engine BMW Z3 2002 Workshop Manual

155n
IndexDataTechnologyRepairsMaintenanceControlsOverview
BatteryRemoval and installation
Do not disconnect the battery
cables when the engine is running.
Disconnecting the battery cables when
the engine is running will cause a
voltage surge which will damage the
vehicle's onboard electronics.
Do not make any modifications in the
wires leading to the positive terminal. If
you do so, the battery safety terminal's
safety function will no longer be guaran-
teed. Repair and disposal must be
performed by trained technicians only.<
When removing the battery, disconnect
the negative terminal first, then the
positive terminal.
Unscrew the battery retaining clamp.
Z3 coupe:
Loosen the screw (arrow) on the battery
safety bar and remove the bar.
When installing the battery, connect the
positive terminal first, then connect the
negative terminal.
When installing the battery, be
sure that the battery and the
safety bar (Z3 coupe) are mounted
properly. If this is not done, the battery
will not be adequately secured in case
of an accident.< 367de336
Z3 cou
pe

156n
FusesIf an electrical accessory should fail,
switch it off and check the fuse.
The fuse box (electrical distribution
center), which contains spare fuses,
relays and plastic tweezers, is located
on the left-hand side of the engine
compartment, refer to page 120.
1. Press the retaining flap in and lift off
the cover
2. Use the plastic tweezers to remove
the fuse for the accessory or equip-
ment that has stopped working
3. If the fuse is burned through
("blown"), the metal strip will have
melted and separated. Replace the
blown fuse with a new fuse of the
same ampere rating (color code).365de080
A listing of the fuses, their respective
ampere ratings and the equipment in
their circuits is provided on the cover of
the fuse box.
When you close the fuse box, be sure
that the cover is seated securely.
Do not attempt to repair a burned
fuse or replace it with a fuse
having a different color or ampere
rating. To do this could cause a fire in
the vehicle resulting from a circuit over-
load.<
If a fuse burns through again, have the
source of the fault checked and
corrected by a BMW center.

158n
Jump-startingNever use spray starter fluids to start
the engine.
When your battery is discharged you can
used two jumper cables to start your
vehicle with power from the battery in a
second vehicle. You can also use the
same method to help start another
vehicle. Always use jumper cables with
fully insulated handles on the terminal
clamps.
Do not touch components
carrying high-voltage on a running
engine. Contact with components
carrying high voltage can cause fatal
injury. Carefully observe the following
instructions to avoid personal injury
and/or damage to one or both vehi-
cles.<
1. Ensure that the battery in the support
vehicle is also rated at 12 volts. This
information is provided on the top of
the battery casing
2. Do not disconnect the battery from
your vehicle's electrical system.
Switch off all electrical accessories in
both vehicles
3. Make absolutely certain that there is
no contact between the bodywork of
the two vehicles Ð short circuit
hazard
4. Start the engine on the support
vehicle and allow it to run
5. Use the jumper cable (+) to connect
the positive terminal of the battery in
the support vehicle with the auxiliary
positive terminal provided in the
engine compartment of your BMW
specifically for jump-starting. The
cover on this auxiliary terminal is
identified by a "+" symbol, refer to
the illustration. Pull up to open the
cover 367de381
6. Then connect the negative terminals.
Connect one end of the other jumper
cable (Ð) to either the support
vehicle's negative battery terminal or
a suitable ground on its engine or
bodywork. Connect the other end to
the negative battery terminal or a
suitable ground on the vehicle being
started. There is a special nut on the
strut dome of your BMW; refer to the
arrow in the illustration
Always adhere to this sequence
when connecting jumper cables;
failure to observe this procedure can
lead to sparks at the battery terminals
and pose an injury hazard.< 367de639

159n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Jump-starting Towing the vehicle7. Start the support vehicle's engine
and let it run at an increased idling
speed for a few minutes. Start the
engine on the vehicle needing the
jump-start, and allow it to run as
usual. If the first start attempt is not
successful, wait a few minutes
before another attempt in order to
allow the discharged battery to
recharge
8. Before disconnecting the jumper
cables let the engines run for a few
minutes
9. Then disconnect the jumper cables
in reverse sequence.
Depending on the cause of the fault,
have the battery recharged by your
BMW center.
Tow fittingThe screw-in tow fitting is stored in the
onboard tool kit; be sure that it remains
in the vehicle at all times. This fitting
is designed for installation in the tow
sockets located at the front and rear of
the vehicle, and is intended for towing
on paved road surfaces only.
It should not be used to pull a vehicle
out of deep snow, mud, sand, etc.
Comply with all applicable towing laws
and regulations at all times.Access to tow socketsFront:
Use a screwdriver to press the cover
out.367de375
Rear:
Use a screwdriver to press the cover
out.
Screw the tow fitting in until it is
tight against the stop. If you do
not, the threads can be damaged.
Do not tow the vehicle by any compo-
nents of the running gear, or lash them
down in any way. If you do so, the
components could be damaged,
leading to possible accidents.<
Use only a nylon towing strap to tow
the vehicle, since the inherent resil-
ience of this material helps protect both
vehicles from sudden jerking move-
ments.367de376

160n
Towing the vehicle
The towed vehicle should always
be the lighter of the two vehicles.
If this is not the case, it will not be
possible to control vehicle handling.<
Tow-startingIt is not possible to start the engine of a
vehicle with an automatic transmission
by towing or pushing the vehicle.
For instructions on jump-starting, refer
to page 158.
Never attempt to use your vehicle to
push another vehicle. This could result
in damage to the energy-absorbing
bumpers.
Towing a vehicle with automatic
transmission1. Place the selector lever in
position "N"
2. Towing speed:
max. 45 mph (70 km/h)
3. Towing distance:
max. 95 miles (150 km)
4. Leave the ignition key in position 1 to
ensure that brake lamps, turn signal
indicators, horn and windshield
wipers remain operative, and to
prevent the steering lock from
engaging
5. Switch on the hazard-warning
flashers (observe applicable legal
regulations).
Find some means of identifying the
vehicle in tow. Place a sign or warning
triangle in the rear window, for
instance.
Even when the electrical system
has failed, make sure that the igni-
tion key remains in position 1 to prevent
the steering lock from engaging.
The steering and brakes are without
power assist when the engine is off.
This means that increased effort is
required for steering and braking.<
Towing with a commercial tow
truck>Do not tow with sling-type equipment
>Use a wheel-lift or flatbed equipment
>Comply with applicable towing laws.
Never allow passengers to ride in
a towed vehicle for any reason.
Never attach tie-down hooks, chains,
straps, or tow hooks to tie rods, control
arms, or any other part of the vehicle
suspension, as severe damage to these
components will occur, leading to
possible accidents.< 367us124

164n
For vehicles with automatic transmis-
sion, Adaptive Transmission Control
(ATC) performs the optimum gear selec-
tion based on a number of factors. This
system reacts to your individual driving
style and the current driving conditions.
The ATC recognizes your individual
driving style from the positions and
movements of the accelerator pedal,
delays during braking, and the vehicle's
lateral acceleration when cornering.
ATC makes the appropriate selection
from different shift characteristics
which range from comfort-oriented to
performance-oriented.
367us358
In order to take driving conditions into
account, ATC registers corners and
both uphill and downhill gradients. For
example, if you maintain speed through
a curve, the transmission does not
upshift.
On uphill gradients, it shifts only when
the engine speed increases in order to
make more efficient use of power
reserves. On downhill gradients ATC
downshifts when the speed of the vehi-
cles increases causing the driver to
step on the brakes.
Deceleration sensors continuously
monitor the physical forces acting upon
the vehicle. In the event of a severe
frontal impact, the gas generators of
the driver and passenger-side front
airbags are ignited simultaneously.
However, the passenger-side airbag is
only triggered if an additional sensor
has recognized that the passenger seat
is occupied.
If it is necessary during a side impact, a
side airbag will be triggered on the side
where the collision occurs.
390de012
ATC
*
Airbags

165n
IndexDataTechnologyRepairsMaintenanceControlsOverview
The airbags located under the marked
covers inflate and unfold in a matter of
a few milliseconds. In this process they
tear through the designed breaking
points of the upholstered covers or
press them out.
Because the inflation process must be
virtually instantaneous, it is necessarily
accompanied by a certain amount of
ignition and inflation noise. The gas
required to inflate the airbags is not
dangerous, and it dissipates together
with the associated smoke.
The entire process is completed within
fractions of a second.Precision sensors monitor the number of
revolutions of the wheels. When
equipped with DSC, they also monitor
steering angle, lateral acceleration,
brake pressure and the movement of the
vehicle around its vertical axis.
If differences in the wheel speeds occur,
ASC+T recognizes the danger of wheel-
spin and reduces the drive torque. If
necessary, the system also responds
with additional applications of the brakes
at the rear wheels.
In addition, DSC permanently monitors
the vehicle's current operating condition
and compares it with an ideal condition
that is calculated from the sensor's
signals. If deviations from this occur
(understeering or oversteering, for
instance), DSC can stabilize the vehicle
in fractions of a second by adjusting
engine output and with the assistance of
braking intervention at individual wheels.
Within physically possible limits
dangerous skids can be prevented even
as they are just beginning.You may need some time to become
accustomed to this system's interven-
tion. However, it provides optimum
propulsive force and driving stability.
The braking intervention may be accom-
panied by a certain degree of noise.Airbags ASC+T/DSC
*

Overview
Controls and features
Operation, maintenance
Owner service procedures
Technical data
Index Advanced technology
169n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Engine specifications170
Dimensions171
Weights172
Capacities173
Electrical system174
Drive belts174
Data

170n
Z3 roadster 2.5i Z3 roadster 3.0i,
Z3 coupe 3.0i
Displacement
Number of cylinderscu. in (cm
m) 152.2 (2,494)
6181.8 (2,979)
6
Maximum power output
at engine speedhp
rpm184
6,000225
5,900
Maximum torqueat engine speedlb-ft (Nm)
rpm175 (237)
3,500214 (290)
3,500
Compression ratioe 10.5 10.2
Stroke
Borein (mm)
in (mm)2.95 (75.0)
3.31 (84.0)3.53 (89.6)
3.31 (84.0)
Fuel-injection system Digital electronic engine-management systemEngine specifications

173n
IndexDataTechnologyRepairsMaintenanceControlsOverview
Capacities
Notes
Fuel tank
reserve gal. (liters)
gal. (liters)approx. 13.5 (approx. 51)
approx. 2.1 (approx. 8.0)Fuel specification: page 26
Windshield washer system/
Headlamp washer system quarts (liters) approx. 5.3 (approx. 5.0)For details: page 122
Cooling system including heating circuit quarts (liters) 11.1 (10.5) For details: page 125
Engine with oil filter renewal quarts (liters) 6.9 (6.5) "BMW High Performance
Synthetic Oil"
For details: page 124
Manual transmission, automatic
transmission and differentialÐ Lifetime fluid, no fluid change
required