AR07.15-W-2000F | Testing the low pressure fuel circuit | 13.7.98 |
ENGINES 904.905 /906 /907 /921 ## as of 040488
ENGINES 904.909 /910 /911 /915 /916 /917 /922, 906.910 /911 /915 /916 /919 /920 /921 /922 /923 /925 /926 /927 /928 /939 /940 /941 /942 /943 /951 /952
W07.15-1015-09
Diagram of fuel circuit
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
3.1 Bypass from fuel feed passage to return flow passage
5 Nozzle holder combination
8 Overflow valve (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 fuel line
18.2 Restrictor (threaded restrictor) in flame fuel line
B10 Fuel temperature sensor
R3 Flame 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 PLD unit pumps)
E Fuel return flow (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: 4.3 bar
Limit speed: 4.0-6.5 bar
II Fuel return flow quantity at nozzle holder combinations
Test time: 5 min
Idle speed: oil moist
Limit speed: max. only drops
III Fuel return flow quantity at outlet of fuel filter housing
Idle speed and limit speed: 0.3 liters/min
Fuel return flow quantity at overflow valve
Idle speed: 0.9-1.7 liters/min
Limit speed: 2.7-7.5 liters/min
IV Fuel intake pressure upstream of fuel pump
Idle speed: 0.09 up to 0.12 bar
Limit speed: 0.4 up to 0.5 bar
V Low pressure fuel circuit leaktightness
Test pressure 10 bar, test period: 5 min, pressure
drop 0.25 bar
W07.15-0083-06
Diagram of fuel circuit
Shown on engine 906
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
15 Fuel return flow to fuel tank
16 Fuel feed to flame starting system
A Fuel feed
B Fuel return flow/leak fuel
C Fuel feed (pressure side downstream of KFP and KF)
D Fuel high pressure side (downstream of PLD unit pumps)
8 Overflow valve (4.5 bar)
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 KVF to KFP
14 Fuel feed from fuel tank
Modification notes
23.5.05 | Banjo bolt for fuel line on cylinder head | Engine 904.9, engine 906.9 without | |
Banjo bolt for fuel line on overflow valve |
| Removing/installing | ||
Danger! | Risk of injury caused by being caught or pinched as cab is tilted | Ensure that no one is within the tilting range of the cab as it is being tilted. Always tilt the cab all the way to the end position and secure with the safety strut. | |
1 | Tilt cab | ||
| Notes on tilting the cab | Models 375, 670-679, 950-954, 957, 970-976 | |
2 | Remove side soundproofing on left | ||
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. Wear protective clothing when handling fuel. | |
3 | Carry out visual inspection of all fuel lines, screw connections and components | Run engine for about 2-3 minutes at limit speed. Replace damaged or leaking parts. Re-tighten screw connections if necessary. | |
4 | Inspect fuel prefilter element | Replace fuel prefilter element if necessary. | |
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5 | Inspect fuel filter element | Replace fuel filter element if necessary. | |
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6 | Connect diagnosis system | ||
| Connect up STAR DIAGNOSIS and read out fault memory | Model 375, 950-954, 957, 970-976 | |
7 | Increase parameter of stationary speed limit to 4000 rpm | Only engines fitted with stationary speed limit. Note limit parameterized. | |
Installation: reparameterize stationary speed limitation. | |||
Checking | |||
| Conditions for tests | If Racor fuel prefilter is installed, detach this and connect fuel lines to fuel prefilter. | |
Engine must be at operating temperature. Fuel temperature in fuel tank 40°C. Collect escaping fuel. The fuel which flows through during the test must be free of bubbles. | |||
8 | Open cap on fuel tank | ||
9 | Test fuel pressure downstream of fuel filter | Attach test and measuring equipment to low pressure fuel circuit. | |
| Conduct test | ||
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10 | Measure fuel return flow quantity at nozzle holder combinations | Attach test and measuring equipment to low pressure fuel circuit. | |
| Conduct test | ||
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If the fuel return flow quantity is within the tolerance range, it is not necessary to conduct any further tests. | |||
11 | Measure the fuel return flow quantity at the engine | Attach test and measuring equipment to low pressure fuel circuit. | |
| Conduct test | ||
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12 | Test fuel inlet pressure upstream of fuel pump | Attach test and measuring equipment to low pressure fuel circuit. | |
| Conduct test | ||
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13 | Test low pressure fuel circuit in engine for leaks | Attach test and measuring equipment to low pressure fuel circuit. | |
| Conduct test | ||
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14 | Install in reverse order | ||
15 | Bleed fuel system | ||
16 | Test vehicle power output on dynamometer. | Only after all the tests or measurements have been carried out and any defects rectified: If no improvement in fuel consumption or performance has been achieved, connect a fuel consumption measuring system. |
Diesel injection system with unit pumps (MR/PLD)
Number | Designation | Engine Engine | ||
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 | |
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
541 589 00 91 00
Adapter parts
Tester
541 589 02 21 00
Referenced documents
- ad0000w200004a Connect STAR DIAGNOSIS and read out fault memory
- 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
- ah6080n000301a Notes on tilting the cab
- ap4720w0730b Clean filter element of fuel prefilter
- ap4720w0780b 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
- 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.
- as6080z000101a Risk of injury caused by body parts being pinched or crushed as cab is tilted