Mercedes-Benz Sprinter / Dodge Sprinter. Manual — part 411
FUEL SYSTEM
TABLE OF CONTENTS
page
page
FUEL SYSTEM
PRESSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PRESSURE FUEL LINES . . . . . . . . . . . . . . . . . 1
DIAGNOSIS AND TESTING - AIR IN FUEL
SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
DIAGNOSIS AND TESTING - INJECTOR
LEAK QUANTITY . . . . . . . . . . . . . . . . . . . . . . . 2
STANDARD PROCEDURES - CLEANING
FUEL SYSTEM COMPONENTS . . . . . . . . . . . . 3
STANDARD PROCEDURES - DRAINING
WATER FROM FUEL FILTER . . . . . . . . . . . . . . 3
PRESSURE FUEL PUMP TEST . . . . . . . . . . . . 4
. . . . . . . . . . . . . . . . . . . . . . . . . . 6
. . . . . . . . . . . . . . . . . . . . . . . . 31
FUEL SYSTEM
WARNING
WARNING - HIGH FUEL SYSTEM PRESSURE
WARNING: HIGH-PRESSURE FUEL LINES DELIVER
FUEL UNDER EXTREME PRESSURE FROM THE
INJECTION
PUMP
TO
THE
INJECTORS.
THIS
MAYBE AS HIGH AS 1600BAR (23,200PSI). USE
EXTREME CAUTION WHEN INSPECTING FOR HIGH-
PRESSURE
FUEL
LEAKS.
FUEL
UNDER
THIS
AMOUNT OF PRESSURE CAN PENETRATE SKIN
CAUSING PERSONAL INJURY OR DEATH. INSPECT
FOR HIGH-PRESSURE FUEL LEAKS WITH A SHEET
OF CARDBOARD PLACED IN THE SUSPECTED
AREA WHILE THE ENGINE IS NOT RUNNING.
START THE VEHICLE AND ALLOW THE ENGINE TO
RUN FOR A SHORT PERIOD. TURN THE ENGINE
OFF AND INSPECT THE PIECE OF CARDBOARD.
WEAR SAFETY GOGGLES AND ADEQUATE PRO-
TECTIVE CLOTHING WHEN SERVICING FUEL SYS-
TEM.
WARNING
WARNING: UNDER NO CIRCUMSTANCES SHOULD
GASOLINE BE MIXED WITH DIESEL FUEL (NOT
EVEN DURING WINTER). THE HIGH PRESSURE
PUMP IS LUBRICATED BY DIESEL FUEL. IMMEDI-
ATE FUEL SYSTEM DAMAGE MAY OCCUR CAUS-
ING
REPLACEMENT
AND
FLUSHING
OF
THE
COMPLETE DIESEL FUEL SYSTEM. HIGH PRES-
SURE PUMP SEIZURE WILL CAUSE METAL PARTI-
CLES TO SPREAD THROUGH OUT THE FUEL
CIRCUIT. ALL CDI FUEL SYSTEM COMPONENTS
CONNECTED TO THE FUEL CIRCUIT WILL HAVE TO
BE EXCHANGED AND THE LINES FLUSHED.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - HIGH PRESSURE
FUEL LINES
WARNING: HIGH-PRESSURE FUEL LINES DELIVER
FUEL UNDER EXTREME PRESSURE FROM THE
INJECTION
PUMP
TO
THE
INJECTORS.
THIS
MAYBE AS HIGH AS 1600BAR (23,200PSI). USE
EXTREME CAUTION WHEN INSPECTING FOR HIGH-
PRESSURE
FUEL
LEAKS.
FUEL
UNDER
THIS
AMOUNT OF PRESSURE CAN PENETRATE SKIN
CAUSING PERSONAL INJURY OR DEATH. INSPECT
FOR HIGH-PRESSURE FUEL LEAKS WITH A SHEET
OF CARDBOARD PLACED IN THE SUSPECTED
AREA WHILE THE ENGINE IS NOT RUNNING.
START THE VEHICLE AND ALLOW THE ENGINE TO
RUN FOR A SHORT PERIOD. TURN THE ENGINE
OFF AND INSPECT THE PIECE OF CARDBOARD.
WEAR SAFETY GOGGLES AND ADEQUATE PRO-
TECTIVE CLOTHING WHEN SERVICING FUEL SYS-
TEM.
High-pressure fuel line leaks can cause starting
problems and poor engine performance.
• Turn the engine off.
• Place a piece for cardboard in the suspected area
(Fig. 1).
• Start the engine and allow to run for a short
period.
• Turn the engine off.
• Inspect the cardboard.
VA
FUEL SYSTEM
14 - 1
If a high-pressure line connection is leaking, coun-
terhold and tighten the connection to specification
then perform this procedure again (Refer to 14 -
FUEL
SYSTEM
-
STANDARD
PROCEDURE).
Replace any damaged, restricted or leaking high-
pressure fuel lines with the correct replacement
line.
CAUTION: The high-pressure fuel lines cannot con-
tact each other or other components. Do not
attempt to weld high-pressure fuel lines or to repair
lines that are damaged. Only use the recommended
lines when replacement of high-pressure fuel line is
necessary.
DIAGNOSIS AND TESTING - AIR IN FUEL SYS-
TEM
Air will enter the fuel system whenever fuel supply
lines, separator filters, injection pump, high-pressure
lines or injectors are removed or disconnected. Air
trapped in the fuel system can result in hard start-
ing, a rough running engine, engine misfire, low
power, excessive smoke and fuel knock.
Inspect the fuel system from the fuel tank to the
injectors for loose connections (Refer to 14 - FUEL
SYSTEM - WARNING). Leaking fuel is an indicator
of loose connections or defective seals. Air can also
enter the fuel system between the fuel tank and the
fuel pump. Inspect the fuel tank module and fuel
lines for damage that might allow air into the sys-
tem.
With the DRBIII
t connected to the vehicle, select
Engine and the select Sensor Display. Page down to
view Fuel Pressure Set Point and Actual Fuel Pres-
sure. Start the engine and observe the Fuel Pressure
Set Point and the Actual Fuel Pressure. If the Actual
Fuel Pressure Oscillates above and below the Fuel
Pressure Set Point in a regular cycle, inspect the fuel
system for air intrusion.
If the Actual Fuel Pressure gradually drops below
the Fuel Pressure Set Point then spikes well above
the Fuel Pressure Set Point, replace the fuel pres-
sure soleniod (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/FUEL
PRESSURE
SOLENOID
-
REMOVAL), and recheck.
DIAGNOSIS AND TESTING - INJECTOR LEAK
QUANTITY
WARNING: REVIEW THE HIGH PRESSURE FUEL
SYSTEM WARNING BEFORE BEGINNING SERVICE
(Refer to 14 - FUEL SYSTEM - WARNING).
CRANKING TEST
NOTE: If an injector is found to be out of specifica-
tion, repeat this test procedure after the injector
replacement. Hydraulic flow will take the path of
least resistance and multiple failures may be identi-
fied.
Perform this test with the engine at operating tem-
perature, when possible. This test will assist in
determining a defective or internally leaking injec-
tor(s) is present by measuring the amount of fuel
return.
(1) Turn the ignition off.
(2) Remove the engine cover (Refer to 9 - ENGINE
- REMOVAL).
(3) Disconnect the fuel return hoses at the top of
the injectors.
(4) Pinch off the fuel return line at the banjo bolt
fitting of the fuel rail.
(5) Disconnect the fuel rail solenoid and camshaft
position sensor.
(6) Install the test vials onto the injectors and
secure with the return hose clips (Fig. 2).
Fig. 1 Typical Test for Leaks with Cardboard
1 - HIGH-PRESSURE LINE
2 - CARDBOARD
3 - FITTING
14 - 2
FUEL SYSTEM
VA
(7) Connect a scan tool, select from Main Menu,
System Select, Engine, System Tests, Fuel Quantity
Test, Engine Cranking Test and follow the screen.
(8) After ten seconds, a maximum of 2.5 ml
(between 2 & 3 graduation lines) may be reached in
the inner vials. If the level has exceeded the 2.5 ml,
replace that affected cylinder’s injector, clear the
memory using the scan tool, empty the test vials, and
retest.
RUNNING TEST
NOTE: If an injector is found to be out of specifica-
tion, repeat this test procedure after the injector
replacement. Hydraulic flow will take the path of
least resistance and multiple failures may be identi-
fied. Engine temperature must be above 80° C
(176°F) to perform the running test.
Perform this test with the engine at operating tem-
perature. This test will assist in determining a defec-
tive or internally leaking injector(s) is present by
measuring the amount of fuel return.
(1) Turn the ignition off.
(2) Remove the engine cover (Refer to 9 - ENGINE
- REMOVAL).
(3) Disconnect the fuel return hoses at the top of
the injectors.
(4) Pinch off the fuel return line at the banjo bolt
fitting of the fuel rail.
(5) Install the test vials onto the injectors and
secure with the return hose clips (Fig. 2).
(6) Connect a scan tool, select from Main Menu,
System Select, Engine, System Tests, Fuel Quantity
Test, Engine Running Test and follow the screen.
(7) After ten seconds, a maximum of five gradua-
tion lines (40 ml) of the large test vial may be
reached. If the level has exceeded the five graduation
line, replace that affected cylinder’s injector, clear the
memory using the scan tool, empty the test vials, and
retest.
STANDARD PROCEDURE
STANDARD PROCEDURES - CLEANING FUEL
SYSTEM COMPONENTS
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines, fuel rail, and fuel injection
pump. Very tight tolerances are used with these
parts. Dirt contamination could cause rapid part
wear and possible plugging of fuel injector nozzle
tip holes. This in turn could lead to possible engine
misfire. Always wash/clean any fuel system compo-
nent thoroughly before disassembly and then air
dry. DO NOT wire brush injector nozzles when
cleaning. Cap or cover any open part after disas-
sembly. Before assembly, examine each part for
dirt, grease or other contaminants and clean if nec-
essary. When installing new parts, lubricate them
with clean engine oil or clean diesel fuel only.
STANDARD PROCEDURES - DRAINING WATER
FROM FUEL FILTER
Connect a hose to the Water in Fuel (WIF) drain
and place it in a clearly marked and suitable con-
tainer. Open the WIF drain by turning counterclock-
wise (Fig. 3). Turn the ignition key on for 20 seconds
(Refer to low pressure fuel pump operation). Repeat
the procedure until all water is removed, close the
drain and remove the hose.
Fig. 2 Special Tool # 9545
1 - SPECIAL TOOL #9545
VA
FUEL SYSTEM
14 - 3
STANDARD PROCEDURE - LOW PRESSURE
FUEL PUMP TEST
NOTE: Assure fuel tank quantity and proper fuel
gauge operation. Assure that the fuel pump fuse or
relay is not open. Capture any fuel spillage and
store in appropriately marked containers.
NOTE: When the ignition switch is turned to the ON
position the fuel pump will begin to run for 20–30
seconds and then it stops.
The low pressure pump draws fuel out of the fuel
tank module and pushes the fuel towards the fuel fil-
ter. If the pressure reading is below specification,
look for damaged or leaking fuel lines or a restricted
fuel filter. If no problem is found with the fuel sys-
tem replace the low pressure fuel pump.
(1) Disconnect the negative battery cable.
(2) Connect a fuel gauge to the low pressure fuel
supply to the high pressure pump (Fig. 4).
(3) Connect negative battery cable.
(4) Turn the ignition to the ON position and
observe the fuel gauge reading (Fig. 5).
(5) The fuel pressure should be 4.0 to 4.5 bar (58 -
65 psi) If the fuel pressure is below specification,
Fig. 3 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
Fig. 4 FUEL GAUGE CONNECT AT HIGH PRESSURE
PUMP
1 - FUEL SUPPLY FITTING
2 - ADAPTOR
3 - FUEL GAUGE HOSE
4 - HIGH PRESSURE PUMP
5 - FUEL RETURN FITTING
Fig. 5 FUEL PRESSURE TEST AT HIGH PRESSURE
PUMP
14 - 4
FUEL SYSTEM
VA
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