ar0715l2000d

Testing the low pressure fuel circuit

Type ar · topic 07.15 · version 0300 · 2005-06-08

Applies to: ENGINES 904.904 /908 ## up to 040487

Where it sits

Function group 1 Engine › 07 Mixture formation › 07.15 Diesel injection system (PLN), Engine control (MR) — Series 904 (models 904, 908)

EinPAS 16 Fuel/power supply to engine › 16.10 Fuel supply › 16.10.1 Basic information — Series 904 (models 904, 908)

AR07.15-L-2000D

Testing the low pressure fuel circuit

26.5.99

ENGINES 904.904 /908 ## up to 040487

Testing the low pressure fuel circuit

W07.15-1014-09

1 Fuel delivery pump (KFP)

1.1 Pressure limiting valve in fuel delivery pump (9.2 bar)

1.2 Check valve in fuel delivery pump (0.2 bar)

2 Fuel filter (KF)

2.1 Fuel filter drain valve

2.2 Constant vent in fuel filter (as of engine end no. 027211)

3.1 Bypass from fuel feed passage to fuel return passage

5 Nozzle holder combination

8 overflow valve up to engine end no. 002 604 6.5 bar
from engine end no. 002 605 4.5 bar

8.1 Constant vent (0.5 mm)

10 PLD unit pumps (Y6 to Y11)

12 Fuel prefilter (KVF)

12.1 Check valve in fuel prefilter

14.1 Assembly valve in fuel feed (opened by pressure)

15.1 Assembly valve in fuel return flow (opened by pressure)

17 Fuel tank

17.1 Air admission valve

18.1 Restrictor (0.5 mm) in flame starting fuel line

-----------------------------------------------------------------------------------------

18.2 Restrictor (threaded restrictor) in flame starting fuel line

19 Short circuit line with valve

20 Fuel hand priming pump

21 Fuel heat exchanger

B10 Fuel temperature sensor

R3 Flame starting glow plug

Y5 Solenoid valve

Fuel circuit

A Fuel feed (inlet vacuum side)

B Fuel return (leak fuel)

C Fuel feed (pressure side)

D Fuel high pressure side (downstream of PLN unit pumps)

E Fuel return (fuel filter drain)

----- Fuel passages in crankcase

Fuel lines

-----------------------------------------------------------------------------------------

Test points, test data

G Manometer test

H Test of fuel return flow quantity

I Fuel pressure downstream of fuel filter

Idle speed: up to engine end no. 002604 6.0 bar,
from engine end no. 002605 4.3 bar

Limit speed: up to engine end no. 002604 6.2 to
7.5 bar,
from engine end no. 002605 4.0 to 6.5 bar

II Fuel return flow quantity at nozzle holder combinations

Test period: 5 minutes:

Idle speed: oil moist

Limit speed: max. only drops

III Fuel return quantity at outlet of fuel filter housing

Idle speed and governed speed:

Up to engine end no. 027210 0.1 l/min
as of engine end no. 027211 0.3 l/min

Fuel return flow quantity at overflow valve

Idle speed: up to engine end no. 027210 0.9 to
1.4 l/min
from engine end no. 027211 0.9 to
1.7 l/min

Limit speed: up to engine end no. 027210 2.0 to
4.0 l/min
from engine end no. 027211 2.7 to
7.5 l/min

IV Fuel intake pressure upstream of fuel pump

Idle speed: 0.09 up to 0.12 bar

Limit speed: 0.35 bar

V Low pressure fuel circuit leaktightness

Test pressure: 5.0 bar.

Test period: 5 minutes:

Pressure drop 0.1 bar

Testing the low pressure fuel circuit

W07.15-1016-06

Diagram of fuel circuit

1 Fuel delivery pump (KFP)

2 Fuel filter (KF)

3 Fuel feed passage to PLD unit pumps

4 Leak fuel duct

5 Nozzle holder combination

6 Pressure pipe connection

7 Injection line

8 Overflow valve

9 Fuel return flow passage purging fuel of PLD unit pumps

10 PLD unit pumps (Y6 to Y11)

11 Return flow / leak fuel line

12 Fuel prefilter (KVF)

13 Fuel line to fuel prefilter

14 Fuel feed from fuel tank

14.1 Assembly valve in fuel feed

15 Fuel return flow to fuel tank

15.1 Assembly valve in fuel return flow

19 Bypass valve

20 Fuel hand priming pump

21 Fuel heat exchanger

A Fuel feed

B Fuel return flow/leak fuel

C Fuel feed (pressure side downstream of KFP and KF)

D Fuel high pressure side

Modification notes

23.5.05

Banjo bolt for fuel line on cylinder head

Engine 904.9, engine 906.9 without code MS8

*BA07.15-N-1006-01A

Banjo bolt for fuel line on overflow valve

*BA07.15-N-1007-01A

Removing/installing

1

Remove service cover

Danger!

Risk of explosion caused by ignition of flammable products, risk of poisoning caused by inhaling fuel vapors or swallowing fuel as well as risk of injury to skin and eyes exposed to fuel.

No fire, sparks, open flames or smoking.
Only pour fuels into suitable and appropriately marked containers.

Wear protective clothing when handling fuel.

AS47.00-Z-0001-01A

2

Carry out visual inspection of all fuel lines, screw connections and components

Run engine for about 2 to 3 minutes at limit speed.

Replace damaged or leaking parts. Re-tighten screw connections if necessary.

3.1

Inspect fuel prefilter element

Up to engine end no. 027210

Clean fuel prefilter element if necessary.

AP47.20-D-0753A

3.2

Inspect fuel prefilter element

As of engine end no. 027211

Replace fuel prefilter if necessary.

AP47.20-D-0730A

4

Inspect fuel filter element

Replace fuel filter element if necessary.

AP47.20-D-0780C

5

Connect up STAR DIAGNOSIS and read out fault memory

AD00.00-L-2000-04A

6

Increase set parameter of stationary speed limit to 4000 rpm with STAR DIAGNOSIS

Only engines fitted with stationary speed limit.

Note parameterized value.

Installation: reparameterize stationary speed limitation.

Checking

Conditions for tests

Engine must be at operating temperature.

Fuel temperature in fuel tank 40°C.

Collect escaping fuel.

The fuel which flows through during the tests must be free of bubbles.

7

Open end cover at fuel tank

8

Test fuel pressure downstream of fuel filter

Attach testers and measuring equipment to low pressure fuel circuit.

AR07.15-W-2000-01I

Conduct test

Up to engine end no. 002604

AD07.15-W-7001-01D

As of engine end no. 002605

AD07.15-W-7001-01F

*123589042118

*541589022100

*541589009100

9

Measure fuel return flow quantity at nozzle holder combinations

Attach testers and measuring equipment to low pressure fuel circuit.

AR07.15-W-2000-01L

Conduct test

AD07.15-W-7001-07F

*000589070300

*000589680300

*541589009100

Injection line to pressure pipe connection and unit pump.

*BA07.15-N-1004-01A

Banjo bolt for fuel line on cylinder head.

*BA07.15-N-1006-01A

If the fuel return flow quantity is within the tolerance range, it is not necessary to conduct any further tests.

10

Measure the fuel return flow quantity at the engine

Attach testers and measuring equipment to low pressure fuel circuit.

AR07.15-W-2000-01N

Conduct test

Up to engine end no. 027210

AD07.15-W-7001-06D

As of engine end no. 027211

AD07.15-W-7001-06F

*541589009100

Banjo bolt for fuel line on fuel pressure relief valve.

*BA07.15-N-1007-01A

11

Test fuel inlet pressure upstream of fuel pump

Attach testers and measuring equipment to low pressure fuel circuit.

AR07.15-W-2000-01P

Conduct test

AD07.15-W-7001-03D

*617589042100

*541589009100

12

Test low pressure fuel circuit in engine for leaks

Attach testers and measuring equipment to low pressure fuel circuit.

AR07.15-W-2000-01S

Conduct test

AD07.15-W-7001-08D

*123589042118

*541589022100

*541589009100

13

Install in reverse order

14

Bleed fuel system

Diesel injection system with unit pumps (MR/PLD)

Number

Designation

Engine
904.9,

Engine
906.9
without
code MS8

BA07.15-N-1004-01A

Injection line to pressure pipe connection and unit pump

Nm

35

BA07.15-N-1006-01A

Banjo bolt for fuel line on cylinder head

Nm

50

BA07.15-N-1007-01A

Banjo bolt for fuel line on overflow valve

Nm

50

Testing the low pressure fuel circuit
Testing the low pressure fuel circuit
Testing the low pressure fuel circuit
Testing the low pressure fuel circuit

000 589 68 03 00

High pressure hose

Ring wrench socket

Ring wrench

Tester

000 589 07 03 00

123 589 04 21 18

617 589 04 21 00

Testing the low pressure fuel circuit
Testing the low pressure fuel circuit

541 589 00 91 00

Adapter parts

Tester

541 589 02 21 00

Referenced documents