1998 BMW 528i Fuel system

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120-6
lgnition System
lgnition system, troubleshooting
Troubleshooting ignition system faults should begin with an
interrogation of the On-Board Diagnostics (OBD
II) system.
The OBD
II system detects ignition system misfire and other
related faults. When faults are detected, the OBD
II system
stores a Diagnostic Trouble Code (DTC) in the Engine Con-
trol Module (ECM) along with other pertinent fault information.
4 In addition, the Malfunction Indicator Light (MIL) will come on
if an emissions related fault is detected. Additional OBD
II in-
formation, including a DTC lookup table, can be found in
OED On-Board Diagnostics.
NOTE-
BMWmodels covered in this manual were equipped with one
of three versions of
MIL warning lights (as shown).
Misfire detection
Engine m~sfire in one or more cylinders, may be caused by a
var~ety of malfunctions in various subsystems. The OBD II
system ~ncorporated into the engine management systems is
des~gned to detect and warn of misfire faults during englne
operat~on. See OED On Board Diagnostics.
WARNING -
lgnition misfires can cause high hydrocarbon exhaust emis-
sions andcatalytic converter damage. For this reason, if a se-
vere misfire is detected, the fuel injector
will be turned off to
the specific cylinder and the
MIL will be illuminated. A misfire
may also produce an overheated catalytic converter, which
can be a fire hazard.
Oscilloscope diagnostic diagrams
One way to diagnose a faulty coil is to use an oscilloscope to
analyze spark quality with the engine running.
See Table b. lgnition secondary voltage diagnostics for
list of common ignition
coil voltage faults and related causes.

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120-7
Ignition System
Spark plug electrode gap /Too small /TOO big
Table
b. Ignition secondary voltage diagnostics
Secondary
voltage low
Fuel air mixture
I I Too lean
Secondary
voltage high
Spark plug electrode
Worniburnt
4 The illustration shows normal scope trace of spark at idle.
1. Start of ignition voltage peak
2 Level of ignition voltage
3. Level of combustion voltage
4. Period of combustion
5. Combustion curve characteristics
6. Start of decay process
7. Termination oscillations
Spark plug electrode
temperature
Engine compression
Spark plug wires
4 Short combustion period (indicates large spark plug gap).
Too
high
Too
low
I"" 9, 10 I" to I!, r) i" 21 10 il bW,rn?7G
Too low
Too high
Faulty
4 Ignition spark at idle speed.
A - Normal ignition voltage peak (spark plug is good).
B - Low voltage peak is an indication of a closed plug gap.
C
- High voltage peak indicates an open plug gap.
< Long combustion period (indicates small spark plug gap).
~i,+i!,~,i~tiii~iit~~,t1!lc,',l~~4~l~,~,l,~+~{+',,l 1W W Sl ,@ 10 :o 9 20 21 10 0

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< 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

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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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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)

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I Battery, Starter, Alternator
- Check for battery voltage at terminal 50 of starter motor with
key in start position. If voltage is not present, check wiring be-
tween ignition switch and starter terminal. Check the EWS
system and other inputs that disrupt terminal
56 to the start-
er. See ELE Electrical
Wiring Diagrams. If voltage is
present and no other visible wiring faults can be found, prob-
lem is most likely in starter motor.
Starter, removing and installing
(6-cylinder engine)
The starter is removed from below. Access to starter bolts is
difficult. Be sure to have the proper tools on hand before pro-
ceeding.
NOTE-
Access to the starter wiring is very limited. Forbetteraccess,
it may be necessary to remove the intake manifold.
- Disconnect negative (-) battery cable.
CAUTIOI\C
Prior to disconnecting the battern read the baltery discon-
nection cautions
in OOlGeneral Cautions and Warnings.
Remove complete air filter hous~ng:
Loosen intake duct hose clamp (A) at throttle assembly.
Loosen clamp and remove idle control hose from intake
duct
(B) and disconnect idle speed control valve electrical
harness connector.
Disconnect electrical harness connector
(C) from mass air
flow sensor.
Remove air filter housing mounting screw (D)
Disconnect vent tube
(E).
Loosen air intake duct clamp (F).
Carefully lift air filter housing out of engine bay.
Disconnect throttle cable.
Raise vehicle and support safely.
WARNING-
Make sure the car is stable and well supported at all times.
Use a professional automotive
lift orjack stands designed for
the purpose. A
floorjaclc is not adequate support
- Working underneath car, remove engine splash shield
- Disconnect fuel lines and harness connectors from retaining
brackets, as necessary.

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130-1
130 Fuel injection
General ........................... .I3 0.2
Tools and test equipment .............. .I3 0.3
Warnings and cautions ................ .I3 0.5
Fuel Supply ....................... .I3 0.6
Relieving system fuel pressure .......... .I3 0.6
Siemens MS 41 . 1. ................... 1 30-7
ECM relay. testing .................... .I3 0.7
Mass air flow (MAF) sensor.
checking and replacing
................ .I3 0.9
Engine coolant temperature (ECT) sensor.
testing and replacing
.................. 130-10
Intake air temperature (IAT) sensor.
testing and replacing
................. .I3 0.1 1
Throttle position sensor (TPS).
testing and replacing
.................. 130-1 2
ldle speed control valve.
checking and replacing
............... .I3 0.1 3
Fuel injectors. checking and replacing .... 130-15
Evaporative emissions. overview ....... .I3 0.1 6
Secondary air injection. overview ....... .I3 0-17
Engine control module (ECM).
removing and installing
................ 130-18
Siemens MS 41.1 ECM pin assignments . .I3 0.19
Siemens MS 42.0 and MS 43.0. ..... .I3 0.23
ECM relay. testing ................... .I3 0.27
Mass air flow (MAF) sensor.
checking and replacing
............... .I3 0.28
Engine coolant temperature (ECT) sensor.
testing and replacing
................. .I3 0.30
Intake air temperature (IAT) sensor.
testing and replacing
................. .I3 0.31
MS 42.0 throttle valve assembly. replacing . 130-32
MS 43.0 throttle valve assembly. replacing . 130-35
Throttle cable. adjusting (MS 42.0) ...... .I3 0.38
ldle speed control valve. checking
and replacing
....................... .I3 0.38
Evaporative emissions control diagrams . . 130- 39
Evaporative emissions control.
(MS
42.0 and MS 43.0). .............. .I3 0.39
Engine control module (ECM).
removing and installing
................ 130-40
Siemens MS 42.0 and MS 43.0
ECM pin assignments ................. 130-41
Bosch M5.2 (M62 up to 911997)
BOSC~ M5.2.1 (M62 911997 to 911998) 130-46
M5.2 system features ................. 130-47
M5.2.1 system features ............... 130-47
ECM relay. testing ................... 130-49
Oxygen sensors. checking ............. 130-51
Fuel injectors. checking and replacing .... 130-52
Mass air flow (MAF) sensor. replacing .... 130-53
ldle speed control valve. testing
and replacing
....................... 130-54
Throttle position sensor (TPS).
testing and replacing
................. 130-55
Engine coolant temperature (ECT) sensor.
testing and replacing
................. 130-55
Intake air temperature (IAT) sensor.
testing and replacing
................. 130-57
Auxiliary throttle valve (ADS) (M62 and
M62 TU engine). replacing ..... 130-57
Evaporative system pressure
leak diagnosis. overview
(5.2.1 only) ..... 130-58
Bosch 5.2 ECM pin assignments
(M62 UP to 911 997) ................... 130-59
~osch 5.2.1 ECM pin assignments
(M62 911 997 to 911 998) ............... 130-62
BOSC~ ME 7.2 ..................... 1 30-66
ME 7.2 system overview ............... 130-67
EDK adaptation ..................... 130-69
ECM relay. checking .................. 130-69
Engine coolant temperature
(ECT) sensor. testing
................. 130-71
Engine coolant temperature
(ECT) sensor. replacing
............... 130-71
Oxygen sensors. replacing ............. 130-72
Fuel injectors. removing and installing .... 130-72
Mass air flow (MAF) sensor.
removing and installing
................ 130-73
Evaporative system pressure
leak diagnosis. overview
............... 130-74
Secondary air injection. overview ........ 130-75
Bosch ME 7.2 ECM pin assignments .... 130-76

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130-2
/Fuel Injection
This repair group covers service and repair of the Bosch and
Siemens engine management systems used on
1997
through 2002 E39 models. Additional engine management
service and repair information may also be found in the fol-
lowing repair groups:
0 020 Maintenance
120 Ignition System
160 Fuel Tank and Fuel Pump
610 Electrical Component Locations
OBD On Board Diagnostics
NOTE-
Camshaft position sensor, crankshaft speed sensor and
knoclc sensors are covered in 120 Ignition System.
Table a. Engine management system applications
- - ~ ~
1 ~odellmodel year / Engine IDME system I - I
5281, 1997-1 998 IM52. 2.8 liter ISiemens MS 41 .I I 1
528i. 1999ZO00 1~52 TU, 2.8 liter ]siemens MS 42.0 I I
5251, 2001-2002 1~54, 2.5 liter 1 Siemens MS 43.0 I I
530i, 2001-2002 1~54, 3.0 liter ISiemens MS 43.0
5401 1999-2001 1~62 TU, 4.4 liter l~osch ME 7.2
I
OBI) II software and hardware is incorporated in the engine
management control systems. The
OED II system monitors
components that influence exhaust and evaporative emis-
sions. If a problem is detected, the
OED I1 system stores the
associated fault code and condition.
540i. 1997
4 If vehicle emission levels exceed 1.5 times Federally mandat-
ed criteria, the
OED II system illuminates a malfunction indi-
cator light
(MIL) in the instrument cluster.
For the
E39 cars covered by this manual, three different
MIL symbols were used, depending on year and model.
See illustration.
When faults arise, or if the malfunction indicator lamp (MIL) is
illuminated, begin troubleshooting by connecting BMW ser-
vice tester
DISplus, MoDiC, GTl or equivalent scan tool. The
capabilities of OBD
II software has the potential to save hours
540i. 1998 IM62, 4.4 liter /Bosch M5.2.1
M62, 4.4 liter Bosch M5.2