2001 BMW 525i fuel control

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I Fuel Injection
Connector X60003 (continued) Electric throttle actuator
25
- 27 28
29
30
31
32
33
I I I
36 jlnput I Knoclc sensor 2, signal 1 Knock sensor
I I I
Input
26
Output
Output
input
Output
Input
I ' I . I
43 1 ln~ut I Electric throttle actuator, signal (Electric throttle actuator
Ground, electric throttle actuator
1 Not
used
Hot film mass air flow sensor
34
- 37
38
39
40
41
42
injection signal
Injection
signal
VANOS valve, signal
Not used
Thermostat characteristic map, signal
Crankshaft position sensor, signal
Not used
35 l~round I~nock sensor, shield 1 ~nock sensor
Cylinder
8 fuel injection valve
Cylinder
5 fuel injection valve
VANOS valve, cylinders
1-4
Characteristic map
Crankshaft positionlrpm sensor
input
input
Ground
Input
Output
Output
Innut
Hot film mass air flow sensor, signal
I
44
45 46
47
48
49
50
51
52
Connector )(GO004
Knock sensor 4, signal
Knock sensor, shield
Oil
level (thermal)
Injection, signal
Injection, signal
Electric throttle actuator, signal
Not used
Ground
Crankshaft position sensor, signal
Not used
Knoclc sensor, shield
Knock sensor
1, signal
Knock sensor
3, signal
Knock sensor, shield
Secondary air injection pump valve, signal
'
Ground
Input
Ground
input Input
Ground
Input
I' I ... I . ~
Knock sensor
Knocic sensor
Oil level sensor
Cylinder
4 fuel injection valve
Cylinder
1 fuel injection valve
Electric throttle actuator
Crankshaft sensor shield
Crankshaft
positionlrprn sensor
Knock sensor
Knock sensor
Knock sensor
Knock sensor
Secondary air injection pump valve
Notes
Instrument cluster
Integrated instrument cluster control
Secondary air injection pump
relay
Pin
1
2
3
Electric (auxiliary) cooling fan 4
Type
Output
Output
Outout
Descriptionlsignal type
Charge indicator signal (terminal
61)
Voltage signal, terminal 30h
Secondam air pump relay, activation
Input
5
Signal, electric (auxiliary) cooling fan, signal
I~ot used

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Fuel Injection I
Connector X60004 (continued)
8 10
11
12
13
14
15
16
9
Output 0
Input
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
39
llnput lsignal l~oolant outlet temperature sensor
Output
Output
Ground
Input
Output
I I - I
40 /output Istart signal Istarter relay
Pedal position sensor (PWG), signal
Output Input
Output
input
Input
Input
Input
Input
Input
input
Input
Output
Input/-output
Input/-output
37
Connector X60003
Pedal position sensor
Fuel pump relay, activation
Oil pressure indicator Pedal position sensor (PWG), ground
Pedal position sensor (PWG), signal
Pedal position sensor (PWG), power supply
Not used
Not used Fuel
pump relay
Instrument cluster
Pedal position sensor
Pedal position sensor
Pedal position sensor
Engine speed signal output (TD)
Not used
Signal
back-up light
DM-TL (diagnostic module,
tank leakage)
Signal oil level sensor
Right rear wheel speed, signal
Clutch pedal position switch, signal
Brake light switch, signal
Not used
Voltage supply, terminal
15
Data link, MFL (multi-function steering wheel)
Brake light test signal
AJC compressor signal
DM-TL (diagnostic module, tank
leakage)
Not used
Diagnosis signal
TxD
Communication link (EWS)
Not used
Not used
CAN-BUS hiqh
38 1 Ground l~round I Coolant outlet temperature sensor
OED II plug
Integrated instrument cluster control module (IKE)
Light module
ABSIDSC control module
Clutch pedal position switch
Brake light switch
Fuse
F14
Airbag contact coil spring
Brake light switch
Heating and
A/C control module
OBD
II plug
Electronic immobilizer (EWS)
CAN-Bus link
CAN-Bus link
Input/-output CAN-Bus low

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160 Fuel Tank and Fuel Pump
General ........................... .I6 0.2
Special tools ........................ .I6 0.2
Fuel pump ......................... .I6 0.3
Fuel tank evaporative control system ..... .I6 0.3
Evaporative system troubleshooting ..... .I6 0.4
Warnings and cautions ................ .I6 0.5
Fuel System Troubleshooting ...... .I6 0.6
Fuel pump fuse and relay .............. .I6 0.6
Operating fuel pump for tests ........... .I6 0.6
Fuel pump electrical circuit, testing ...... .I6 0.7
Fuel pump power consumption, testing ... .I6 0.9
Fuel pressure gauge, installing
(6-cylinder models)
................. .I6 0.1 0
Fuel pressure gauge, installing
(V-8 models) ....................... .I6 0.1 1
Fuel delivery, testing ................ .I6 0.12
Fuel Pump and Fuel Level Sender . . 160-15
Fuel level sender (right side) and
fuel pump. removing and installing
...... 160-15
Fuel level sender (left side).
removing and installing
............... 160-17
Siphon pump. removing and installing .... 160-1 9
Fuel Tank and Fuel Lines .......... 160-20
Fuel tank. draining ................... 160-20
Fuel tank. removing and installing ....... 160-21
Fuel expansion tank. removing
and installing
....................... 160-23
Activated carbon canister I fuel tank
leak detection unit
(LDP or DMTL).
removing and installing ............... 160-24
Running losses (312-way) valve.
removing and installing
............... 160-24

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Fuel Tank and Fuel Pump
Fuel pump
The electric fuel pump is mounted in the fuel tank in tandem
with the right side fuel level sender. The fuel pump delivers
pressurized fuel to the fuel injection system.
A pressure regu-
lator maintains system pressure. The quantity of fuel supplied
exceeds demand, so excess fuel returns to the fuel tank via a
return line. See
130 Fuel Injection for more information.
NOTE-
Fuel pump removal procedures are given under Fuel level
sender (right side) and fuel pump, removing and install-
ing.
Fuel tank evaporative control system
Evaporative control, also referred to as running losses con-
trol, is designed to prevent fuel system evaporative losses
from venting into the atmosphere.
The components of this system allow control and monitoring
of evaporative losses by the on-board diagnostic
(OED II)
software incorporated into the engine control module (ECM).
NOTE-
1997 V-8 models (540i) with Bosch DME M5.2 are not
equipped with an
OBD I1 running losses monitoring system.
Fuel tank evaporative
control system
(models with
DME MS42.0)
4 The main components of the evaporative control system and
their functions:
Fuel overflow
tank acts as a liquidlvapor separator
Carbon canister stores evaporated fuel.
Plumbing ducts vapors from fuel tank to canister and from
canister to intake
manifold.
- Carbon canister purge valve is controlled by enginecontrol
module (ECM).
Running losses or 312-way valve (not shown) shunts ex-
cess fuel volume directly
back to fuel tank before it circu-
lates through injector fuel rail (models with Siemens MS42
or Bosch M5.2.1 engine management only).
Leak detection unit (LDP or DMTL) pressurizes fuel
tank
and evaporative system to monitor system leaks (models
with Siemens MS42 or Bosch M5.2.1 and later).
Leak detection systems vary among models and years, and
are further described in
130 Fuel Injection.
NOTE -
"3/2-way valve", 'tunning losses valve" and "fuel changeover
valve" are used interchangeably
in BMW technical literature.

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Fuel Tank and Fuel Pump
Warnings and cautions
Observe the following warnings and cautions when servicing
the fuel system.
WARNING-
* The fuel system is designed to retain pressure even when
the ignition is off. When working with the fuelsystem, loos-
en the fuel lines slowly to allow residual
fuel pressure to
dissipate. Avoid spraying fuel. Use shop rags to capture
leaking fuel.
Before beginning any work on the fuel system, place a
fire extinguisher in the vicinity of the work area.
Fuel is highly flammable. When working around fuel, do
not disconnect any wires that could cause electrical
sparks. Do not smoke or worknearheaters or other fire
hazards.
* Always unscrew the fuel tank cap to release pressure
in the
tanlc before working on the tank or lines.
When disconnecting a fuel hose, wrap shop rag around
end of hose to prevent spray of fuel under pressure.
Do not use a work light with an incandescent bulb near
any fuel. Fuel may spray on the hot bulb causing a fire.
0 Make sure the worlc area is properly ventilated.
CAUTION-
- Prior to disconnecting the battery, read the battery discon-
nection cautions given in
001 General Cautions an4
Warnings.
Before
making any electrical tests with the ignition
turned on, disable the ignition system as described in
120 Ignition System. Be sure the battery is discon-
nected when replacing components.
To prevent damage to the ignition system or other DME
components, including the engine control module
(ECM), always connect and disconnect wires and test
equipment with the ignition off.
Cleanliness is essential when
worl~ing with the fuel sys-
tem. Thoroughly clean the fuel line unions before dis-
connecting any of the lines.
Use only clean tools. Keep removed parts clean and
sealed or covered with a clean, lint-free cloth, especial-
ly if completion of the repair is delayed.
Do not move the car while the fuel system is open.
Avoid using high pressure compressed air to blow out
lines and components. High pressure can rupture inter-
nal seals and gaskets.
Always replace seals, O-rings and hose clamps.

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.-- -
/ Fuel Tank and Fuel Pump - .. -. -- 1
Fuel pump fuse and relay
Troubleshooting of any fuel pump fault should begin with
checking the fuel pump fuse and the fuel pump relay. The
DME main relay should also be checked. The fuel pump relay
is located behind right side luggage compartment interior
panel.
I Fuel pump relay
BLU =blue ERN = blo$,m GRN =groan GRY = grsy ORG =orange PNI< =pink RED =red VIO =violel WHT = wlilte
rk-; I I 1 ECM
I I I 31 8 ,._--___.I
NOTE-
Special tools are required for some of the tests described
here.
4 Fuel pump circu~t is fuse-protected.
0 6-cylinder models with Siemens DME MS41 .I, MS42, V-8
models with Bosch DME M5.2, M5.2.1 englne manage-
ment: Fuse
F54,15A (luggage compartment fuse panel)
6-cylinder models with Siemens DME MS43 engine man-
agement: Fuse
F22,25A (glove compartment fuse panel)
V-8 models with Bosch DME M7.2: Fuse F54,25A (lug-
gage compartment fuse panel)
- Fuse 31 in glove compartment fuse panel supplies power to
coil side of fuel pump relay. Engine control module (ECM)
supplies switched ground to relay. During starting, fuel pump
runs as long as ignition switch is in START position and con-
tinues to run once engine starts. If electrical system fault in-
terrupts power to fuel pump, engine will not run.
. .
Operating fuel pump for tests
- To operate fuel pump for testing purposes without having to
run engine, bypass fuel pump relay to power pump directly.
< To run fuel pump, open luggage compartment and release
right side trim panel.

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--
I Fuel Tank and Fuel Pump
The plastic fuel tank is mounted underneath the center of the
car (underneath the rear seat). Mounted in the fuel tank are
the fuel pump and fuel level sending units. Connecting lines
for the evaporative emission control system and expansion
tank are also attached to the tank.
Fuel
tank capacity for E39 models
Tank capacity
70 liters (18.5 gal)
Reserve capacity
8 liters (2.1 gal)
Fuel tank, draining
Drain fuel tank into a safe storage unit using an approved fuel
pumping device.
WARNING-
# Before removing tank, be sure that all hot components,
such as the exhaust system, are completely cooled down.
Fuel may be spilled. Do not smoke or
work near heat-
ers or other fire hazards.
- Start engine and allow to run 10 - 15 seconds to fill fuel com-
pensating siphon assembly. This will allow both lobes of fuel
tank to he drawn off through fuel filler pipe,
- Disconnect negative cable from battery.
CAUTION-
Prior to disconnecting the batteg read the battery discon-
nection cautions given
in 001 General Warnings and Cau-
tions.
- Remove fuel tank filler cap
- Slide suction hose into filler neck about 130 cm (51 in.), twist-
ing as necessary. Withdraw fuel into storage unit.
- Monitor fuel level reduction in both lobes:
- Remove rear seat cushion and access both fuel tank send-
er harness connectors.
Use multimeter to measure resistance at both senders,
Resistance should drop as fuel level drops.
- If siphoning mechanism is faulty, drain left tank lobe sepa-
rately by removing sender cover and pumping fuel directly
out of left lobe.

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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.