine
lo
the

chassis
.
Check
the
alternator
drive
belt
condition
and
tension
.

If
the
battery
discharges
over
time,
there
may
be
a
constant

drain
or
current
draw
on
the
battery
.
A
small
static
drain
on
the

battery
is
normal,
but
a
largedrain
will
cause
the
battery
lo

quickly
discharge
.
Make
a
static
current
draw
test
asthe
first

step
when
experiencing
battery
discharge
.

1
.
Make
sure
ignition
and
al¡
electrical
accessories
are

switched
off
.

3
.
Connect
a
digital
ammeter
between
negative
battery

post
and
negative
battery
cable
lo
measure
current
.

See
Fig
.
1
.
Wait
at
least
one
minuta
lo
get
an
accurate

reading
.

A
range
of
about
0
lo
100
milliamps
is
normal,
dependingon

the
number
of
accessories
that
need
constant
power
.
A
current

of
400
milliamps
(0.4
amp)
or
more
may
indicate
a
problem
.

Table
a
.
Battery,
Starter
and
Charging
System
Troubleshooting

Symptom



1



Probable
Cause



1



Correctiva
Action

1
.
Engine
cranks
slowlyor
not



a
.
Battery
cables
loose,
dirty
orcor-



a
.
Clean
or
replace
cables
.
See020
Maintenance
Program
.
a
tall,
solenoíd
clicks
when



roded
.
starter
is
operated
.



b
.
Battery
discharged
.



b
.
Charge
battery,
test
and
replace
if
necessary
.
c
.
Body
ground
straploose,
dirty
or



c
.
Inspect
ground
strap,
clean,
tighten
or
replace
if
necessary
.
corroded
.
d
.
Poor
connection
at
starter
motor



d
.
Check
connections,
test
for
voltage
at
starter
.
Test
for
voltage
at
terminal
30
.



neutral
safety
or
clutch
interlock
switch
.
e
.
Starter
motor
or
solenoid
faulty
.



e
.
Test
starter
.

2
.
Battery
will
not
stay



a
.
Short
circuit
draining
the
battery
.



a
.
Test
for
excessive
current
drainwith
everything
electrical
in
the
charged
more
than
a
few



vehicle
off
.
days
.



b
.
Short
driving
trips
and
high
elec-



b
.
Evaluate
driving
style
.
Where
possible,
reduce
electrical
con
trical
drain
on
charging
system



sumption
when
making
short
trips
.
does
not
allow
battery
to
re-
charge
.
c
.
Drive
belt(s)
worn
or
damaged
.



c
.
Inspect
or
replace
multi-ribbed
belt(s)
.
See
020
Maintenance
Program
.
d
.
Battery
faulty
.



d
.
Test
battery
and
replace
íf
necessary
.
e
.
Battery
cables
loose,
dirty
orcor-



e
.
Clean
or
replace
cables
.
See
020
Maintenance
Program
.
rodad
.
f
.
Alternatoror
voltage
regulator



f
.
Test
alternator
and
voltage
regulator
.
faulty
.

3
.
Battery
losing
water
.



1
a
.
Battery
overcharging
.



1
a
.
Test
voltage
regulator
for
proper
operation
.

4
.
Lights
dim,
light
intensity



a
.
Drive
belt(s)
worn
or
damaged
.



a
.
Inspect
or
replace
multi-ribbed
belt(s)
.
See
020
Maintenance
varies
with
engine
speed
.



Program
.
b
.
Alternatoror
voltage
regulator



b
.
Test
alternator
and
voltage
regulator
.
faulty
.
c
.
Body
ground
straps
loose,
dirty
or



c
.
Inspect
ground
straps,
clean,
tighten
or
replace
as
necessary
.
corroded
.

CHARGING
SYSTEM
TROUBLESHOOTING

121-
4



BATTERY,
STARTER,
ALTERNATOR

BatteryOpen-Circuit
Voltage
Test



Battery
Charging

Before
making
the
test,
load
the
battery
with
15
amperes
for



Discharged
batteries
can
be
recharged
using
a
battery

one
minute
with
a
batteryload-tester
or
turn
on
the
headlights



charger
.
The
battery
should
be
removed
from
the
luggage

for
about
one
minute
without
the
engine
running
.Then
discon-



compartment
during
charging
.

nect
the
battery
negative
(-)
cable
and
connect
a
digital
volt-

meter
acrossthe
battery
terminals
.
Open-circuit
voltage



Prolonged
charging
causes
electrolyte
evaporation
to
a
lev

levels
are
given
in
Table
c
.



el
that
can
damage
the
battery
.
Itis
bestto
use
a
low-current

charger
(6
amperes
or
less)
to
prevent
battery
damage

If
the
open-circuit
voltage
ís
OK
butthe
battery
still
lacks



caused
by
overheating
.

power
for
starting,
make
a
load
voltage
test
.
If
the
open-circuit

voltage
is
below
12
.4
volts,
recharge
the
battery
and
retest
.



WARNING
-

Hydrogen
gas
given
off
by
the
battery
duringcharg-

Table
c
.
Open-Circuit
Voltage
and
Battery
Charge



ing
is
explosive
.
Do
not
smoke
.
Keep
open
llames

away
from
the
top
of
the
battery,
and
prevent
elec
Open-circuit
voltage



State
of
charge



trical
sparks
by
turning
offthe
battery
charger
be-

12
.6
V
or
more



Fully
charged



fore
connecting
or
disconnecting
it
.

12
.4
V



1



75%
charged

12
.2
V



50%
charged



CAUTION-

12
.0
V



25%
charged



"
Battery
electrolyte
(sulfuric
acid)
can
damage
the
car
.
If
electrolyte
isspilled,
clean
the
area
11
.7
V
or
less



Fully
discharged



with
a
solution
of
baking
soda
and
water
.

Battery
Load
Voltage
Test

A
battery
load
tester
is
required
for
a
load
voltage
test
.
The



-
Always
disconnect
both
battery
cables
and
re-

test
is
made
by
applying
a
high
resistive
load
to
the
battery
ter-



move
battery
from
vehicle
during
battery
charg-
ing
.
Do
not
exceed
16
.5volts
at
the
battery
.
minals
and
then
measuring
battery
voltage
.
The
battery
should

be
fully
charged
for
the
most
accurate
results
.
The
battery
ca-

bles
mustbe
disconnected
before
making
the
test
.
If
the
volt-



ALTERNATOR
$ERVICE
age
is
below
that
listed
in
Table
d,
the
battery
should
be

replaced
.

WARNING
-

Always
wear
protective
goggles
and
clothing
when
performing
aload
test
.

Table
d
.
Battery
Load
Test-Minimum
Voltage

(apply
200
amp
load
for
15
seconds)

Ambient
temperature



Voltage

80°F
(27°C)



9
.6
V

60°F
(16°C)



9
.5
V

40°F
(4°C)



9
.3
V

20°F
(-7°C)



8
.9
V

0°F
(-18°C)



8
.5
V

ALTERNATOR
SERVICE

"
Always
allow
a
frozen
battery
to
thaw
before
at-
tempting
to
recharge
it
.

Before
checking
the
alternator
and
regulator,
make
sure
the

battery
is
fully
charged
and
capable
of
holding
acharge
.
Check
that
the
battery
terminals
are
clean
and
tight
and
the
al-

ternator
drive
belt
is
properly
tensioned
and
not
severely

worn
.

Charging
system,
checking

CAUTION-

Do
not
disconnect
the
battery
while
the
engine
is
running,
.
Damage
to
the
alternator
andlorengine
electronic
systems
may
result
.

1.
Turn
ignition
key
on
.
Check
that
the
chargewarning

lamp
comes
on
.

NOTE-

If
the
warning
light
does
not
come
on,
repair
any
wiring
or
bulb
faults
before
continuing
to
check
the
charging
system
.

Alternator
brushes,



STARTER
SERVICE
inspecting
and
replacing

Regulator
brushesarenot
available
as
replacement
parts
from
BMW
.
Replacement
brushes
may
be
available
from
af-

termarket
sources,
however
.

1
.
Remove
voltage
regulator
as
described
above
.

2
.
Clean
brush
contact
sürfaces
and
measure
brush
pro-trusion
.
See
Fig
.
7
.

Check
for
battery
voltage
at
terminal
50
of
the
starter
motor
Fig
.
7
.



Regulator
brush
protrusion
(A)
.



with
the
key
in
the
start
position
.
See
Fig
.
8
.
If
voltage
is
not
present,
check
the
wiring
between
the
ignition
switch
and
the
starter
terminal
.
If
voltage
is
present
and
no
other
visible
wir
Voltage
Regulator



ing
faults
can
be
found,
the
problem
is
most
likely
interna¡in

"
Brush
protrusion
(minimum)
.......
.
..
5
mm
(
1
/4
in
.)



the
starter
motor
.

3
.
To
replace
brushes,
carefully
and
as
quickly
as
possi-

ble,
unsolder
brush
lead
from
brush
holder
termina¡,

withdrawing
brush
from
holder
at
same
time
.

4
.
Remove
any
traces
of
solder
frombrush
holder
termi-
nal
using
solder
wick
.

5
.
Fit
spring
into
brush
holder
and
inserí
new
brush
.

6
.
Guide
brush
lead
into
terminal
and
solder
into
place
.

Check
for
free
movement
of
brushes
when
solder

cools
.

7
.
Check
brush
slip
rings
in
alternator
for
wear
.
Lightly
clean
slip
rings
using
fine
abrasive
cloth
.

BATTERY,
STARTER,
ALTERNATOR



121-
7

Starter
Troubleshooting

If
the
starter
tucos
the
engine
slowlyor
fails
to
operate
when
the
ignition
isin
the
start
position,
check
the
battery
first
.
In-
spect
the
starter
wires,
terminals,
and
ground
connections
for
good
contact
.
In
particular,
make
sure
the
ground
connections
between
the
battery,
the
body
and
the
engine
are
completely
clean
and
tight
.
If
no
faults
can
be
found,
the
starter
may
be
faulty
and
should
be
replaced
.

NOTE
-

"
Starting
in1194,
a
factory-installed
drive-away
protec-
tion
system,
alsoreferred
to
as
EWS
or
EWS
11,
was
used
on
all
E36
cars
.
This
system
prevenís
operation
of
the
starter
when
the
system
is
engaged
.
See
515
Central
Locking
and
Anti-theft
.

"
On
cars
with
automatic
transmission,
a
starter
relay
and
a
neutral
safetyswitchare
used
to
present
theen-
ginefrom
starting
in
gear
positions
other
than
park
or
neutral
.
ff
voltage
is
not
present
atterminal
50
with
the
key
in
the
startposition,
check
these
components

To
make
the
most
accurate
check
of
the
battery
cables
and
starterwiring,
make
a
voltage
drop
test
on
the
cables
and
wir-

ing
as
described
in
600
Electrical
System-General
.

Terminal
30
'
\



/
Terminal
30h

0012518

8
.
Reinstall
regulator
and
alternator
.



Fig
.
8
.



Typical
starterwiring
terminal
identification
.
Large
wireat
ter-
minal
30
is
direct
battery
voltage
.
Smaller
wire
at
terminal
50
operates
starter
solenoid
via
ignition
switch
.

STARTER
SERVICE

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

130-
4



FUEL
INJECTION

Main
Relay

Fig
.
2
.



DISA
system
components
.
DISA
is
controlled
via
theengine
control
module
(ECM)
.

Fig
.
3
.



DISA
manifold
runners
with
butterfly
valve
closed
for
lowrpm-
high
torque
operation
.

yje
q

GENERAL

high
power
operation
.

0012734

Fig
.
4
.



DISA
manifold
runners
with
butterfly
valve
open
for
high
rpm-

On-Board
Diagnostics
(OBD)

and
Fault
Diagnosis

Poor
driveability
may
have
a
variety
of
causes
.
The
fault

may
He
withthe
ignition
system,
the
fuel
system,
parts
ofthe

emission
control
system,
ora
combination
of
thethree
.
Be-

cause
of
these
interrelated
functions
and
their
effects
on
each
other,
it
is
often
difficult
to
know
where
to
begin
looking
for

problems
.

For
this
reason,
effective
troubleshooting
should
always
be-

gin
with
an
interrogation
of
the
On-Board
Diagnostic
(01313)

system
.

The
OBD
system
detects
certain
emissions-related
engine

management
malfunctions
.
When
faults
are
detected,the

OBD
system
storesa
Diagnostic
Trouble
Code
(DTC)
in
the

system
ECM
.
In
addition,
the
Check
Engine
warning
light
will

come
on
if
an
emissions-related
fault
is
detected
.

Two
generations
of
OBD
are
used
on
thecars
covered
by
this
manual
.
See
100
Engine-General
for
OBD
I
information

and
fault
codes
.

On-Board
Diagnostics

"
1992-1995models
....
.
...
...
.
...
......
OBD
I

"
1996-1998models
....
.
..
.
.
.
..
...
......
OBD
II