Check low-pressure fuel circuit

AR07.15-G-2000CI

Check low-pressure fuel circuit

27.08.2020

Engine

457.9, 458.9 in model 000.001

 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

 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

Notes on possible sources of fault in the low-pressure fuel circuit

AH07.15-N-1000-02C



Check

1

Clean and dry fuel lines, connections, threaded connections, and component parts.

2

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

3

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

If parts are rejected or in the event of leaky areas,



replace corresponding component part or seal connection.

4

Open cap on fuel tank.

5

Clean fuel prefilter element.

Only for fuel systems with fuel prefilter.

6

Check fuel filter element.



Engines without fuel preheating and water separator

AP47.20-G-0780CH



Engines with fuel preheating and water separator

AP47.20-G-0790CH

 Collect escaping fuel.

If strong contamination is present,



replace fuel filter element.

7

Start engine and warm up to operating temperature.

 The fuel temperature in the fuel tank must be   40 °C.

8

Check for leaks in low-pressure fuel circuit.

Only if the engine starts badly.

AR07.15-G-2000-04CI

Pressure drop in low-pressure fuel circuit

*BE47.00-N-1003-01E

 Banjo bolt, fuel line to fuel filter housing

*BA47.25-N-1004-01L

 Banjo bolt, fuel line to fuel heat exchanger

*BA47.25-N-1009-01L

 Banjo bolt, fuel line to solenoid valve of flame starting system or banjo bolt for fuel filter housing

*BA47.25-N-1015-01L

 High-pressure hose

*123589042118

 Tester

*541589022100

 Adaptation parts

*541589009100

9

Measure fuel pressure downstream of the fuel filter.

Only for engines with poor engine output.

AR07.15-G-2000-02CI

Fuel pressure downstream of fuel filter

*BE47.00-N-1001-01E

 Banjo bolt, fuel line to fuel filter housing

*BA47.25-N-1004-01L

 Banjo bolt, fuel line to solenoid valve of flame starting system or banjo bolt for fuel filter housing

*BA47.25-N-1015-01L

 High-pressure hose

*123589042118

 Tester

*541589022100

 Adaptation parts

*541589009100

If the fuel pressure downstream of the oil pressure measurement is too high,



Measure fuel return quantity at the fuel tank

AR07.15-G-2000-03CI

Fuel return quantity at fuel tank

*BE47.00-N-1002-01E

If the fuel pressure downstream of the oil pressure measurement is too low,



Measure fuel intake pressure upstream of fuel pump

AR07.15-G-2000-05CI

Fuel intake pressure upstream of fuel pump

*BE47.00-N-1004-01E

 Banjo bolt, fuel line to fuel heat exchanger

*BA47.25-N-1009-01L

 Tester

*617589042100

 Clamp

*000589403700

 Adaptation parts

*541589009100

10

Close cap on fuel tank.

11

Start engine and bleed fuel system.

 The fuel system is bled automatically. Run engine for approx. 1 minute.

If the engine does not start, or runs only for a short time,



Bleed fuel system

AR47.00-G-1720CI

Fuel circuit check values

Number

Designation

ENGINE 457.9, 458.9

BE47.00-N-1001-01E

Fuel pressure downstream of fuel filter

Idling speed

bar

1,8...2,8

Breakaway speed

bar

6,2...7,2

Fuel circuit check values

Number

Designation

ENGINE 457.9, 458.9

BE47.00-N-1002-01E

Fuel return quantity at fuel tank

Idling speed

l/min

1,1...1,5

Breakaway speed

l/min

2,2...2,8

Fuel circuit check values

Number

Designation

ENGINE 457.9, 458.9

BE47.00-N-1003-01E

Pressure drop in low-pressure fuel circuit

Test period

min

5

Test pressure

bar

5,0

Pressure drop

bar

0

Fuel circuit check values

Number

Designation

ENGINE 457.9, 458.9

BE47.00-N-1004-01E

Fuel intake pressure upstream of fuel pump

Breakaway speed

bar

–0,30...–0,15

 Fuel lines/hoses

Number

Designation

Engine 457.9, 458.9

BA47.25-N-1004-01L

Banjo bolt, fuel line to fuel filter housing

Nm

50

 Fuel lines/hoses

Number

Designation

Engine 457.9, 458.9

BA47.25-N-1009-01L

Banjo bolt, fuel line to fuel heat exchanger

Nm

50

 Fuel lines/hoses

Number

Designation

Engine 457.9, 458.9

BA47.25-N-1015-01L

Banjo bolt, fuel line to solenoid valve of flame starting system or banjo bolt for fuel filter housing

Nm

15