2000 BMW 540i Compression test

Downloaded from www.Manualslib.com manuals search engine
113-1
11 3 Cylinder Head
Removal and Installation
General ........................... .I 13-2
Special tools ........................ .I 13-2
Diagnostic Testing. ................ .I1 3-5
Cylinder compression, checking ......... ,113-5
Wet compression test ................. .I1 3-7
Cylinder leak-down test. ................ 11 3-8
Cylinder Head Removal and Installation
(M52 Engine) ...................... .I1 3-8
Cylinder head, removing, M52 engine .... ,113-8
Cylinder head, installing, M52 engine ... ,113-17
Cylinder Head Removal and Installation
(M52 TU and M54 Engines). ........ ,113-22
Cylinder head, removing, M52 TU
and
M54 engines. ................... .I1 3-22
Cylinder head, installing, M52 TU
and
M54 engine. .................... .I1 3-39
Double VANOS Timing
Chain Components
................ 11 3-46
Double VANOS timing chain components,
installing,
M52 TU and M54 engines ..... 113-46
Cylinder Head Removal and Installation
(M62 Engine). ..................... 11 3-56
Intake manifold, removal and installation,
M62 engine. ........................ 11 3-66
Left cylinder head, removing,
M62 engine. ........................ 11 3-61
Left cylinder head, installing,
M62 engine. ........................ 11 3-66
Right cylinder head, removing,
M62 engine ........................ 11 3-72
Right cylinder head, installing,
M62 engine ........................ 11 3-77

Downloaded from www.Manualslib.com manuals search engine
11 3-2
Cylinder Head Removal and Installation
This group covers cylinder head removal and installation as
well as cylinder
headlvalve diagnostic procedures.
In the procedures in this repair group, engines are referred to
by engine code. If necessary, see
100 Engine-General for
engine code and application information.
The information given in this repair group assumes that the
engine is installed in the engine bay. On the
6-cylinder en-
gines, the VANOS control unit must be removed in orderto re-
move the cylinder head from the engine block. On
M52TU
and M54 engines, camshafts must be removed from the cylin-
der head before the head is removed.
The cylinder head removal and installation procedures for the
M62 V-8 are also included, butthe proceduresforthe M62TU
V-8 with VANOS are not provided.
For cylinder head and valvetrain reconditioning information,
see
116 Cylinder Head and Valvetrain.
For specific repair procedures, refer to the appropriate repair
group:
020 Maintenance
116 Cylinder Head and Valvetrain
117 Camshaft Timing Chain
170 Radiator and Cooling System
610 Component locations
NOTE-
If a head gasket problem is suspected, a compression test or
leak-down test will usually detect the fault See Diagnostic
Testing later
in this group.
Special tools
Special BMW service tools are required to properly remove
and install the cylinder head on engines covered by this man-
ual. The special tools are used to time the valvetrain to the
crankshaft, and to remove the VANOS control unit, the cam-
shafts and the
Tom (El2) head bolts. Read the entire proce-
dure through before beginning the job.

Downloaded from www.Manualslib.com manuals search engine
113-5
Cylinder Head Removal and Installation I
< Fuel line plugs
(Tool No.
BMW 13 5 281113 5 282)
4 Fuel line removal tool for quick-disconnect fittings
(Tool No.
BMW 16 1 050)
< Tensioning bracket (V-8)
(Tool No. BMW 11 7 380)
Compressed air fitting for testing VANOS operation
((Tool No.
BMW 11 3 450)
< Upper timing cover installation tool set, V-8
(Tool No. BMW 11 1 41 0)
Cylinder compression, checking
A compression gauge is needed to make a compression test.
For accurate test, the battery and starter must be capable of
cranking the engine at least
300 rpm, and the engine should
be at normal operating temperature.
NOTE-
Performing a compression test may cause a fault to set in the
ECM and may illuminate the Malfunction
Indicator Light
(MIL). The light can only be turned out using either
BMW
special service scan tools or an equivalent aftermarket scan
tool. Disconnecting the battery will not erase the fault memo-
ry or turn out the light. See OBD On-Board Diagnostics.

Downloaded from www.Manualslib.com manuals search engine
. .- . --
Lr -- - - - -- Cylinder Head Removal and Installation I -
- Release pressure at compression gauge valve, then remove
gauge from spark plug hole. Repeat test for each cylinder
and compare results with values given in Table a.
Table a. Compression testing specifications
Minimum compression
6-cylinder
10-1 1 bar (142-156 psi)
V-8 12-14 bar (174-203 psi)
Maximum difference between
cylinders (all engines)
0.5 bar (7 psi)
- Compression readings may be interpreted as follows:
Low compression indicates a poorly sealed combustion
chamber.
0 Relatively even pressures that are below specification nor-
mally indicate worn piston rings
andlor cylinder walls.
Erratic values tend to indicate valve leakage.
Dramatic differences between cylinders are often a sign of
a failed head
gasket, burned valve, or broken piston ring.
- If readings are within specifications, reinstall spark plugs and
ignition coils.
NOTE-
Used spark plugs should be reinstalled in the same cylinder
from which they were removed.
Tightening torque Spark plug to cylinder head 25 Nm
(18 ft-lb)
lanition coils to cylinder head 10 Nm (7.5 ft-lb)
- Remainder of installation is reverse of removal. Be sure to re-
install all wires disconnected during test, especially ground
wires at coils and cylinder head cover (where applicable).
Wet compression test
To further help analyze the source of poorcompression,awet
compression test is the next step.
- Repeat compression test, this time squirt a teaspoon of oil
into each cylinder. The oil will temporarily help seal between
piston rings and cylinder wall, practically eliminating leakage
past rings for a short time.
- If this test yields a higher reading than "dry" compression
test, there is probably leakage between piston rings and
cylinder walls, due either to wear or to broken piston rings.
- Little or no change in compression reading indicates other
leakage, probably from valves.

Downloaded from www.Manualslib.com manuals search engine
113-8
[cylinder Head Removal and Installation 1
Cylinder leak-down test
The most conclusive diagnosis of low compression symp-
toms requires a cylinder leak-down test. Using a special
tester and compressed air, each cylinder, in turn, is pressur-
ized. The rate at which the air leaks out of the cylinder, as well
as where the air leaks out, can accurately pinpoint the magni-
tude and location of the leakage.
Before attempting any repair that requires major engine dis-
assembly, use a leak-down test to confirm low compression.
~YL~NDER HEAD REMOVAL AND
~NSTALLATION (M52 ENGINE)
WARNING-
Due to rislc of personal fnjur~: be sure the engine is cold be-
fore beginning the removal procedure.
Cylinder head removal and installation is a time consuming
repair procedure requiring multiple special
service tools.
Read the entire procedure before beginning the repair.
This procedure includes the following steps:
Cylinder head, removing,
M52 engine
Cylinder head, installing,
M52 engine
Cylinder head, removing, M52 engine
- Disconnect negative (-) cable from battery in luggage com-
partment.
CAUTION-
Prior to disconnecting the battea read the battery discon-
nection cautions in 001 General Cautions and Warnings.
-

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
Driveshaft
- Road test vehicle to check for noise or vibration
CAUTION-
Do not reuse self-locking nuts. These nuts are designed to
be used only once.
Avoid stressing the flex-disc when torquing the bolts.
Do this by counterholding the bolts and turning the nuts
on the flange side.
Tightening torques
Alunlinum driveshaft to flex-disc
- MI2 (use coated washers)
90 Nm (66 ft-lb)
Driveshaft
CV joint to final drive flange
Mi0 (Tom bolt)
70 Nm (51 ft-lb)
M8 (compression nut) 32 Nm (24 ft-lb)
Flex-disc to transmission flange or driveshaft
MI0 (8.8 grade) 48 Nm (35 ft-lb)
MI 0 (1 0.9 grade) 60 Nm (44 ft-lb)
- Mi2 (8.8 grade)
81 Nm (60 ft-lb)
- MI2 (10.9 grade) I00 Nm (74 ft-lb)
MI4 140 Nm (103 ft-lb)
Transmission
crossmember
to transmission (ME) 21 Nm (15 ft-lb)
. to chassis (M10) 42 Nm (30 ft-lb)
NOTE-
Boltgrade is marked on the bolt head. When replacing bolts,
only use bolts of the same strength and hardness as the orig-
inals installed.
Flex-disc, replacing
- Checlc flex-disc between front section of driveshafl and trans-
mission output flange for craclts, tears, missing pieces, or
distortion. Check for worn bolt hole bores in flange.
- If flex-disc needs replacement, remove driveshafl as de-
scribed earlier.
- Unbolt flex-disc from driveshaft.
NOTE-
Removal andinstallation of the bolts may be made easier by
placing a large hose clamp around the flex-disc, and tighten-
ing the clamp slightly to compress the rubber.