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- When reinstalling seal carrier to crankcase:
Check locating sleeves for damage.
Replace gasitet between rear main seal carrier and
cranlt-
case.
Apply thin coat of
3 Bond 8 1209 or equivalent sealant to
oil pan
gasltet sealing surfaces.
* Lubricate crankshaft and seal contact surfaces.
4 Use BMW special tool 11 2 390 as an installation guide in fit-
ting seal over end of cranltshaft. Use care to push seal carrier
and support bushing on straight, without tilting. Remove in-
stallation guide carefully.
- Replace sealing washers under seal carrier mounting bolts.
- Install seal carrier mounting bolts and torque to specilica-
tions.
- lnstall oil pan bolts.
- Remainder of assembly is reverse of disassembly.
Install flywheel using new bolts,
Install clutch or torque converter and transmission.
* Fill engine with oil.
Run engine and
checlt for leaks.
Tightening torques Flywheel to crankshaft (use new bolts)
120 Nm (89 ft-lb)
011 dra~n plug to 011 pan (M12) 25 Nm (18 ft-lb)
Oil pan to
eng~ne block
M6 (8.8 grade) 10 Nm (89 in-lb)
M6 (1 0 9 grade) 12 Nm (9 ft-lb)
M8 (8.8 grade) 22 Nm (16 ft-lb)
Rear main seal carrier to crankcase
M6 10 Nrn (89 in-lb)
ME 22 Nm (16 ft-lb)

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.
[Lubrication System
< Disconnect electrical harness connector (arrow) at oil level
sensor.
< Remove lower oil pan mounting bolts (arrows)
CAUTIOI\C
If the lowerpan does not separate easily from upperpan, a
few taps with a rubber mallet should break it free. Do
notpry
the oil pan loose.
- When installing oil pan:
Thoroughly clean all old
gasltet material from mating sur-
faces and use a new gasket.
4 Install threaded guide studs at locations marked by arrows
to guide new oil pan
gasltet and oil pan into position and to
prevent damage to sealing lip.
- Install new oil pan mounting bolts (threads coated with
sealer).
Remove guide studs and install remainder of oil pan bolts.
- Remainder of reassembly is reverse of disassembly
- After adding engine oil, start and run engine. Raise engine
speed to 2,500 rpm until oil pressure warning light goes out
(about 5 seconds).
Tightening torques Lower oil pan to upper
oil pan
M6 (8.8 grade) 10 Nm (89 in-lb)
M6 (10.9 grade) 12 Nm (9 ft-lb)
M8 (8.8 grade) 22 Nm (16 ft-lb)
Oil drain plug to oil pan (M12) 25 Nm (18 ft-lb)

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11 9-26
/Lubrication System
< Use Allen wrench to adjust chain slaclc (B) by turning thread-
ed spacer
(A).
Oil pump chain adjustment
Slack
10 52 mrn (0.394i0.079 in)
- Coat remaining oil pump mounting fastener with Loctite 03. In-
stall and tighten.
- Remainder of assembly is reverse of disassembly.
- After adding engine oil, start and run engine. Raise engine
speed to
2,500 rpm until oil pressure warning light goes out
(about
5 seconds).
Tightening torques
Lower oil pan to upper oil pan
M6 (8.8 grade) 10
Nm (89 in-ib)
M6 (10.9 grade) 12
Nm (9 ft-lb)
M8 (8.8 grade) 22
Nrn (1 6 ft-lb)
Oil drain plug to oil pan (M12) 25 Nm (I8 ft-lb)
Oil pump cover to oil pump
(M6) 10 Nrn (89 in-lb)
Oilpump sprocket to shaft TKO) 45 Nm (33 it-lb)
Oil pump to engine bloclc
M8 (8.8 grade) 22 Nrn (16 ft-lb)
Oil pressure relief valve (&cylinder)
Remove oil
pump as described earlier. The oil pump pressure
relief valve is held in the side of the
oil pump with a circlip.
< Inspect oil pump relief valve components and bore for scor-
4. Sleeve
5. Circlip
- Install using a new circlip.
Oil
pressure relief valve assembly
,- ..., !~. -.-~. - ~- -~!~~-% h. .- .,, /to-cy~~noer engrnej ing or other damage.
1. Control plunger
2. Spring
3. Sealing O-ring

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120 lgnition System
...................... General
Special tools ...................
Warnings and cautions ...........
Engine management .............
................. lgnition system
Ignition system. troubleshooting
....
... Oscilloscope diagnostic diagrams
................ Misfire detection
............. Ignition System Service 120-9
.................... Ignition firing order 120-9
.............. Disabling ignition system 120-10
................... Checking for spark 120-1 0
lgnition coil assembly.
................. testing and replacing 120-1 0
.............. Crankshaftspeedsensor 120-12
............. Camshaft position sensors 120-1 4
...................... Knocksensors 120-16

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120-3
Ignition System
Warnings and cautions
The ignition system produces dangerous high voltage. In ad-
dition the sensitive electronic components can be damaged
if
proper precautions are not adhered to.
WARNING-
* Do not touch or disconnect any cables from the coils while
the engine is running or being
cranked by the starter.
The ignition system produces high voltages that can be
fatal. Avoid contact with exposed terminals. Use ex-
treme caution when working on a car with the ignition
switched on or the engine running.
- Connect and disconnect tlie DME system wiring and
test equipment leads only when the ignition is
OFF:
Before operating the starter without starting the engine
(for example when
making a compression test) always
disable the ignition.
CA
U TIOW-
Do not attempt to disable the ignition by removing the coils
from the spark plugs.
Connect or disconnect ignition system wires, multiple
wire connectors, and ignition test equipment leads only
while the ignition is
off Switch multimeter functions or
measurement ranges only with the test probes discon-
nected.
* Do not disconnect the battery while the engine is run-
ning.
A high impedance digital multimeter should be used for
all voltage and resistance tests. An LED test light
should be used in place of an incandescent-type test
lamp.
In general, make test connections only as specified by
BMW as described in this manual, or as described by
the instrument manufacturer.
Engine management
BMW €39 engines use an advanced engine management
system known as Digital Motor Electronics (DME). DME in-
corporates on-board diagnostics, fuel injection, ignition and
other engine control functions. DME variants are listed in
Table a. Engine management systems.
Second generation On-Board Diagnostics
(OED II) is incor-
porated into the engine management systems used on the
cars covered by this manual. Use a BMW-specific electronic
scan tool, or a "Generic"
OED II scan tool to access Diagnos-
tic Trouble Codes (DTCs). DTCs can help pinpoint ignition
ine management problems.

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Lnition switch
4 The positive (+) power supply to the ignition coils comes to
the ignition switch via an unloader relay. When the ignition
switch is turned on, the relay closes, to provide voltage to the
ignition coils. The coils are then actuated at the negative side
by the engine control module.
NOTE-
Schematic diagrams shown are for illustrative purposes only.
See ELE Electrical Wiring Diagrams for engine manage-
ment specific wiring information.
WARNING- Do not touch or disconnect any cables from the coils while
the engine is running or being cranked by the starter:
The ignition system produces high voltages that can be
fatal. Avoid contact with exposed terminals. Use ex-
treme caution when
working on a car with the ignition
switched on or the engine running.
* Connect and disconnect the DME system wiring and
test equipment leads only when the ignition is
OFF
Before operating the starter without starting the engine
(for example when
making a compression test), always
disable the ignition.
4 Knock sensors (arrows) monitor the combustion chamber for
engine-damaging knock. Six-cylinder models (shown) use
two sensors with each sensor monitoring three cylinders.
V-
8 models use four sensors, each monitoring two cylinders. If
engine
knock is detected, the ignition point is retarded by the
ECM.
I Ignition advance Ignition timing is electronically mapped and not adjustable.
The ECM uses engine load, engine speed, coolant tempera-
ture, knock detection, and intake air temperature as the basic
inputs for timing control.
A three dimensional map similar to
the one shown is digitally stored in the ECM.
- The initial ignition point is determined by the crankshaft
speed sensor during cranking. Once the engine is running.
timing is continually adjusted based on operating conditions.

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.-
ignition System
Disabling ignition system
The ignition system operates in a lethal voltage range and
should be disabled any time engine service or repair work is
being done that requires the ignition to be switched on.
The engine management system can be disabled by remov-
ing the DME main relay. The relay is located in the electronics
box (E-box) in the left rear of the engine
compartment, be.
neath the interior microfilter housing.
CAUTION- Relay locations may
vary. Use care when identifying relays.
See
610 Electrical Component Locations.
Checking for spark
CAUTION-
If
a spark test is done incorrecth damage to the Engine Con-
trol Module
(ECM) or the ignition coils may result.
NOTE-
Spark plug replacement is covered in 020 Maintenance.
Check~ng for spark is d~fflcult on englnes wlth d~str~butorless
ignition systems.
Try removing the spark plugs and inspecting for differences between them.
A poor-firing plug may be wet with fuel and/or ~. - ~
black and sooty, but not always. If a coil is not operating, the
engine management system will electrically disable the fuel
injector to that cylinder. The key is to look for differences be-
tween cylinders.
Ignition coil assembly, testing and
replacing
C4 UTION-
Use a digital multimeter for the following tests. I
- Remove plastic engine cover from top of valve cover by pry-
ing off bolt covers and removing cover mounting bolts.
- Raise car slowly while constantly checking position of jack
and car.
- Disconnect harness connector from coil. Connect multimeter
between terminal 15
(+) in connector and ground.
4 Terminal identification are typically molded into connector. In
photo, terminals are from left to right: 1,
4a, 15.

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120-1 2
ignition System
Crankshaftspeedsensor
Crankshaft speed sensor, replacing (M52, M52 TU and
M54 engines)
4 Crankshaft speed sensor for 6-cylinder engine is mounted in
the left rear side of the cylinder block below the starter (ar-
row). The sensor reads a toothed pulse wheel mounted to
the end of the crankshaft.
- if the Engine Control Module (ECM) does not receive a signal
from the crankshaft speed sensor during cranking, the en-
gine will not start.
- If the OBD II svstem misfire detection ~rotocol detects a cat- - - ~~
alysr oarnagin; faLlt oJe to a ma I-nclion in crandshafi speeo
sensor components. Ine Check Engine
lignr (Malfuncrion In-
dicator Light or MIL) will be illuminated.
NOTE-
If the crankshaft speed sensor pulse wheel is damaged, the
engine will have to be disassembled down to the crankshaft
to
reolace the wheel.
- Make certain ignition has been turned off.
- Raise car and support in a safe manner.
WARNING -
Make sure the car is stable and well supported at all times.
Use a professional automotive lift orjacltstands designed for
the ouroose.
A floor iaclc is not adequate support.
- Remove under engine splash guard
4 Working underneath starter:
Cut off wire tie securing crankshaft speed sensor harness
connector (arrow) to sensor.
* Disconnect harness connector.
4 Remove sensor mounting fastener (arrow) and remove sen-
sor from cylinder block.
- Installation is reverse of removal, noting the following:
Use a new O-ring when installing sensor.
Be sure wiring is routed in same orientation.
Secure sensor using new wire ties.
Use scan tool to read out and clear ECM fault memory.