1999 BMW 540i fuel pressure

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Fuel Injection
Factory DTC scan tool
(Tool No. BMW
DISplus / GTl / MoDiC Ill)
4 Fuel line plugs
(Tool No. BMW 13
5 281 1 13 5 282)
I
4 Fuel line clamp
(Tool No. BMW 13 3
010)
4 Fuel rail to pressure gauge fitting
(Tool No. BMW
13 5 220)

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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.

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Fuel injectors, checking and replacing
The fuel injectors are electronically controlled solenoid valves
that provide precisely metered and atomized fuel into the en-
gine intake ports.
The injectors receive voltage from the ECM relay. The ECM
controls the opening by activating the ground circuit
forthe in-
jector valve solenoids. The ECM varies the duration (in milli-
seconds) of "opening" time to regulate the
airlfuel ratio.
For a quick
check of the injectors, run the engine and touch
each injector with a screwdriver or stethoscope. You should
feel a vibration or hear a buzzing
Remove fuel injection harness from injectors by unclipping
locking clip at each injector. Lift harness off injectors.
CA U JIOG
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
Use a multimeter to test injector coil resistance between in-
jector terminals.
l~uel injector coil resistance 16R at 20" C (68" F)
Disconnect negative
(-) battery cable
CAUTIOG
Prior to disconnecting the battery, read the battery discon-
nection cautionsgiven
in 001 General Warnings and Cau-
tions.
4 Remove plastic trim plugs (arrows) and fasteners, then re.
move cover from above fuel injectors.
- Disconnect vacuum line from fuel pressure regulator.
- Remove wiring harness duct mounting fasteners.

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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.

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Fuel lniection I
4 Remove complete air filter housing:
Disconnect electrical harness connector on mass air flow
sensor
(A).
Disconnect vacuum line at intake boot (B).
Loosen Intake air duct clamp (C).
Remove filter housing mounting screws
Disconnect air duct and
lift complete air filter housing and
MAF sensor out of engine compartment, pulling it forward
away from throttle housing.
- Pull throttle cable upwards out of rubber retainer and unhoolc
ball end of cable from throttle actuator.
4 Remove nuts and bolts (arrows) retaining wiring harness to
throttle housing.
- Working at throttle housing, turn harness plug counterclock-
wise and remove plug.
4 Working at side of intake manifold, disconnect electrical har-
ness connectors:
Idle control valve (A)
lntalce manifold resonance valve (B)
- Disconnect electrical harness connectors at oil pressure
sender and oil temperature sender at base of oil filter hous-
ing.
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130-36
[~uel Injection
4 Remove nuts and bolts (arrows) retaining wiring harness to
throttle housing.
- Working at throttle housing, turn harness plug countercloclc
wise and remove.
4 Working at side of intake manifold, disconnect electrical bar-
ness connectors:
Idle control valve (A)
Intake manifold resonance valve (B)
- Disconnect electrical harness connectors at oil pressure
sender and oil temperature sender at base of oil filter hous-
ing.
4 Remove dipstick guide tube:
Disconnect wiring harness brackets from tube
(A)
Unclip fuel lines from tube (B).
Remove lower guide tube mounting bolt (C).
Pull out dipstick guide tube.

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. .
Fuel Injection
Check resistance of valve across valve terminals
Idle speed control valve coil resistance
Terminals
1 and 2 20 i2.0.
Terminals 2 and 3 20 i2.0.
Terminals 1 and 3 40 i4.0.
CAUTIOIG
Be sure ignition is OFFbefore disconnecting or reconnecting
DME system components.
- To remove valve, remove cable bracket mounting bolt and
idle speed control valve mounting bracket bolts from front of
throttle housing and remove idle speed control valve with at-
tached bracket.
NOTE-
When installing idle speed control valve, remove intake boot
sealing ring from valve and install into intake air boot. Then
install valve info sealing
ring.
Evaporative emissions control diagrams
MS 42.0 (LDP) ,-a"-
Evaporative emissions control,
(MS 42.0, MS 43.0)
E39 models with MS 42.0 or MS 43.0 engine are equipped
with a fuel system evaporative pressure leak diagnosis sys-
tem. The main component of this system is the leak diagnosis
pump (LDP or DM-TL). The function of either system is to
pressurize the fuel tank and the evaporative emission system
for the purpose of detecting leaks.

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130-43
Fuel Injection ]
I I I
12 llnput IFeedback signal, engine start /Starter
Table c. Siemens MS 42.0 and MS 43.0 ECM pin assignments (continued)
I I - I
13 Input /I Alternator (generator) Notes
Throttle
valve
Crankshaft position sensor
Throttle valve (MS
42.0)
Throttle valve
Pin
6
7
8
9
10
11
14
15
16
17
18
19
20
I 1- I
23 l~round I~round, intaite air temperature sensor /Intake air temperature sensor
Signal
Output
Input
Input
Input
I I I
Component/function
Not used
Throttle valve supply potentiometer
2
Signal, crankshaft position sensor
Signal,
pedal position sensor 2 (MS 42.0)
Signal, throttle position sensor 1
Not used
Ground
Ground
Input
Ground
Ground
Input
Ground Cranltshaft position sensor
21
24
25
26
27
28
29
30
I 1- I
33 1 input ISignal, cylinder 1 fuel injector /cylinder 1 fuel injector
Ground, throttle position sensor (MS
42.0)
Ground, exhaust camshaftsensor I
Signal, pedal position sensor 1 (MS 42.0)
Ground, mass air flow sensor
Ground, intake camshaft sensor
1
Signal, throttle potentiometer 1
Ground, throttle position sensor
22 loutput I~ignal, intake air temperature Ilntake air temperature sensor
I I - I
Throttle
valve (MS 42.0)
Camshaft position sensor I
Throttle valve (MS
42.0)
Hot film mass air flow sensor
Camshaft position sensor i
Throttle valve
Throttle valve
Ground
Output
Ground Input
Output
Ground
Output
Out~ut
Ground, crankshaft position sensor
Knoclt sensor
31
34
35
36
37
38
39
Signal, coolant temperature sensor
Ground, coolant temperature sensor
Signal,
oil pressure
Signal, engine
oil temperature sensor
Ground, engine oil temperature sensor
Signal, knock sensor
Signal, knock sensor
32 loutput ISignal, ltnock sensor l~nock sensor
40
41
Coolant temperature sensor
Coolant temperature sensor
Oil pressure switch
Oil temperature sensor
Oil temperature sensor
Knoclt sensor
I Output
Input
input
Input
Input
Input
Inout
Signal, knock sensor
Input
Input Signal, cylinder
2 fuel injector
Signal, cylinder
3 fuel injector
Signal, cylinder
4 fuel injector
Signal, cylinder
5 fuel injector
Signal, cylinder
6 fuel injector
Sianai, oil level sensor Cylinder
2 fuel
injector
Cylinder
3 fuel injector
Cylinder
4 fuel injector
Cylinder
5 fuel injector
Cylinder
6 fuel injector
Oil level sensor
-
Signal. VANOS inlet valve
Signal. VANOS outlet valve VANOS
inlet valve
VANOS outlet valve