1998 BMW 528i Fuel system

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Fuel Tank and Fuel Pump 1
Activated carbon canister I fuel tank leak
detection unit
(LDP or DMTL), removing . . -
and installing
- Raise rear end of car and support safely.
CAUTION-
Make sure the car is stable and well supported at all times.
Use a professional automotive lift
orjack stands designed for
the purpose.
A floor jack is not adequate support.
- Remove left rear wheel and inner fender panel
Remove carbon canisterlfuel tank leak detection unit
(V-8 model shown):
Disconnect electrical harness connector
(A) from fuel tank
leak detection unit.
Pinch and remove quick-disconnect fittings at intake line to
air filter housing
(5) and hose to expansion tank (C).
* Remove mounting clamp and lower canister with fuel tank
leak detection unit.
Installation is reverse of removal.
Tightening
torques
Hose clamp 8 - 13 mm dia. 2 Nrn (18 in-lb)
Hose clamp
13 - 16 rnm dia 3 Nm (27 in-lb)
Running losses (312-way) valve,
removing and installing
The running losses (312-way) valve is located under the car
beneath the driver's seat, just ahead of the fuel filter. A protec-
tive covershieldsfuel system components from road hazards
and dirt.
The engine control module
(ECM) controls the operation of
the 312-way valve (pulse-width modulated). On engine start
up, the valve solenoid is energized for 20 seconds in order to
supply full fuel volume to the fuel rail.
After20 seconds, the
solenoid is deactivated and sprung closed (the bypass is
opened). This reduces the amount of fuel circulating through
the fuel rail and diverts the excess to return to the fuel tank
through the fuel pressure regulator.
The fuel injectors are supplied with pressurized fuel, but ex-
cess fuel is diverted to the fuel tank without first passing
through the fuel rail. This prevents the excess fuel from ab-
sorbing heat in the engine compartment, thus lowering the
temperature and amount of vaporization in the fuel tank.

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160-25
Fuel Tank and Fuel pump1
The 312-way valve is also activated briefly if an engine misfire
is detected. This provides full fuel flow through the fuel rail to
determine if the misfire was caused by a lean fuel condition.
The valve is monitored by the ECM forfaults.
- Using BMW or compatible scan tool, read out fault memory.
See
OBD On-Board Diagnostics.
- Turn off ignition.
- Raise car and support safely.
CA UTIOW
Male sure the car is stable and well suppodedat all times.
Use a professional automotive lift
orjack stands designed for
the purpose.
A floor jack is not adequate support.
- Worlting under car beneath driver's seat, remove protective
panel from fuel filter and 312-way valve.
- Clamp off fuel lines at 312-way valve.
4 To remove 312-way valve (V-8 model shown):
Disconnect electrical harness connector
(A) from valve.
Remove vacuum hose
(B) from fuel pressure regulator.
* Remove hose clamps (arrows) and disconnect fuel lines.
Remove
M6 mounting nuts and lower 312-way valve.
WARNING-
Fuel will be spilled. Use shop rags to capture fuelas fuellines
are disconnected. Do not
smoke or work near heaters or oth-
er fire hazards.
- Installation is reverse of removal. Use new hose clamps
NOTE-
Install protective cover and seals correctly to keep moisture
and road dirt out of underbody fuel system components.
Tightening torques Hose clamps
8 - 13 mm dia.
2 Nm (18 in-lb)
Hose clamps
10 - 16 mm dia.
2 Nm (18 in-lb)
Hose clamps
18 mm dia. 3 Nm (27 in-lb)
Hose clamps 42
- 48 mm dia. 4 Nm 136 in-ib)

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.. - -
I Radiator and Cooling System
I I 4 The cooling cassette incorporates cooling coils for various
vehicle systems:
1. Steering fluid cooler
2. Transmission oil
coolel
3. AIC condenser
4 In V-8 cars produced after 911998 (M62 TU engine), the en-
gine radiator is divided into an upper chamber (about 80%)
and a lower chamber (about 20%). The ATF heat exchanger
is coupled to the lower chamber.
On cold engine start-up, the engine coolant is heated more
quicltly than the transmission fluid. Heat from engine coolant
is used to warm up the ATF faster, reducing drag in the trans-
mission and improving fuel mileage.
Once the ATF has reached normal operating temperature,
the ATF heat exchanger acts as cooling device. The lower
20% of the radiator
stays cooler than the upper chamber, so
the ATF is cooled more effectively.
4 M62 TU cooling system ducting at radiator:
1. Coolant distribution housing connection
2. Thermostat connection
3. Water cooled alternator connections
4. Transmission fluid heat exchanger connections

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-- -
Exhaust System
Oxygen sensors (precatalyst), replacing
(M52 TU and M54)
The precatalyst oxygen sensors are installed at the top of the
exhaust manifolds.
WARNING-
Allow components to cool before servicing.
- Using BMW scan tool DlSplus (Diagnostic Information Sys-
tem) or equivalent, read out and clear ECM fault codes.
Working at right side of engine above exhaust manifolds,
remove front or rear oxygen sensor harness connector
(arrows) from bracket, then separate plug.
NOTE-
In photo, secondary air pump has been removed for clarity.
Remove oxygen sensor using special oxygen sensor
removal socket.
Installation is reverse of removal
New sensor threads come coated with anti-seize paste.
If reusing a sensor, apply thin coat of anti-seize paste to
threads only. Do not contaminate tip of sensor with paste
or lubricants of any sort.
Install harness and connector in original location.
Tightening torque
- -.
Oxygen sensor to manifold 50 Nm (37 ft-lb)
Oxygen sensors (post-catalyst), replacing
(M52 TU and M54)
The post-catalyst oxygen sensors are installed at the rear of
the catalytic converters.
WARNING-
Allow components to cool before servicing
- Using BMW scan tool DlSplus or equivalent, read out and
clear ECM fault codes.
- Remove large cover from above fuel raillintake manifold.

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Suspension, Steering and Brakes - ~enerail
The main components of the system are the wheel speed
(pulse) sensors, the
ABSIASC or ABSIDSC control module,
and the hydraulic control unit.
Traction control also comes into operation during decelera-
tion. Decelerating on snowy or icy road surfaces can lead to
rear wheel slip. If a rear wheel starts to drag or lock up, the
ASC system can limit the problem by adjusting throttle, fuel
injection and ignition timing.
4 A switch (arrow) on the center console is used to toggle the
ASC on or off.
NOJE-
Even with the ASC system turned off, if the ASC control mod-
ule senses a difference in wheel speed (one wheel spinning)
the
ASC system applies modulated braling force to the slip-
ping wheel until traction is regained. There is no override of
fuelinjection function.
The ASC system is designed to be maintenance free. There
are no adjustments that can be made. Repair and trouble-
shooting of the ASC system requires special test equipment
and knowledge and should be performed only by an autho-
rized
BMW dealer.
ABSIASC traction
I 1.
control system
Wheel speed sensor
Wheel speed pulse wheel
Brake disk
Brake caliper
ABSIASC hydraulic unit
Brake master cylinder
Pedal operated throttle valve
ASC controlled throttle valve
Engine control module (ECM)
Accelerator pedal
ABSlASC control module

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300-1 4
I Susoension. Steerina and Brakes - General
DSC system I
Dynamic Stability Control (DSC)
Dynamic Stability Control (DSC) utilizes many principles and
components of the ASC traction control system. DSC is ac-
tive throughoutthe driving range, unlike ASC which is only ac-
tive during acceleration and braking. DSC helps stabilize the
vehicle in cornering and avoidance maneuvers by adjusting
engine controls such as throttle, ignition, fuel injection and the
application of
brake pressure individually to the wheels.
Inputs
fi- 0
2 4-* .. o
[11-' IJ
411m4
3?-
G
4 The DSC control module uses various inputs to determine
vehicle instability during braking, cornering, or reduced trac-
tion situations. Based upon these inputs the ABSIDSC con-
trol module sends outputs to the engine control module and
the ABSIDSC hydraulic unit to activate torque reduction pro-
tocols and braking intervention.
-
ABSIDSC control module
OUI~YIS
4
The DSC system can be toggled on and off by a switch
mounted on the center console. Turning off the DSC system
does not disable ABS or ASC functions.
+
Measure ride height (A) from center of fender arch to bottom
of wheel rim.
Car in normal loaded position on the ground. See Normal
loaded position.
Engine
control
module
Specified tires and wheels, correct tire pressure, even tire
wear
-'* 9-
.%A
Correct wheel bearing play
T'== ..t, 9 B
-.m
Model with air suspension (EHC): Disconnect electrical har-
ness connector to air supply pump to prevent automatic
height regulation.
When finished, reset ride height using BMW diagnostic
scan tools DIS or
MoDiC.
NOTE-
Airsupply pump is located beneath a cover under the spare
tire in the floor of the cargo compartment.
- If ride height is outside specification listed, install new
springs. Suspension spring removal and installation is cov-
ered in
310 Front Suspension and 330 Rear Suspension.
Normal loaded position
Each front seat 68 kg (150 Ib)
Center of rear seat 68 kg (150 lb)
Trunk 21 kg (46 lb)
Fuel tank full

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400-8
Body-General
Airbags
Front airbags, s~de a~rbags, pyrotechnic seat belt tensioners
and the Battery Safety Terminal (BST) are integrated into the
Supplemental Restraint System (SRS) and its variants.
NOTE-
The BMW SRS system is called Multiple Restra~nt System
(MRS). Over the years,
E39 cars were equipped with MRS,
MRS
11, MRS 111. Each version offers varied features and im-
provements over the previous system.
< As many as 8 airbags may be installed in E39 cars, depend-
ing on model and MRS version.
The front
airbags operate without sodium azide propellant,
widely considered an irritant when an
airbag is deployed.
Starting with
1999 models. "smart"front passenger and driver
airbags were installed. These are of the dual-threshold, dual
stage design, including a
sensorto help prevent the unneces-
sary deployment of the passenger side
airbag if the seat is un-
occupied.
MRS control Depend~ng on options chosen, one airbag may be installed in module each door of the sedan and Sport Wagon models, protecting
passengers against
s~de impacts.
Head Protection System (ITS)
airbags strelch diagonally
across the tops of the front doors.
Airbag deployment automatically triggers fuel shutoff, turns
on the hazard and interior lights, and unlocks the doors.
- -
WARNING -
Airbags are inflated by an explosive device. Handled im-
properly or without adequate safeguards,
airbag units can
be very dangerous. Special precautions must be observed
prior to any worlc at or near any of the airbags. See
721 Air-
bag System (SRS).
Always disconnect the battery and cover the negative
(-) battery terminal with an insulator before starting di-
agnostic, troubleshooting or service work on cars fitted
with SRS, and before doing any welding on the
car.

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51 5-2
/Central Locking and Anti-Theft
This section covers repair information for door, trunk and car-
go compartment locks, central locking, electronic
immob~liza-
tion (EWS) and anti-theft alarm (DWA).
€39 cars are equipped with sophisticated self-diagnostic elec-
trical systems. When experiencing malfunctions relating to
central locking. EWS or anti-theft systems, start the diagnosis
process using the
BMW service tester DIS, GT 1, MoDiC or
equivalent scan tool. An advanced diagnostic scan tool can
usually pinpoint electrical faults quickly and safely.
Additional electrical information can be found in:
610 Electrical Component Locations
ELE Electrical Wiring Diagrams
Central locking in E39 vehicles controls the door
locks, trunk
or tailgate lock and fuel filler flap lock. The control module for
the Central Body Electronics system (ZKE
Ill), lknown as the
General Module (GM
Ill), controls central locking.
ZKE
Ill manages the following central locking related func-
tions:
Central locking
* Keyless entry
Key memory
Power trunk release
Electric opening of tailgate
DWA alarm system
Diagnosis
General Module
4 The General Module (GM) (arrow) is responsible for the op-
eration of central body electronics. The GM is located behind
the glove compartment.
Based on input information, the GM uses internal transistors
to switch current flow (providing voltage or ground) through
circuits and actuators. Actuators are the final controlling de-
vices used by GM to operate or control various output func-
tions such as relays and motors.
The accompanying schematic, Central locking inputs and
outputs, illustrates the GM central locking system.