2001 BMW 525i Front

Downloaded from www.Manualslib.com manuals search engine
Lubrication System
- Lower front suspension and remove oil pan, as described
earlier, to gain access to oil pump.
Remove oil pump
sprocket mounting nut (left-hand thread)
(arrow). Lift sprocket off together with drive chain.
Engines produced to 9/98: Remove oil pump with pick-up
tube. Pick-up tube is bolted to side of oil pump.
Engines produced from 9/98 to 01/00: Remove pick-up
tube, scraper tray and oil pump as a unit.
Engines produced from 01/00: Remove oil pump pick-up
tube bolts and remove pick-up tube before removing pump.
Remove mounting bolts from oil pump. Withdraw pump.
NOTE-
Record location of any spacers between pump and engine
bloclc Note positions of locating dowels.
- Remove cover from oil pump and check for wear or scoring.
Spin oil pump shaft and
check that gears turn smoothly. Re-
place pump if gears spin with difficulty
orany wear is present.
- Inspect oil pressure relief valve as described later.
- Installation is reverse of removal, noting the following:
Replace pick-up tube O-ring (if applicable).
- Align sprocket splines to oil pump shaft spl~nes before
tightening sprocket nut.
- 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 Oil drain plug to oil pan 25
Nm (18 ft-lb)
Oil pan to engine
bloclc
M6 (8.8 grade)
M6 (10.9 grade)
M8 (8.8 grade)
10 Nm (89 in-lb)
12
Nrn (9 ft-lb)
22 Nm (16 ft-lb)
Oil pump sprocket to oil pump shait
(M10 x 1) (left hand thread)
25 Nm (1 8 it-lb)
Oil pump to crankcase (ME) 22 Nm (1 6 it-lb)
Oil pump pickup tube to cranltcase (M6) 10 Nm (89 in-lb)

Downloaded from www.Manualslib.com manuals search engine
< Ignition voltage peaks in response to sudden acceleration
load:
1. Normal ignition pattern. Beginning of dying out pattern
is not much higher than ignition voltage peak.
2. Beginning of dying out pattern considerably higher than
ignition voltage peak. Fault in injection system:
Lean fuel mixture
Defective fuel injector
Low compression in cylinder
-, :I 1- i : !I I 1 iFh-ti ,... > .... 1 ...,,,,. J ,,,.! ,.,. { .,., i .,,, 8 ,.,.$,.,! ,:,, ., xt * ", *, ,, >* m2>2n,,,,
Ignition firing order
Normal secondary voltage patterns
(4-cylinder pattern shown).
4 Each ignition coil is mounted above the corresponding spark
plug.
- Number one cylinder is located at the front on 6-cylinder
models.
Number one cylinder is located at the right (passenger side)
front on
V-8 models. Cylinder firing order is shown.
Firing order
M52 - M52 TU - M54 6-cylinder 1-5-3-6-2-4
M62 - M62 TU V-8 1-5-4-8-6-3-7-2

Downloaded from www.Manualslib.com manuals search engine
I Ignition System
Camshaft position sensors
The camshaft position sensors are used by the englne man-
agement system for VANOS control, sequential fuel injection
and knock control.
Intake camshaft position sensor, replacing
(M52,M52 TU
and M54 engines)
- Make certain ignition has been turned off.
- Remove plastic cover from above fuel injectors by prying off
bolt covers and removing cover mounting bolts.
Remove complete air filter housing:
Disconnect electrical harness connector on mass air flow
sensor
(A).
Detach vacuum line at intake boot (B).
Loosen hose clamp at intake boot and detach air duct con-
nections
(C).
* Disconnect cold air duct tube (D).
Remove filter housing mounting screws (E).
- Disconnect harness connector from VANOS solenoid and
unscrew solenoid from VANOS control unit. Be prepared with
shop rags to catch oil released from VANOS unit.
Remove camshaft sensor (arrow) from
left front of cyl~nder
head, next to top of oil filter housing.
Disconnect camshaft sensor harness from under intake
manifold. Prior to removal, attach a stiff piece of wire to the
harness connector end to preserve proper routing of harness
for reinstallation.
Installation is reverse of removal, noting the following:
Use new O-rings when installing sensor and solenoid.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear
ECM fault memory
Tightening torques
-
Intake camshaft sensor to cylinder head 10 Nrn (7 ft-lb)
VANOS solenoid to VANOS control unit 30 Nm (22 ft-lb)

Downloaded from www.Manualslib.com manuals search engine
120-15
Ignition system1
Exhaust camshaft position sensor, replacing
(M52 TU and M54 engines)
- Make sure ignition has been turned off.
4 Working at front of engine on exhaust (right) side, detach ex-
haust camshaft position sensor electrical harness connector
(arrow) and remove sensor.
- Installation is reverse of removal, noting the following:
Use a new O-ring when installing sensor.
- Use scan tool to read out and clear ECM fault memory.
Tightening torque
Exhaust camshaft sensor
to cylinder head 10 Nm (7 ft-lb)
Intake camshaft position sensor, replacing
(M62 and M62 TU engines)
- Make sure ignition has been turned off
4 Remove top engine cover by releasing quick release fasten-
ers (arrows) by pressing down.
4 Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor and
intalte air tempera-
ture sensor electrical harnesses
(A and B).
Remove air filter housing mounting fastener (arrow).
Loosen hose clamps
(C and D).
Remove hose at idle air stabilizer.
Remove air filter housing with mass air flow sensor.
- Remove intalte hose from throttle body.

Downloaded from www.Manualslib.com manuals search engine
120-1 6
Ignition System
Remove camshaft sensor (arrow) from front of right cylinder
head.
Disconnect camshaft sensor harness from cable duct above
right cylinder head.
Installation is reverse of removal, noting the following:
Use new O-ring when installing sensor.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear ECM fault memory.
Tightening torque Intake camshaft sensor to timing chain 5 Nm
(3.5 ft-lb)
cover
Knock sensors
Knock sensors, replacing (M52, M52 TU and M54
engines)
The knock sensors are bolted to the left side of the cylinder
block under the intake manifold.
- Remove intalte manifold as described in 113 Cylinder Head
Removal and Installation.
D~sconnect knock sensor electrical harness connector (A) on
left side of engine cylinder block.
Remove knock sensor
mount~ng bolts (arrows) on side of
cyllnder block. Remove sensors.
Note the installed angle of the
lnocl~ sensor on the bloc/( be-
fore removing it. Reinstall the sensor
in the same position. Be
sure to use a torque wrench when tightening the sensor
mounting bolt.
< Clean lknock sensor contact surface on engine bloclc and
sensor (arrows) before installing
ltnock sensor.
Tightening torque
Knock sensor to head 20 Nm (15 ft-lb)
- Use scan tool to read out and clear ECM fault memory.
Knock sensors, replacing
(M62 and M62 TU engines)
The
knock sensors are bolted to the side of the cylinder block
under the
intake manifold.

Downloaded from www.Manualslib.com manuals search engine
121-18
I Battery, Starter, Alternator
Alternator, removing and installing
(M62 TU engine, water cooled)
V-8 models produced after 9/98 are equipped with a water
cooled alternator.
CAUTION-
Allow engine to cool before removing alternator as coolant
will
escape from the alternator water jacket.
- Disconnect negative (-) battery cable
CAUTION- Prior to disconnecting the
battew read the battery discon-
nection cautions given in
001 General Warnings and Cau-
tions.
- Remove radiator cooling fan and fan shroud. See 170 Radi-
ator and Cooling System.
- Drain engine cooling system. See 170 Radiator and Cool-
ing System.
- Remove alternator drive belt. See 020 Maintenance.
- Disconnect battery lead (terminal 30 or B+) and two-pin har-
ness connector from front of alternator.
I < Remove bolts securing alternator to water jacket and remove
aling ring
alternator.
NOTE- If necessary, raise car and remove engine compartment
splash shield to access lower alternator mounting bolts.
The upper coolant hose can also
be removed to assist al-
ternator removal.

Downloaded from www.Manualslib.com manuals search engine
Fuel Injection
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
Remove engine coolant temperature sensor:
Unclip crankcase vent hose
(C) from cylinder head cover.
Remove plastic cover
(6) from atop intake manifold run-
ners.
Working under front of intake manifold, disconnect ECT
harness.
Unscrew ECT sensor
(C) from cylinder head.
Installation is reverse of removal:
Use new copper sealing washers when installing sensor.
Replace any engine coolant lost.
Tightening torque
Temperature sensor to cylinder head
13 Nm (10 it-lb)
Intake air temperature ([AT) sensor,
testing and replacing
4 The intake air temperature (IAT) sensor (arrow) signal is
used by the ECM to monitor intake air temperature for fuel
and
igntion adaptation. The sensor is .ocared in rne 'ntane
man:lold behind the throttle housng.
The ECM monitors an applied voltage (5 vdc) to the sensor
The voltage drop across the sensor varies as the intake air
temperature (sensor resistance) changes.
NOJE-
The IATsensor is an NTC (negative temperature coefficient)
type sensor. In other words, as the temperature rises, resis-
tance through the sensor decreases.
If the IAT sensor input is implausible, a
fault code is set.The
MIL is illuminated when OED II fault criteria are exceeded.
The ECM then operates the engine using only the engine
coolant temperature (ECT) sensor input.
The intake air temperature sensor can be tested using a
mul-
timeter across its terminals:
/ IAT sensor resistance @ 20" C (68°F) / 2.2 - 2.7 lkCk
~ -- ~~ -
CAUTION--
Be sure ignition is
OFFbefore disconnecting or reconnecting
DME system components.

Downloaded from www.Manualslib.com manuals search engine
130-1 8
1 Fuel injection Secondary air injection
1. Secondary air pump (in right
front wheel housing)
2. Secondary air vacuum vent
valve solenoid (on intake mani-
fold)
3. Secondary air check valve
4. Intake manifold
5. Exhaust manifolds
6. Diverter valve (at exhaust mani-
fold)
Engine control module (ECM),
removing and installing
The ECM uses stored functions and processing programs to
process the input signals from the sensors. These input sig-
nals are used to calculate the control (output) signals to the
actuators
(e.g., ignition coils, injectors).
NOTE-
Consult an authorized BMW dealer before replacing the
ECM.
- Disconnect negative (-) battery cable. Wait approximately
one minute.
Prior to disconnecting the
battely, read the battery discon-
nection cautions in
001 General Warnings and Cautions.
Access engine control module (ECM):
Release interior ventilation filter cover latch
(A) and re-
move cover.
Release plastic locking tab
(B).
Rotate air duct inward (arrow) to unloclc from bulk head
and remove duct.
Release spring lock
(C) to remove lower filter housing.
Slide filter housing away from inner fender to remove.
- Remove electrical box (E-box) cover fasteners and remove
cover.
- If testing ECM or connected components, use breakout box
to allow tests to be made with connector attached to the
ECM. This prevents damage to small terminals in connector.