1994 BMW 325i automatic

110-
4



ENGINE
REMOVAL
AND
INSTALLATION

Engine,
removing
and
installing

(6-cylinder
engines)

Engineremoval
procedures
for
the
various
6-cylinder
en-

gines
arecovered
in
this
section
.
Most
steps
in
theproce-

dures
are
similar
or
the
same
for
al¡
engines
.
Specific

differences
that
apply
are
noted
at
the
beginning
of
each
step
.

Be
sure
to
cover
all
painted
surfaces
before
beginning
the

removal
procedure
.
As
an
aid
to
installation,
label
all
compo-

nents,wires,
and
hoses
before
removing
them
.
Do
not
reuse

gaskets,
O-rings
or
seals
during
reassembly
.

WARNING
-

Due
to
risk
of
personal
injury,
be
sure
the
engine
is
cold
before
beginning
the
removalprocedure
.

1
.
Disconnect
negative
(-)
battery
cable
in
luggage
com-

partment
.

CAUTION-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
vi¡¡
.

2
.
Remove
engine
hood
or
place
hood
in
service
position
.

See410
Fenders,
Engine
Hood
.

NOTE-

1t
is
not
necessary
to
remove
the
engine
hood,
but
it
is
helpful
and
will
make
engine
removal
and
installation
easier
.

3
.
Remove
splash
guardunder
engine,
if
applicable
.

4
.
Remove
transmission
from
car
.
See
230
Manual

Transmission
or
240Automatic
Transmission
.

5
.
Remove
vacuum
hosefrom
brake
booster
on
bulkhead
.

Cover
hole
in
booster
and
plug
hose
end
.

6
.
Remove
intake
air
plenum
panel
in
rear
of
engine
com-
partment
.
See
640
Heating
and
AirConditioning
.

7
.
Remove
ground
strap
from
timing
case
cover,
if
appli-

cable
.

8
.
Remove
top
enginecovers
and
disconnect
ignition
coil
harness
connectors
.
Working
at
fuel
injectors,
pry
open
small
wire
clipsat
each
injector
.
Remove
main
harness

hold-down
nuts
and
lift
completeharness
away
.
See
Fig
.
7
.

ENGINE
REMOVAL
AND
INSTALLATION

Fig
.
7
.



Remove
mainharnessfrom
top
engine
and
place
at
base
of

windshield
.

0012703

Fig
.
8
.



Mass
air
flow
sensor
connector
air
duct
hose
clamp,
and
air
cleaner
housing
mounting
bolts
(arrows)
.

9
.
Unbolt
andremove
complete
air
cleaner
housing
with



10
.
On
cars
with
automatic
transmission,
remove
front
and
mass
air
flow
sensor,
disconnecting
and
labeling
con-



rearbrackets
holding
transmission
cooler
linesto
side
nectors,
ducting
and
hoses
asnecessary
.
See
Fig
.
8
.



of
engine
.

NOTE
-

The
guide
tube
is
sealed
in
the
pan
with
an
O-ring
.
Check
that
theO-ring
comes
out
with
the
tube
.
Use
a
new
O-ring
when
installing
the
tube
.

Fig
.
2
.



Oil
dipstick
guide
tube
mounting
nut
(arrow)
on
M44
engine
.
Use
new
O-ring
at
base
of
tube
during
installatidn
.

6
.
Install
engine
lifting
equipment
at
front
engine
lifting
point
and
raise
engine
approximately
5
mm
(
1
/4
inch)
until
engineweight
is
supported
.

7
.
Workingbeneath
car,
separate
steering
column
shaft
from
steeringrack
at
universal
joint
.

"
Point
wheels
straight
ahead
before
disconnecting
shaft

from
rack
.
Mark
steering
column
shaft
joint
to
steering

rackspíndle
.
See
320
Steering
and
Wheel
Align-

ment
.

CAUTION
-

In
order
to
avoíd
the
need
for
front-end
realign-
ment,
do
notunbolt
power
steering
rack
from
sus-
pension
crossmember
.

8
.
Supportsuspension
crossmember
(subframe)
from
be-
low
usingappropriate
jacking
equipment
.

9
.
At
left
and
right
sides,
unbolt
control
arm
bushing
carri-
ers
from
body
.
Disconnect
stabilizer
bar
links
fromcon-

trol
arms
.
See
Fig
.
3
.

LUBRICATION
SYSTEM



119-
3

0011960
Fig
.
3
.



Stabilizer
bar
link
nut
(A)
and
control
arm
bushing
carrier
bolts
(B)
.
Right
side
shows
.

10
.
Remove
bolts
from
left
and
right
sides
of
suspension
crossmember
.
RemoveM10
nuts
from
bottom
of
left
and
right
engine
mounts
.
Lower
crossmember
as
far
as

possible
.
See
Fig
.
4
.

uu1ibb4

Fig
.
4
.



Suspension
crossmember
bolts
(A)
and
lower
engine
mount-
ing
nut
(B)
.
Right
side
shows
.

11
.
Remove
clamping
brackets
holding
fuel
lines
to
oil
pan
.

12
.
On
cars
with
automatic
transmission,
remove
ATF
cool-
er
line
brackets
from
oil
pan
.

13
.
Remove
engine
drive
belt
from
power
steering
pump
.

See020
Maintenance
Program
.

14
.
Unbolt
power
steering
pumpbracket
andremove

bracket
with
pump
.
Hang
pump
from
chassis
using
wire
.

OIL
PAN

8
.
Remove
air
plenum
from
rear
of
engine
compartment
.
See
640
Heating
and
Air
Conditioning
.

9
.
Release
drive
belt
tension
and
remove
alternator
drive
belt
.
Remove
A/C
compressor
drive
belt
.
See
Fig
.
6
.

B11143
Fig
.
6
.



To
remove
poly-ribbed
drive
belt,
pry
cover
from
front
of
ten-
sioner
.
Then
using
8
mm
hex
key,
turntensioner
clockwise
(arrow)
torelease
tension
and
slip
belt
off
pulleys
.

10
.
Unbolt
power
steering
reservoir
and
pull
reservoir
off
engine
mount
bracket
.

11
.
Without
disconnecting
fluid
lines,
remove
power
steer-
ing
bracket
(with
pump)
from
oil
panand
engine
block
.
See
Fig
.
7
.
Disconnect
fluid
lines
from
bracket
on
en-
gine
mount
.
Hang
pump
from
chassis
using
wire
.

12
.
Without
disconnecting
refrigerant
lines,
remove
A/C
compressor
from
engine
block
.
Hang
compressor
from
chassis
using
wire
.
See
640
Heating
and
Air
Condi-
tioning
.

13
.
Remove
oil
dipstick
guide
tube
mounting
bolt
and
re-
move
tube
.
See
Fig
.
8
.

NOTE-

The
guide
tube
is
sealed
in
the
oil
pan
with
an
O-ring
.
Check
that
the
O-ring
comes
out
with
the
tube
.
Use
anew
O-ring
when
installing
the
tube
.

14
.
On
cars
with
automatic
transmission,
remove
brackets
holding
ATF
cooler
linesto
oil
pan
and
cylinder
block
.

LUBRICATION
SYSTEM



119-
5

Fig
.
7
.



Power
steering
pump
mounting
bolts
(arrows)
.

Fig
.
8
.



Oil
dipstick
guide
tube
being
removed
.
Usea
new
O-ring
(arrow)
during
installation
.

15
.
Insta¡¡
engine
lifting
equipment
at
front
engine
lifting
point
and
raise
engine
just
until
its
weight
is
supported
.

16
.
Remove
nuts
at
bottom
of
left
and
right
engine
mounts
.
Remove
ground
wire
from
right
engine
mount
.
1-oosen
nuts
at
top
of
left
and
right
engine
mounts
(do
not
re-
move)
.

OIL
PAN

5
.
Remove
air
filter
housingcomplete
with
mass
air
flow
sensor
.
See113
Cylinder
HeadRemoval
and
Instal-
lation
.

6
.
Remove
oil
dipstick
guide
tube
mounting
bolt
.
Discon-
nect
oil
separator
hose
frombase
of
guide
tube
and
re-
move
tubefrom
oil
pan
(where
applicable)
.
See
Fig
.
10
.

NOTE-

The
guide
tube
is
sealed
in
the
blockusing
an
O-ring
.
Check
that
the
O-ring
comes
out
with
the
tube
.
Use
a
new
O-ring
when
installing
the
tube
.

Fig
.
10
.
Oil
dipstick
guide
tube
being
removed
.
Use
new
O-ring
(ar-
row)
during
installation
.

7
.
M50/S50US
engine
:
Using
a
clean
syringe,
remove
power
steering
fluid
from
fluid
reservoir
.
Disconnect
power
steering
fluid
lines
from
steering
rack
.
See
320
Steering
and
Wheel
Alignment
.

8
.
M52/S52US
engine
:
Unbolt
power
steering
reservoir
from
engíne,
then
tie
to
chassis
with
wire
.

9
.
Insta¡¡
engine
lifting
equipment
atfront
engine
lifting
point
and
raise
engine
approximately
5
mm
('/a
inch)
until
engineweight
is
supported
.
See
Fig
.
11
.

10
.
Workingbeneath
car,
separate
steering
column
shaft
from
steeringrack
at
universal
joint
.

"
Mark
steering
column
shaft
jointto
steering
rack
spin-

dle
.
Point
wheels
straight
ahead
before
disconnecting
shaft
from
rack
.
See
320
Steering
and
Wheel
Align-
ment
.

LUBRICATION
SYSTEM



119

Fig
.
11
.
Engine
lifting
equipment
shown
installed
acrossengíne
.

CA
UTION-

In
order
to
avoid
the
need
for
front-end
realign-
ment,
donot
unbolt
power
steering
rack
from
sus-
pension
crossmember
.

11
.
Support
suspension
crossmember
from
below
using
appropriate
jacking
equipment
.

12
.
Loosen
nuts
at
top
of
left
and
right
side
engine
mounts
.
Remove
nuts
from
bottom
of
left
and
right
side
engine
mounts
.

13
.
At
left
and
right
sides,
unbolt
control
arm
bushíng
carri-
ers
from
body
.
Disconnect
stabilizer
bar
links
fromcon-
trol
arms
.
Refer
to
Fig
.
3
.

14
.
Remove
bolts
from
left
and
right
sides
of
suspension
crossmember
and
lower
front
axle
as
far
as
possible
.

15
.
Remove
fuelline
clamping
brackets
from
oil
pan
.
On
cars
with
automatic
transmission,
remove
ATF
cooler
line
brackets
from
oil
pan
.

16
.
Remove
oil
pan
screws
.
Lower
and
remove
oil
pan
for-
ward
to
remove
.

CA
UTION-

If
the
oil
pan
does
not
separate
easily
from
the
en-
gine
cylinder
block,
a
few
taps
with
a
rubber
mallet
shouldbreak
it
free
.
Do
notpry
the
oil
pan
loose
.

OIL
PAN

CHARGING
SYSTEM

TROUBLESHOOTING
.............
.
.
.
.
.121-2

Charging
System
Quick-Check
...
.
..
.
...
.
121-2

Static
current
draw,
checking
........
.
...
.
121-2

BATTERY
SERVICE
....................
121-3

Battery
Testing
.
.
.
.
.
.........
.
........
.
121-3

Hydrometer
Testing
.
...
.
.
.
...
.
.........
121-3

Battery
Open-Circuit
Voltage
Test
....
.
....
121-4

Battery
Load
Voltage
Test
.
.
.
.
.
.
.........
121-4

Battery
Charging
.
.
.
.
...
.
.
.
.
.
.
.
.........
121-4

ALTERNATOR
SERVICE
.
.
.
.
.
.
.....
.
...
121-4

Chargingsystem,checking
.
.
.
.
.
.........
121-4

Alternator,
removingand
installing

(4-cylinder
engine)
....
.
.
.
.
.
.
.
.........
121-5

Alternator,
removingand
installing

(6-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.........
121-6

GENERAL

The
charging
system
consists
of
a
belt-driven
alternator

with
integral
voltage
regulator
and
a
battery
mounted
in
the

luggage
compartment
.

Various
versions
of
alternators,
voltage
regulators,
starters,

and
batteries
are
used
in
the
E36
cars
.
It
is
important
to
re-

place
components
according
tothe
original
equipment
speci-

fication
.
Check
with
an
authorized
BMW
dealer
for
specific

application
and
parts
information
.

WARNING
-

"
Weargoggles,
rubbergloves,
and
a
rubberapron
when
working
around
batteries
and
battery
acid
(electrolyte)
.

"
Battery
acid
contains
sulfuric
acid
and
can
cause
skin
irritation
and
burning
.
ff
acid
is
spilled
onyour
skin
or
clothing,
flush
the
area
at
once
with
large
quantities
of
water
.
lf
electrolyte
gets
into
your
eyes,flush
them
with
largequantities
of
clean
wa-
terfor
several
minutes
and
call
a
physician
.

"
Batteries
that
are
being
charged
or
are
fully
charged
give
off
explosive
hydrogen
gas
.
Keep
sparks
and
open
flames
away
.
Do
not
smoke
.

BATTERY,
STARTER,
ALTERNATOR



121-1

121
Battery,
Starter,
Alternator

GENERAL
..
.
...
.
........
.
...
.
.
.
.
.
.
.
.
.
121-1



Voltage
regulator,
removing
and
ínstalling
.
.
.
121-6

Alternator
brushes,
inspecting
and
replacing
.121-7

STARTER
SERVICE
....
.
.
.
.
.
..........
.121-7

Starter
Troubleshootíng



121-7



15
..
.
.
.
.
.
........
.
.
.

Starter,
removing
and
installing

(4-cylinder
engine)
....
.
.
.
............
.
121-8

Starter,
removing
and
installing

(6-cylinder
engine
with
manual
transmission)
..
.
...........
.
...
121-8

Starter,
removing
and
installing

(6-cylinder
engine
with

automatic
transmission)
................
121-9

Solenoid
switch,
removingand
installing
....
121-10

TABLES

a
.
Battery,
Starter
and
Charging
System

Troubleshooting
............
.
.
.
.
:...
........
121-2

b
.
Specific
Gravity
of
Battery
Electrolyte
at
80°F
(27°C)
...............
.
.
..
..........
121-3

c
.
Open-Circuit
Voltage
and
Battery
Charge
........
121-4

d
.
Battery
Load
Test-Minimum
Voltage
.
..........
121-4

CAUTION
-

"
Prior
to
disconnectiog
the
battery,
read
the
bat-tery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
viii
.
"
Disconnecting
the
battery
cables
may
erase
fault
codes
stored
in
control
unit
memory
.

"
Always
disconnect
the
negative
()
battery
cable
first
and
reconnect
it
last
.
Cover
the
battery
post
with
an
insulating
material
whenever
the
cable
is
removed
.

"
After
reconnecting
the
battery,
the
power
window
motors
must
be
reinitialized
.
See
511
Door
Win-
dows
.

"
Never
reverse
the
battery
cables
.
Even
a
momen-
tary
wrong
connection
can
damage
the
alternatoror
other
electrical
components
.

"
Battery
cables
may
be
the
same
color
.
Label
ca-blebefore
removing
.

GENERAL

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

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

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