Test low pressure fuel circuit · ar0715i2000b · Mercedes-Benz WIS

AR07.15-I-2000B

Test low pressure fuel circuit

22.3.07

ENGINE 904.941 in MODEL 684.482

I07.15-0027-09

Components from fuel circuit

1 Fuel delivery pump

1.1 Pressure limiting valve (9.2 bar)

1.2 Check valve (0.2 bar)

2 Fuel filter

2.1 Fuel filter drain valve

2.2 Constant vent

3.1 Bypass (from fuel feed passage to fuel return passage)

5 Nozzle holder combination

8 Overflow valve (4.5 bar)

8.1 Constant vent (0.5 mm)

12 Fuel prefilter

12.1 Check valve

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 Throttle (0.5 mm)

18.2 Throttle (threaded restrictor)

B10 Fuel temperature sensor

R3 Flame glow plug

Y5 Flame starting system solenoid valve

Y6 Cylinder 1 unit pump

Y7 Cylinder 2 unit pump

Y8 Cylinder 3 unit pump

Y9 Cylinder 4 unit pump

A Fuel feed (suction side)

B Fuel return (leak fuel)

C Fuel feed (pressure side)

D Fuel high pressure side

E Fuel return (fuel filter drain)

Test points, test data

G Manometer test

H Fuel return flow quantity checking

a Fuel pressure downstream of fuel filter

b Fuel return flow quantity at nozzle holder combination

c Fuel return flow quantity at outlet of the fuel filter housing and at overflow valve

d Fuel intake pressure upstream of fuel pump

e Leaktightness of the low-pressure fuel circuit

I07.15-0028-06

Components of fuel circuit

1 Fuel delivery pump

2 Fuel filter

3 Fuel feed duct

4 Leak fuel duct

5 Nozzle holder combination

6 Pressure pipe connection

7 Injection line

8 Overflow valve (4.5 bar)

9 Fuel return duct

11 Leak fuel line (return)

12 Fuel prefilter

13 Fuel line (from fuel prefilter to fuel feed pump)

14 Connection for fuel feed line from fuel tank

15 Connection for fuel return line to fuel tank

16 Fuel feed line to flame starting system

Y6 Cylinder 1 unit pump

Y7 Cylinder 2 unit pump

Y8 Cylinder 3 unit pump

Y9 Cylinder 4 unit pump

A Fuel feed

B Fuel return (leak fuel)

C Fuel feed (pressure side downstream of fuel feed pump and fuel filter)

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

Modification notes

23.5.05	Banjo Bolt, fuel line to cylinder head	Engine 904.9, engine 906.9 without code MS8	*BA07.15-N-1006-01A
	Banjo bolt, fuel line to overflow valve		*BA07.15-N-1007-01A

 Danger!	Risk of accident caused by vehicle starting off by itself when engine is running. Risk of injury caused by contusions and burns during starting procedure or when working near the engine as it is running	Secure vehicle to prevent it from moving 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 and risk of injury to eyes and skin caused by contact with 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
1	Warm up engine to normal operating temperature	 In order to perform the following checks, the fuel temperature in the fuel tank (17) must be below 40°C and the fuel must be free of bubbles.
2	Attach Diagnosis Assistance System (DAS)
3	Parameterize a stationary speed limit to 4000 rpm	Only on engines fitted with stationary speed limit.
		 Previously note the current parameterized value.
4	Check filter insert for fuel prefilter (12)	 Clean or replace filter insert if necessary: 
		Clean filter insert for fuel prefilter	AP47.20-I-0730B
5	Check filter insert for fuel filter (2)	 Replace filter insert if necessary: 
		Replace filter insert for fuel filter	AP47.20-I-0780B
6	Check fuel lines, threaded connections and components of the fuel circuit for leaktightness and damage	 Allow engine to run for about 2 to 3 minutes at a maximum governed rpm and then stop again after completing a visual inspection of the engine. Retighten threaded connections if necessary or replace parts.
7	Bridge fuel prefilter with water separator	Only perform if a fuel prefilter with water separator is installed.
8	Open cap on fuel tank (17)
9	Install testers and measuring equipment in low pressure fuel circuit	 to check the fuel pressure downstream of the fuel filter (2).	AR07.15-W-2000-01I
			*123589042118
			*541589022100
			*541589009100
10	Test fuel pressure downstream of fuel filter (2)
	Fuel pressure downstream of fuel filter, testing hydraulics system MR (PLD)		AD07.15-W-7001-01F
11	Stop engine and restore original installation condition	 The engine panel remains removed.
12	Install testers and measuring equipment in low pressure fuel circuit	 to measure the fuel return quantity to the nozzle holder combinations.	AR07.15-W-2000-01L
			*BA07.15-N-1004-01A
			*BA07.15-N-1006-01A
			*000589070300
			*000589680300
			*541589009100
13	Check fuel return flow volume at nozzle holder assemblies (5)	 If the fuel return flow quantity is within the tolerance range, it is not necessary to conduct any further tests.
	MR (PLD) test of hydraulic system fuel return flow quantity at nozzle holder combinations		AD07.15-W-7001-07F
14	Stop engine and restore original installation condition	 The engine panel remains removed.
			*BA07.15-N-1004-01A
			*BA07.15-N-1006-01A
15	Install testers and measuring equipment in low pressure fuel circuit.	 To measure the fuel return flow quantity at the engine.	AR07.15-W-2000-01K
			*BA07.15-N-1007-01A
			*541589009100
16	Measure fuel return flow quantity at engine
	MR (PLD) test of hydraulic system fuel return flow quantity		AD07.15-W-7001-06F
17	Stop engine and restore original installation condition	 Replace all seal rings. The engine panel remains removed.
			*BA07.15-N-1007-01A
18	Install testers and measuring equipment in low pressure fuel circuit	 to check the fuel suction pressure upstream of the fuel feed pump (1).	AR07.15-W-2000-01J
			*617589042100
			*541589009100
19	Test fuel suction pressure upstream of fuel feed pump (1)
	Fuel vacuum upstream of fuel pump, MR (PLD) hydraulic testing		AD07.15-W-7001-03F
20	Stop engine and restore original installation condition
21	Install testers and measuring equipment in low pressure fuel circuit	 To check leaktightness of the low-pressure fuel circuit in the engine.	AR07.15-W-2000-01M
			*123589042118
			*541589022100
			*541589009100
22	Test low pressure fuel circuit in engine for leaks
	Low-pressure fuel circuit leaktightness, MR (PLD) hydraulic testing		AD07.15-W-7001-08F
23	Stop engine and restore original installation condition
24	Attach fuel lines on fuel prefilter with water separator again	Only perform if a fuel prefilter with water separator is installed.
25	The stationary speed limit is noted again, parameterize the original value	Only on engines fitted with stationary speed limit.
26	Disconnect Diagnosis Assistance System (DAS)
27	Bleed fuel system	 To do this allow engine to run for about a minute. The fuel system purges itself automatically while the engine runs.
28	Test vehicle power output on dynamometer	 All checks and measurements must have been conducted and any deficits there must have been removed.

 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, fuel line to cylinder head	Nm	50
BA07.15-N-1007-01A	Banjo bolt, fuel line to overflow valve	Nm	50

000 589 68 03 00

High pressure hose

Box wrench bit

Ring wrench

Testing unit

000 589 07 03 00

123 589 04 21 18

617 589 04 21 00

541 589 00 91 00

Adapter parts

Testing unit

541 589 02 21 00

Referenced documents

ad0715w700101f Fuel pressure downstream of fuel filter, MR. (PLD) hydraulic testing
ad0715w700103f Fuel vacuum upstream of fuel pump, MR. (PLD) hydraulic testing
ad0715w700106f MR. (PLD) test of hydraulic system fuel return flow quantity
ad0715w700107f MR (PLD) test of hydraulic system fuel return flow quantity at nozzle holder combinations
ad0715w700108f Low-pressure fuel circuit leaktightness, MR (PLD) hydraulic testing
ap4720i0730b Clean filter element of fuel prefilter
ap4720i0780b Replace fuel filter
ar0715w200001i Install test/measuring equipment in the low pressure fuel circuit
ar0715w200001j Install test/measuring equipment in the low pressure fuel circuit
ar0715w200001k Install test/measuring equipment in the low pressure fuel circuit
ar0715w200001l Install test/measuring equipment in the low pressure fuel circuit
ar0715w200001m Install test/measuring equipment in the low pressure fuel circuit
as0000z000501a 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.
as4700z000101a 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.