Check low-pressure fuel circuit

AR07.15-G-2000CJ

Check low-pressure fuel circuit

27.08.2020

Engine

541.9, 542.9, 941.9, 942.9 in model 000.001

4

Fuel heat exchanger

5

Fuel pump (FP)

6

Fuel filter

7

Nozzle holder combination

8

Pump-line-nozzle system unit pump

10

Overflow valve

A

Fuel feed (intake side)

B

Fuel feed (thrust side)

C

Fuel high pressure side (injection line) downstream of unit pump (PLD)

D

Fuel return downstream of unit pump (PLD)

E

Fuel purging quantity

F

Fuel return (leak fuel)

1

Fuel tank

11.2

Fuel return connector coupling

1.1

Fuel strainer (800 μm)

12

Restrictor (0.5 mm) in flame starting system fuel line

2

Fuel prefilter ((300 μm) with hand pump)

30

Fuel temperature sensor

3.1

Plug-on valve in fuel feed (locked in open position)

33

Glow plug

3.2

Plug-on valve in fuel return (locked in open position)

35

Flame starting system solenoid valve

4

Fuel heat exchanger

A

Fuel feed (intake side)

5

Fuel pump (FP)

B

Fuel feed (thrust side)

5.1

Overpressure valve (9.0...12.0 bar)

C

Fuel high pressure side (injection line) downstream of unit pump (PLD)

6

Fuel filter (5 μm)

D

Fuel return downstream of unit pump (PLD)

6.1

Fuel filter drain valve

E

Fuel purging quantity

6.2

Continuous balance bore in fuel filter (0.7 mm)

F

Fuel return (leak fuel)

7

Nozzle holder combination

G

Manometer test

8

Unit pump (PLD)

H

Fuel return quantity test

9

Banjo union with continuous balance bore (0.7 mm)

I

Fuel pressure downstream of fuel filter test point

10

Overflow valve (up to engine end no. 092407: 2.0 bar; as of engine end no. 092408: 2.65 bar)

II

Fuel return quantity at fuel tank test point

10.1

Restrictor (3.1 mm) in overflow valve

III

Low-pressure fuel circuit leak tightness test point

11.1

Fuel feed connector coupling

IV

Fuel intake pressure upstream of fuel pump test point

 Danger

Risk of explosion caused by fuel igniting, risk of poisoning caused by inhaling and swallowing fuel as well as risk of injury to eyes and skin caused by contactwith fuel.

No fires, sparks, open flames or smoking. Pour fuels into suitable and appropriately marked containers only.
Wear protective clothing when handling fuel.

AS47.00-Z-0001-01A

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

Note on calculation of tightening torque when using insertion or socket tools with various effective lengths

AH00.00-P-0015-01CW

 

Remove/install

1

Clean and dry fuel lines, connections, threaded connections and components.

2

Allow engine to run for approx. 2 to 3 min at maximum governed engine speed.

3

Perform visual check of all fuel lines, connections, threaded connections and component parts.

If parts are complained about or in the case of leaky locations,



replace corresponding component part or seal connection.

4

Clean fuel prefilter element.

Only for fuel systems with fuel prefilter.



AP47.20-G-0730CI

5

Check fuel filter element.



Engines without fuel preheating and water separator

AP47.20-G-0780CI



Engines with fuel preheating and water separator

AP47.20-G-0790CH

 Collect escaping fuel.

If severe contamination is present,



replace fuel filter element.

6

Open cap at fuel tank (1).

7

Connect vehicle diagnosis system and read out fault memory.

 See information from body manufacturer.

8

Parameterize up idle rpm limitation using vehicle diagnosis system to 4000 rpm.

Only for engines with idle rpm limitation.

 Note previously set value of idle rpm limitation.

9

Disconnect fuel lines at fuel prefilter (2) and connect with each other.

Only with installed fuel prefilter (2) and only for test duration.



Check

10

Install test and measuring equipment at low-pressure fuel circuit.

Only for test of fuel pressure downstream of fuel pump (5).

AR07.15-G-2000-22CI

 Banjo bolt, fuel line to fuel filter housing

*BA47.25-N-1004-01L

 High-pressure hose

*123589042118

 Tester

*541589022100

 Adaptation parts

*541589009100

11

Check fuel pressure downstream of fuel filter (6).



AD07.15-G-7001-01A

 Test conditions:
The engine must be at operating temperature.
The fuel temperature in the fuel tank (1) must be  40 °C.
Bubble-free fuel must flow through for the tests.

 Collect escaping fuel.

 If the fuel pressure is OK, no further tests may be performed.

If the fuel pressure lies outside the tolerance,



measure the fuel return (F) quantity at fuel tank (1).



MR (PLD) test of hydraulic system fuel return flow quantity at fuel tank

AD07.15-G-7001-04A

12

Install test and measuring equipment at low-pressure fuel circuit.

Only for leak test of fuel system.

AR07.15-G-2000-23CI



Plug for fuel line

WF58.50-W-4725-01A

 Banjo bolt, fuel line to fuel filter housing

*BA47.25-N-1004-01L

 High-pressure hose

*123589042118

 Tester

*541589022100

 Adaptation parts

*541589009100

13

Check for leaks in low-pressure fuel circuit.



AD07.15-G-7001-08A

14

Install test and measuring equipment at low-pressure fuel circuit.

Only for test of fuel pressure upstream of fuel pump (5).



Plug for fuel line

WF58.50-W-4725-01A

AR07.15-G-2000-21CI

 Banjo bolt, fuel suction line to fuel pump

*BA47.25-N-1007-01L

 Tester

*617589042100

 Clamp

*000589403700

15

Check fuel intake pressure upstream of fuel pump (5).



AD07.15-G-7001-03A

16

Parameterize down idle rpm limitation using vehicle diagnosis system.

 To previously set (noted) value of idle rpm limitation.

17

Install in the reverse order

18

Bleed fuel system.

AR47.00-G-1720CI

 Fuel lines/hoses

Number

Designation

ENGINE 541.9, 542.9, 941.9, 942.9

BA47.25-N-1004-01L

Banjo bolt, fuel line to fuel filter housing

Nm

50

 Fuel lines/hoses

Number

Designation

ENGINE 541.9, 542.9, 941.9, 942.9

BA47.25-N-1007-01L

Banjo bolt, fuel suction line to fuel pump

Nm

50