1999 BMW 525i tow

Downloaded from www.Manualslib.com manuals search engine
130-6
Fuel Injection
Fuel supply to the injection system is provided by a high pres-
sure electric pump mounted inside the fuel tank. The pump is
powered via the fuel pump relay. If the relay is faulty, the fuel
pump will not run and the engine will not start.
NOTE-
* Fuel delivery volume and fuel pressure are critical to prop-
er operation. Fuel pressure direcfly influences fuel deliv-
ery
Fuel pump relay, fuel pressure and fuel volume tests are
given in 160 Fuel Tank and Fuel Pump.
Relieving system fuel pressure
The fuel system retains fuel pressure in the system when the
engine is off. To prevent fuel from spraying on a hot engine,
system fuel pressure should be relieved beforedisconnecting
fuel lines. One method is to tightly wrap
ashop towel around a
fuel line fitting and loosen or disconnect the fitting. Cleanli-
ness is essential when working with fuel components. Thor-
oughly clean the unions before disconnecting fuel lines.
When system faults are detected, a diagnostic trouble code
(DTC) is stored in the engine control module (ECM). The MIL
also iiluminates if an emissions-related fault is detected
When faults arise, or if the malfunction indicator lamp (MIL) is
illuminated, begin troubleshooting by connecting BMW ser-
vice tester
DISplus. MoDiC, GTI or equivalent scan tool. The
capabilities of OBD
II software has the potential to save hours
of diagnostic time and to help avoid incorrect component re-
placement and possible damage to system components.
CAUTION-
- The tests in this section may set fault codes (DTCs) in the
ECM and illuminate the
MIL. Affer all testing is completed,
access and clear DJC fault memory using an
OED I1 or
BMW compatible scan tool. See OBD On-Board Diag-
nostics.
0 Only use a digital multimeter for electrical tests.
. Relay positions can vary Be sure to confirm relay posi-
tion by identifying the wiring in the socket using the wir-
ing diagrams found in ELE Electrical Wiring
Diagrams.

Downloaded from www.Manualslib.com manuals search engine
I Fuel Injection
Release injector locking clips at each injector and pry injector
wiring duct up off injectors.
Clamp off fuel supply line and fuel return line at end of fuel
rail. Disconnect fuel supply fuel return lines from fuel rail.
WARNING -
Clamp off the fuel lines and then wrap a clean shop towel
around the lines before removing them. Residual
fuelpres-
sure is present in the lines.
Fuel is discharged. Do not disconnect any wires that
could cause electrical
sparks. Do not smoke or work
near heaters or other fire hazards. Keep an approved
I fire extinguisher handy. I
- Remove fuel rail mounting fasteners
- Pull up on fuel rail and remove individual injectors by remov-
ing injector retaining clip and pulling injector from rail.
- Installation is reverse of removal. Fit new O-rings when in-
stalling injectors. For ease of installation, lightly lubricate in-
jector O-ring with
SAE9O gear lube.
Tightening torque Fuel rail to
intake manifold 10 Nm (89 in-lb)
Evaporative emissions, overview
On E39 MS 41 .I cars, the evaporative emissions system is
combined with the tank ventilation system. The evaporative
system is monitored by the ECM for correct purge operation
and leak detection.
The carbon (purge) canister is purged using engine vacuum
via the
purgevalve.The purgevalve (located nextto the mass
airflow sensor) is ECM controlled and regulates the purge
flow into the intake manifold. The valve is powered open and
closed by an internal spring.
If the evaporative emission valve circuit is faulty, a fault code
is set and the MIL is illuminated when OBD
II fault criteria are
exceeded. If the valve is mechanically faulty, poor driveability
may result and a mixture adaptation fault is stored in the
ECM.
The leak diagnosis pump (LDP) is activated by the ECM and
pressurizes the fuel tank and evaporative system as apart of
theOED I1 leakdetection monitor. If the LDP orthe LDP circuit
is defective, afault code is set and the MIL is illuminated when
OBD
I1 fault criteria are exceeded. The LDP is mounted the
left rear wheel well behind the fender liner.

Downloaded from www.Manualslib.com manuals search engine
Fuel Injection 1
NOTE-
The 1998 5281' with MS 41.1 requires a barometric pressure
sensor input signal for activation of the
LDP check. This sen-
sor is located on the passenger side strut tower
fo~lard of
ABS/ASC hydraulic unit.
Evaporative emissions
1. ECM
2. Purge valve
3. Leak detection pump (LDP) (in
lefl rear wheel housing)
4. Filter
5. Liquid vapor separator
6. Purge canister
7. Fuel tank
Secondary air injection, overview
The secondary air system pumps ambient air into the exhaust
stream afler a cold engine start to reduce the warm up time of
the catalytic converters and to reduces HC and CO emis-
sions. The ECM controls and monitors the secondary air in-
jection system. The secondary air pump operates at a start
temperature of between 10°C (50°F) and 40°C (104°F) and
continues to operate for a maximum of
2 minutes at idle
speed.
The electric air pump draws in ambient air and supplies it to
the divertervalve. The vacuum ventvalve (solenoid) switches
vacuum to open the divertervalve when activated by the
ECM. Once opened, the diverter valve allows air to be
pumped into the exhaust stream.

Downloaded from www.Manualslib.com manuals search engine
.-
I Fuel Tank and Fuel Pump
- Expose right side access cover:
Peel forward lip of carpet.
Release rubber grommet from center of access cover insu-
lation.
Peel back insulation at
perforations to expose fuel tank ac-
cess cover.
Remove right side cover to expose electrical harness con-
nector.
WARNING -
Fuel may be spilled. Do not smolce 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.
Remove
tank sending unit:
Release electrical harness by sliding lock back, then lifting
off connector.
a Disconnect hose (arrow).
Unscrew threaded collar from fuel
pumpifuel level sender.
NOTE-
BMW special spanner 16 1 020 should be used to remove
and install the threaded collar. Damage to the collar may re-
sult 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.
CAUTION-
Do not bend fuel level sender arm.
To remove fuel pump, press locking tabs (arrows) towards
pump body.
Lifl out pump, using care not to damage hoses.

Downloaded from www.Manualslib.com manuals search engine
/ ~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) -

Downloaded from www.Manualslib.com manuals search engine
Radiator and Cooling System
Cooling system, bleeding
Trapped air in the cooling system can prevent proper coolant
circulation and overheating. Wheneverthe coolant is drained
and filled, bleed the cooling system to remove trapped air.
4 Loosen bleed screw (arrow) on radiator expansion tank.
- Set temperature controls in passenger compartment to full
warm, set blower to low setting and turn ignition to
ON posi-
tion (do not start engine).
CAUTIOIG
On late model cars with latent heat pump, do not turn ignition
to ON position.
- Slowly add coolanUdistilled water mixture to expansion tank
until it spills from bleed screw. When coolant spilling from
bleed screws is free of air bubbles, tighten screw and replace
cap on expansion tank.
Run engine until it reaches operating temperature,
- After engine has cooled, recheck coolant level.
Top up so that coolant level indicator is at MAX.
- If trapped air cannot be bled manually, pressure-bleed sys-
tem using cooling system pressure tester.
CA UTlON--
Always use genuine BMW coolant or its equivalent to avoid
the formation of harmful, clogging deposits
in the cooling sys-
tem.
Tightening torque
Radiator bleed screw to radiator 2.5 Nm (22 in-lb)
Mechanical (viscous clutch) cooling fan,
removing and installing
The procedure given here describes the removal of the me-
chanical fan and fan shroud. It is possible to remove the fan
without the shroud.
< Working at top of fan shroud:
Remove expansion tank bleed screw (arrow) and expan-
sion tank locking tabs.
Push top of expansion
tank toward engine and lift to free
from lower mounts.
- Remove two expansion rivets in upper corners of fan shroud.
Unclip expansion tank bleed hose located under shroud.

Downloaded from www.Manualslib.com manuals search engine
--
Radiator and Cooling System 1
4 Lift fan and shroud together out of engine compartment.
- Detach upper and lower radiator hoses.
NOTE -
Later models use retaining clips to fasten coolant hoses to
expansion tank and radiator.
- Disconnect temperature sensor harness connector.
4 Remove radiator support bolts and supports (arrows). 6-cyl-
inder shown.
- Slide right side of radiator back toward engine and pull radi-
ator up to remove.
- Installation is reverse of removal, noting the following:
Fill radiator and cooling system. See Coolant, draining
and filling (6-cylinder models) or Coolant, draining
and filling (V-8 models).
Tightening torques
Engine block drain
plug to block 25 Nm (18 it-lb)
Radiator drain plug
to radiator 2 - 3 Nm (18 - 27 in-ib)
Expansion tank, removing and installing
- Raise front of car and support safely.
WARNING -
Make sure the car is stable and well supported at all times.
Use a professional automotive
/iff orjacltstands designed for
the purpose. A
floorjacl~ is not adequate support.
- Remove splash shield from under engine.
- Drain radiator as described earlier. See Coolant, draining
and filling (6-cylinder models) or Coolant, draining and
filling
(V-8 models).
I WARNING-
Allow cooling system to cool before opening or draining sys-
I tem.

Downloaded from www.Manualslib.com manuals search engine
170-25
Radiator and Cooling system]
< Disconnect expansion tank:
Remove expansion tank bleed screw and support clip
(A)
Loosen hose clamp (6) and disconnect coolant hose from
expansion tank.
Disconnect harness connector from coolant level sensor
(C).
Push top of expansion tank toward engine and disconnect
bleed hose.
Lift expansion
tank to free it from lower mounts, then lift
straight up to remove.
- Installation is reverse of removal, noting the following:
Fill radiator and cooling system as described earlier. See
Coolant, draining and filling (6-cylinder models) or
Coolant, draining and filling
(V-8 models).