fuel MERCEDES-BENZ SPRINTER 2006 Service Manual

FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module (Fig.
29). The sending unit consists of a float, an arm, and
Fig. 26 FUEL TANK ASSEMBLY
1 - Strap Bolts (2)
2 - Hose (not with all engines)
3 - Fuel Outlet Line
4 - Fuel Return Line
5 - Plug
6 - Fuel Tank
7 - Tank Straps (2)8 - Nuts (2)
9 - Filler Tube
10 - Vent Hose
11 - Hose
12 - Clamps
13 - Cushioning Material
14 - Two-Way Valve
Fig. 27 FUEL COOLER LINES
1 - Expansion Tank
2-TopofTank
3 - Thermostat (Preheating Valve)
4 - Cooler Lines
5 - Connecting Hoses/Clamps
Fig. 28 FUEL LINE PLIERS-9539
14 - 28 FUEL DELIVERYVA

a variable resistor track (card).
REMOVAL
The fuel level sending unit (fuel level sensor) and
float assembly is located on the side of the fuel pump
module (4) (Fig. 30).
(1) Remove fuel pump module from fuel tank.
Refer to Fuel Pump Module Removal/Installation.
(2) Unplug sensor's 2±wire harness from pump
module electrical connector.
(3) Before disconnecting wiring from 2±wire har-
ness electrical connector, note position of each wire in
the connector. Record this position.
(4) Disconnect wiring from 2±wire harness electri-
cal connector using a terminal pick / removal tool.
Refer to Special Tools in 8W, Wiring for tool part
numbers.
(5) To remove sending unit from pump module,
press on plastic locking tabs (1) (Fig. 30) while slid-
ing sending unit (4) on its tracks.
INSTALLATION
(1) Noting their previous positions, connect wires
from 2±wire harness into its connector.
(2) Plug 2±wire harness connector into pump mod-
ule electrical connector.
(3) Position sending unit (4) (Fig. 31) to tracks on
fuel pump module. Slide and snap into place.
(4) Install fuel pump module. Refer to Fuel Pump
Module Removal/Installation.
Fig. 29 FUEL LEVEL SENSOR
1 - RELEASE TABS
2 - ELECTRIC FUEL PUMP
3 - BOTTOM OF FUEL PUMP MODULE
4 - SENDING UNIT
Fig. 30 FUEL LEVEL SENSOR
1 - RELEASE TABS
2 - ELECTRIC FUEL PUMP
3 - BOTTOM OF FUEL PUMP MODULE
4 - SENDING UNIT
Fig. 31 FUEL LEVEL SENSOR
1 - RELEASE TABS
2 - ELECTRIC FUEL PUMP
3 - BOTTOM OF FUEL PUMP MODULE
4 - SENDING UNIT
VAFUEL DELIVERY 14 - 29

WATER IN FUEL SENSOR
DESCRIPTION
The water in fuel sensor (WIF) is located in the
fuel filter housing (Fig. 32). The sensor detects the
presence of water in the fuel. If water is present in
the fuel a signal is sent to the ECM and the ECM
signals the instrument cluster, over the CAN bus, to
illuminate the water in fuel warning.
OPERATION
The non-dielectric properties of the water allow the
sensors probes to close the electronic circuit when
water is present in the system. When diesel fuel is
present in the system, it's dielectric (does not conduct
electricity well) properties do not allow any electrical
contact between the probes. A 12V power signal is
always present in order to illuminate the indicator on
the instrument cluster. For removal and installation
procedure refer to (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL FILTER - REMOVAL).
Fig. 32 WATER IN FUEL SENSOR
1 - WIF SENSOR
2 - WIF DRAIN
3 - FUEL FILTER
4 - FUEL SUPPLY FROM TANK
5 - FUEL SUPPLY TO HIGH PRESSURE PUMP
14 - 30 FUEL DELIVERYVA

FUEL INJECTION
TABLE OF CONTENTS
page page
ACCELERATOR PEDAL POSITION SENSOR
DESCRIPTION.........................32
REMOVAL.............................32
INSTALLATION.........................32
BOOST PRESSURE SENSOR
DESCRIPTION.........................33
OPERATION...........................33
DIAGNOSIS AND TESTING - BOOST
PRESSURE SENSOR..................33
REMOVAL.............................33
INSTALLATION.........................33
CAMSHAFT POSITION SENSOR
DESCRIPTION.........................33
OPERATION...........................34
REMOVAL.............................34
INSTALLATION.........................34
CRANKSHAFT POSITION SENSOR
DESCRIPTION.........................35
OPERATION...........................35
REMOVAL.............................35
INSTALLATION.........................35
FUEL INJECTOR
DESCRIPTION
FUEL INJECTOR......................35
OPERATION...........................36
STANDARD PROCEDURE
STANDARD PROCEDURE - INJECTOR
CLASSIFICATION.....................37
CLEANING FUEL INJECTORS............38
REMOVAL.............................38
INSTALLATION.........................39
FUEL PRESSURE SENSOR
DESCRIPTION.........................39
OPERATION...........................39REMOVAL.............................39
INSTALLATION.........................40
FUEL PRESSURE SOLENOID
DESCRIPTION.........................40
OPERATION...........................40
STANDARD PROCEDURE - FUEL PRESSURE
SOLENOID TEST......................41
REMOVAL.............................41
INSTALLATION.........................41
FUEL TEMPERATURE SENSOR
DESCRIPTION.........................42
OPERATION...........................42
REMOVAL.............................42
INSTALLATION.........................42
INTAKE AIR TEMPERATURE SENSOR
DESCRIPTION.........................42
OPERATION...........................43
REMOVAL.............................43
INSTALLATION.........................43
INTAKE AIR PRESSURE SENSOR
DESCRIPTION.........................43
OPERATION...........................43
REMOVAL.............................43
INSTALLATION.........................44
MANIFOLD AIR FLOW (MAF) SENSOR
DESCRIPTION.........................44
OPERATION...........................44
REMOVAL.............................44
INSTALLATION.........................45
O2 SENSOR
DESCRIPTION.........................45
OPERATION...........................45
REMOVAL.............................48
INSTALLATION.........................48
VAFUEL INJECTION 14 - 31

ACCELERATOR PEDAL POSI-
TION SENSOR
DESCRIPTION
The accelerator pedal position sensor (Fig. 1) is
located on the accelerator pedal assembly. The driver
supplies the torque requirements for the engine by
operating the accelerator pedal in accordance with
the desired speed or acceleration. The pedal sensor
converts the mechanical operation of the pedal into
an electrical signal and sends the information to the
ECM. The ECM adjusts the quantity of the fuel that
is injected into the engine.
The accelerator pedal position sensor is serviced as
an assembly with the accelerator pedal assembly.
REMOVAL
(1) Disconnect the negative battery cable.
(2) Disconnect the APP sensor electrical connec-
tors.
(3) Remove the APP sensor fasteners and the sen-
sor (Fig. 2).
INSTALLATION
(1) Connect the accelerator pedal position sensor
wiring harness connector.
Fig. 1 ACCELERATOR PEDAL POSITION SENSOR
1 - APP SENSOR
2 - ACCELERATOR PEDAL
3 - BRAKE PEDAL
Fig. 2 ACCELERATOR PEDAL POSITION SENSOR
1 - APP SENSOR
2 - ACCELERATOR PEDAL
3 - BRAKE PEDAL
Fig. 3 ACCELERATOR PEDAL POSITION SENSOR
1 - APP SENSOR
2 - ACCELERATOR PEDAL
3 - BRAKE PEDAL
14 - 32 FUEL INJECTIONVA

(2) Position the sensor (Fig. 3) and install the fas-
teners.
(3) Connect the negative battery cable.
BOOST PRESSURE SENSOR
DESCRIPTION
The boost pressure sensor is mounted to the charge
air pipe (Fig. 4). The sensor allows the ECM to mon-
itor intake air down stream of the turbocharger.
OPERATION
When the intake manifold pressure is high due to
turbo boost, sensor voltage output is 2.0-4.7 volts.
The sensor receives a 5-volts reference from the
ECM. Sensor ground is also provided by the ECM.
The ECM uses boost pressure combined with intake
air temerature to determine the volume of air enter-
ing the engine (Fig. 4).
DIAGNOSIS AND TESTING - BOOST PRESSURE
SENSOR
If the boost pressure sensor fails, the ECM records
a DTC into memory and continues to operate the
engine in one of the three limp-in modes. When the
ECM is operating in this mode, a loss of power will
be present, as if the turbocharger was not operating.
The best method for diagnosing faults with the boost
pressure sensor is with the DRB IIItscan tool. Refer
to the Diesel Powertrain Diagnostic Manual for more
information.
Refer to On-Board Diagnostics in Emissions Con-
trol System for a list of Diagnostic Trouble Codes
(DTC's) for certain fuel system components.
REMOVAL
(1) Disconnect the negative battery cable.
(2) Unplug the electrical connector.
(3) Remove the sensor retaining bolts, remove the
sensor (Fig. 5) and O-ring.
INSTALLATION
(1) Inspect boost pressure sensor O-ring for cuts or
abrasions, replace as necessary.
(2) Position the boost pressure sensor above access
hole in the charge air pipe and push down to fit flush
(Fig. 21).
(3) Install the bolts and tighten to 44 lbs. in. (5
N´m) (Fig. 21).
(4) Reconnect the sensor electrical connector (Fig.
21).
(5) Connect negative battery cable
CAMSHAFT POSITION SEN-
SOR
DESCRIPTION
The camshaft position sensor is mounted on the
cylinder head cover toward the rear of the engine.
The camshaft sensor (Fig. 6) utilizes a non contact
method on one segment of the camshaft to record the
camshaft position. When the ECM receives the signal
from this sensor, it can then detect TDC of cylinder
number one. The signal from the camshaft sensor is
only required during engine starting. Injection timing
Fig. 4 BOOST PRESSURE SENSOR
Fig. 5 BOOST PRESSURE AND INLET AIR
TEMPERATURE SENSORS
1 - CHARGE AIR DUCT
2 - INTAKE AIR TEMPERATURE SENSOR
3 - BOOST PRESSURE SENSOR
VAFUEL INJECTION 14 - 33

is synchronized by means of the camshaft signal and
the crankshaft signal.
OPERATION
On the camshaft sensor's signal line, a high signal
correspons to a voltage of 0-5V. If the segment
machined into the exhaust camshaft sprocket is posi-
tioned opposite the camshaft sensor, the camshaft
signal is low, approximately 0V. This signal is used
by the engine control module (ECM) for detecting
ignition TDC of cylinder 1 as the engine rotates. If no
signal is supplied by the camshaft position sensor,
the vehicle will not start because cylinder order can
not be detected.
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove engine cover
(3) Disconnect camshaft position sensor electrical
connector (Fig. 7).
(4) Remove retaining bolt and remove sensor (Fig.
7).
INSTALLATION
(1) Install camshaft position sensor and tighten
bolt (Fig. 8).
(2) Reconnect electrical connector (Fig. 8).
Fig. 6 CAMSHAFT POSITION SENSOR
Fig. 7 CAM POSITION SENSOR
1 - WIRING HARNESS CONNECTOR
2 - CAM POSITION SENSOR
3 - O-RING
4 - CYLINDER HEAD COVER
Fig. 8 CAM POSITION SENSOR
1 - WIRING HARNESS CONNECTOR
2 - CAM POSITION SENSOR
3 - O-RING
4 - CYLINDER HEAD COVER
14 - 34 FUEL INJECTIONVA

(3) Install engine cover.
(4) Reconnect negative battery cable.
CRANKSHAFT POSITION SEN-
SOR
DESCRIPTION
The crankshaft position sensor is located opposite
the teeth on the flywheel and uses a non contact
method to record the position of the crankshaft. The
leading edges of each tooth on the flywheel generate
a positive signal in the position sensor, while the
trailing edges generate a negative signal. When the
crankshaft is rotating, an alternating voltage is pro-
duced as a result.
The period of the signal is the time required by the
crankshaft to turn through the gap between two fly-
wheel teeth. The clearance between the crankshaft
position sensor and the teeth of the flywheel is fixed
by the installation.
Two teeth on the flywheel are missing. The result-
ing signal gap is used by the ECM to detect the TDC
position of cylinder number one.
OPERATION
The clearance between the crankshaft position sen-
sor and the flywheel are fixed by the installation
position. Two teeth on the flywheel are missing. The
resulting gap is used by the ECM to detect DTC of
cylinder number one. The crankshaft position is cal-
culated to an accuracy of a fraction of a degree so
that the start and end of injection can occur at
exactly the right moment. The engine speed signal is
also processed by the ECM from the crankshaft sen-
sor. This signal is then transferred to other control
modules over the CAN bus.
If the crankshaft position sensor fails, the ECM
will stop triggering the injectors, the engine will
stall, the engine warning light may or may not illu-
minate, but the engine will not restart.
REMOVAL
(1) Disconnect the negative battery cable.
(2) Unplug the crankshaft wiring harness connec-
tor.
(3) Remove the crankshaft sensor retaining bolt
and remove sensor (Fig. 9).
INSTALLATION
(1) Position the crankshaft position sensor into the
access hole and install retaining bolt.
(2) Tighten the retaining bolt to 80 lbs. in. (9 N´m)
(Fig. 9).
(3) Connect crankshaft position sensor wiring har-
ness connector (Fig. 9).
(4) Connect negative battery cable.
FUEL INJECTOR
DESCRIPTION
FUEL INJECTOR
There are individual fuel injectors for all five cyl-
inders. Each injector nozzle has seven holes. The fuel
injectors are used to spray fuel into the combustion
chamber. Each injector has a six digit alphanumeric
code on the injector top which must be entered into
to ECM using the DRBIIIt(Fig. 10). Specific moving
parts inside the injector are graphite coated to assist
with the lubrication process.
Fig. 9 CRANKSHAFT POSITION SENSOR
1 - ENGINE BLOCK
2 - WIRING HARNESS CONNECTOR
3 - CRANKSHAFT POSITION SENSOR
4 - STARTER SOLENOID
VAFUEL INJECTION 14 - 35

OPERATION
The injector operation can be subdivided into four
operating states with the engine running and the
high-pressure pump generating pressure:
²Injector closed (with high pressure applied)
²Injector opens (start of injection)
²Injector opened fully
²Injector closes (end of injection)
Injector closed (with high pressure applied)
With the injector closed (at-rest state), the solenoid
valve is not energized and is therefore closed. With
the bleed orifice closed, the valve spring forces the
armature's ball onto the bleed-orifice seat. The rail's
high pressure build up in the valve control chamber,
and the same pressure is also present in the nozzle's
chamber volume. The rail pressure applied at the
control plunger's end face, together with the force of
the nozzle spring, maintain the nozzle in the closed
Fig. 10 FUEL INJECTOR
1 - FUEL INJECTOR
2 - NOZZLE
3 - FUEL INLET FITTING
4 - ELECTRICAL CONNECTION
Fig. 11 INJECTOR COMPONENTS
1 - INJECTOR CLOSED (AT-REST STATUS)
2 - ELECTRICAL CONNECTION
3 - TRIGGERING ELEMENT (SOLENOID VALVE)
4 - FUEL INLET (HIGH PRESSURE) FROM THE RAIL
5 - VALVE BALL
6 - BLEED ORIFICE
7 - FEED ORIFICE
8 - VALVE CONTROL CHAMBER
9 - VALVE CONTROL PLUNGER
10 - FEED PASSAGE TO THE NOZZLE
11 - NOZZLE NEEDLE
14 - 36 FUEL INJECTIONVA

position against the opening forces applied to its
pressure stage (Fig. 11).
Injector opens (start of injection)
The solenoid valve is energized with the pickup
current which serves to ensure that it open quickly.
The force exerted by the triggered solenoid now
exceeds that of the valve spring and the armature
opens the bleed orifice. Almost immediately, the high-
level pick-up current is reduced to the lower holding
current required for the electromagnet. This is possi-
ble due to the magnetic circuit's air gap now being
smaller. When the bleed orifice opens, fuel can flow
from the valve control chamber into the cavity situ-
ated above it, and from there via the fuel return to
the tank. The bleed orifice prevents complete pres-
sure balance, and the pressure in the valve control
chamber sinks as a result. This leads to the pressure
in the valve-control chamber being lower than that in
the nozzle's chamber volume which is still at the
same pressure level as the rail. The reduced pressure
in the valve-control chamber causes a reduction in
the force exerted on the control plunger, the nozzle
needle open as a result, and injection starts (Fig. 11).
Injector opens fully
The control plunger reaches its upper stop where it
remains supported by a cushion of fuel which is gen-
erated by the flow of fuel between the bleed and feed
orifices. The injector nozzle has now opened fully,
and the fuel is injected into the combustion chamber
at a pressure almost equal to that in the fuel rail
(Fig. 11).
Injector closes (end of injection)
As soon as the solenoid valve is no longer trig-
gered, the valve spring forces the armature down-
wards and the ball closes the bleed orifice. The
armature is a 2±piece design. Here, although the
armature plate is guided by a driver shoulder in its
downward movement, it can ªoverspringº with the
return spring so that it exerts no downwards-acting
forces on the armature and the ball. The closing of
the bleed orifice lead to pressure build up in the con-
trol chamber via the input from the feed orifice. This
pressure is the same as that in the rail and exerts an
increased force on the control plunger through its
end face. This force, together with that of the spring,
now exceeds the force exerted by the chamber volume
and the nozzle needle closes. Injection ceases as soon
as the nozzle needle comes up against its bottom stop
again (Fig. 11).
STANDARD PROCEDURE
STANDARD PROCEDURE - INJECTOR CLASSI-
FICATION
NOTE: Fuel Injectors have different flow rates.
When ALL injectors are removed, re-enter all injec-
tor six digit codes.
The classification of injectors into 3 classes
describes the quantity characteristic of the injector.
This will make it possible in the future to match the
engine software to the tolerances of the injector
within a more narrowly graduated range. Classifica-
tion can be clearly recognized, and assigned only by
means of a DRBIIIt.
Classified injectors can be recognized by the six-
digit alphanumeric code or part number and identifi-
cation on the magnetic head (circle with a number
between 1 and 3 inside) (Fig. 12). The number corre-
sponds to the classification stage.
These general conditions equally apply if, as a
result of replacing an engine, carrying out repairs to
the cylinder head etc., the cylinder selective assign-
ment of the injectors or the engine control module
assignment may have changed. If proper attention is
not paid to the classification on these vehicles drive-
ability and smoking concerns could result.
If an injector is replaced, it is then necessary to
assign the classification number to the corresponding
cylinder with theDRBIIItin the control module.
Fig. 12 INJECTOR CLASSIFICATION MARKINGS
1 - ELECTRICAL CONNECTOR
2 - SIX-DIGIT ALPHANUMERIC CODE
VAFUEL INJECTION 14 - 37