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err- .- Fuel Tank and Fuel Pump
FUELPUMP AND FUELLEVELSENDER
E39 models use a two-lobed fuel tank. Each lobe of the tank
has its own fuel level sending unit. Each sender has a float
connected to a variable resistance wipercontact. To equalize
fuel level between the two
tank lobes, a siphon pump is in-
stalled in the left lobe.
When replacing asender or fuel pump, always replace hose
clamps,
gasltets and O-rings.
WARNING
-
When removing the fuel level sender or the fuel pump, the
fuel tank should be drained to
1/4 capacity or below as de-
scribed later in this repair group.
NOTE-
The compensating siphon pump maintains the fuel level be-
tween the right and left tank lobes. If fuel level sender resis-
tances are not approximately the same on left and right,
remove the senders and visually inspect the level in each
lobe. If the levels are different, check the siphon pump.
Fuel level sender resistances
Float position
l~est results (Q
Down (empty) 150- 70
Up (full) 1401 -415
Fuel level sender (right side) and fuel
pump, removing
and installing
- Drain fuel from tank as described later.
- Disconnect negative cable from battery.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- To access top of fuel tank, remove rear seat lower cushion by
lifting front edge
off catches.
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.- .
Fuel Tank and Fuel Pump
- To reinstall:
Use new sealing ring at tank collar.
* Align tab of sending unit with matching recess in opening
of tank.
Be sure that fuel line connections point in same direction
as they came out.
Reconnect harness connector and hose.
Fill tank and check for leaks by running engine.
Install access cover and its mounting fasteners.
CAUTIOI\C
After finishing repairs but before starting engine, be sure
there is at least
5 liters (1.5 gallons) of fuel in the tank. The
NOTE-
It is common practice to replace the fuel filter when the fuel
pump
unit is replaced. See 020 Maintenance.
Tightening torque
Tank collar locking ring to tank 35 Nm (26 lb-ft)
Fuel level sender (left side),
removing and installing
The procedure for removing and replacing the left side fuel
level sender is
simllar to that used for the r~ght side. There is
no fuel pump on the left side.
- Remove rear seat lower cushion by lifting off catches at front.
- Expose left side access cover:
- Peel forward lip of carpet.
Release rubber grommet from center of access cover
insulation.
Peel back insulation at
perforations to expose fuel tank
access cover.
Remove cover to expose electrical harness connector.
WARNING-
Fuel may be spilled. Do not smoke or work near heaters or
other fire hazards.
When disconnecting fuel hose, wrap shop rag around
end of hose to prevent spray of fuel under pressure.
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/ ~uel Tank and Fuel Pump
4 Remove tank sending unit:
Disconnect electrical harness connector.
Disconnect hose (arrow).
- Unscrew threaded collar from fuel level sender.
NOTE-
BMW special spanner 16 1 020 should be used to remove
and install the threaded collar. Damage to the collar may
result if the special tool is not used.
Slowly withdraw assembly from tank, allowing fuel to drain
off. If necessary, push level sender arm toward sending
unit to facilitate removal.
CA UTIOW-
Do not bend fuel level sender arm.
4 Once level sensor unit has been lifted partially out of tank,
disconnect tank siphon hose by pressing tabs (arrows).
- Installation is reverse of removal
Attach tank siphon hose to sender unit firmly.
Use new sealing ring at tank collar.
. Be sure that fuel sender float points in same direction as
during removal.
- Reconnect harness connector.
Fill tank and
check for leaks by running engine.
CAUTION-
After finishing repairs but before starting engine, be sure
there is at least
5 liters (1.5gallons) of fuel in tan/(. The fuel
pump will be damaged if run without fuel.
Tightening
torque
Tank collar loclting rlng to tanlt 35 Nm (26 lb-ft) -
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7 .- A Fuel Tank and Fuel Pump
Siphon pump, removing and installing
The fuel compensating siphon pump equalizes fuel level
between the two fuel tank lobes.
- Drain fuel tank as described later,
WARNING -
Fuel may be spilled. Do not smoke or work near heaters or
other fire hazards.
- Remove left and right fuel level sensors and fuel pump as
described earlier.
4 Once left side level sensor unit has been lifted partially out
of tank, disconnect tank siphon hose by pressing tabs
(arrows).
- The tank lobe siphon pump is held to baffle in bottom of right
tank lobe. Release retainer and lift out pump.
- Installation is reverse of removal.
Attach siphon pump to right side baffle.
Attach tank siphon hose to left sender unit firmly.
Use new sealing ring at tank collars
Be sure that fuel sender floats point in same direction as
during removal.
Reconnect harness connectors.
. Before starting engine, fill fuel tank with at least 5 liters
(1.5 gallons) of fuel.
Check for
leaks by running engine.
Afler finishing repairs but before starting engine, be sure
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Fuel Tank and Fuel pump/
- Remove suction hose from tank filler neck carefully to avoid
damaging filler neck baffle plate.
CAUTION-
After finishing repairs but before starling engine, be sure
there is at least
5 liters (1.5 gallons) of fuel in tanlc. The fuel
pump will be damaged if run without fuel.
Fuel tank, removing and installing
- Remove fuel tank filler cap and drain tank as described
earlier.
- Disconnect negative cable from battery.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- Remove rear seat bottom cushion. Peel forward lip of carpet
from beneath seat cushion and carefully peel back insulation
to expose fuel tank access cover on left and right sides. Re-
move covers.
Disconnect right side supply hose and
electr~cal harness
connector (arrows).
D~sconnect left side return hose and electrical harness
connector.
Working inside car, disconnect parking
bralte cable ends
from parking brake lever. See
340 Brakes.
Lift car and support safely.
Make sure the car is stable and
we/ supported at all times.
Use a professional automotive lift
orjack stands designed for
the purpose. A floorjaclc is not adequate support.
- Remove complete exhaust system and heat shield. See 180
Exhaust System.
- Remove drive shaft. See 260 Driveshaft
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160-22
Fuel Tank and Fuel Pump
4 Working underneath car, pinch off supply and return fuel hos-
es (arrows), then disconnect hoses from rigid metal lines.
- Remove right rear wheel and wheel housing splash shield.
4 Worlting at right rear wheel housing, loosen hose clamp
(arrow) and disconnect filler pipe from tank.
- Support tank from below. Remove tank strap mounting bolts.
Lower and remove tank, disconnecting right side vent and
other
hoses/electrical connectors as necessary.
Always use new seals, gaskets, O-rings, and hose clamps.
lnspect hoses and replace any that are chafed,
dr~ed out or
cracked.
lnspect heat shield and replace if corroded.
Inspect rubber buffers and
hers on fuel tank, support
straps and on underside of body. Replace rubber parts that
are hardened or damaged.
- After finishing repairs but before starting engine, fill fuel tank
with at least
5 liters (1.5 gallons) of fuel.
CAUTlOI+
The fuelpump will be damaged if run without fuel.
* If the filler neck has been removed from the body, be
sure to reattach the
neck grounding screw (where ap-
plicable). Check electrical resistance between the
ground tab and wheel
hub. The resistance should be
no
hiaher than 0.6f2
Tightening torques
Fuel tank to body 23 Nm (17 ft-lb)
Hose clamp
8 -13 mm dia. 2 Nm (18 in-lb)
Hose clamp 13
- 16 mm dia. 3 Nm (27 in-lb)
Hose clamp 42
- 48 mm dia. 4 Nm (36 in-lb)
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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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I Radiator and Cooling System
This section covers component repair information for the en-
gine cooling system.
Heater core replacement is covered in
640 Heating and Air
Conditioning.
Special tools
Special tools are necessaryfor belt-driven fan clutch removal
and also for pressure testing the cooling system.
4 Cooling fan counterhold wrench
(Tool No. BMW
11 5 030)
4 Cooling fan wrench
(Tool No. BMW
11 5 040)
< Expansion tank cap test adaptor
(Tool No.
BMW 17 0 007)
17 0 002 4 Cooling system pressure tester set
1 17 o 005 (Tool No. BMW 17 0 OOZi17 0 005)