Troubleshooting chart
37
x =
Probable
o =
Possible
1.
EDC self-diagnosis or flash code output
2.
Starter turns over engine only slowly or not at all
3.
Starter turns, engine does not start, engine does not start / difficult to start when cold
4.
Engine stalls (dies) during operation, no longer starts (starter turns),
engine does not start / starts with difficulty when hot
5.
Sudden, temporary engine shut-down, engine does not reach full revs
6.
Engine only runs at idle speed, no throttle response
7.
Engine only runs at increased idle speed, no throttle response
8.
Rated engine speed distinctly reduced (even under no load)
9.
Reduced output in all ranges
10. Irregular engine operation, traction loss
11. Unstable idle speed, engine hunting, misfiring, knocking in engine
12. Engine judder
13. Unusual combustion noise
14. Excessive smoke emission: White smoke / blue smoke
15. Excessive smoke emission: Black smoke
16. Engine temperature too high (coolant loss)
17. Intermediate engine speed control cannot be activated / does not switch off, engine revs too
high
18. Fuel consumption too high
19. Lubricating oil pressure too low
20. Lubricating oil pressure too high
21. Lubricating oil consumption too high
22. Engine too loud / mechanical noise
Possible causes
x x
x
x
Compression deficient, or more than 3
−
4 bar pressure difference between indivi-
dual cylinders
x
x
x
Valve seats leaking
o
x
x
Increased power consumption due to faulty secondary consumers such as hy-
draulic pumps, fan etc., power take-off engaged
x
x
x
x
x Air cleaner soiled or clogged, charge-air system leaking, air inlet / exhaust lines
clogged / leaking
x x x x
x x
x
x
x
Fuel low pressure system: fuel tank, prefilter, water trap faulty / clogged / mould /
fungal attack, fuel unsuitable / heavily contaminated (paraffin added)
x x x
x x x
x
x
Fuel low pressure system: Fuel lines leaking, broken, clogged
x x x
x x
x
x
Fuel low pressure system: AIR in the system (turn on ignition when bleeding the
system)
x x x
x x x x
x
x
Fuel low pressure system: delivery pump, overflow valve, main filter
x
x
x x x o x
x
Fuel high pressure system: nozzles faulty / clogged / leaking / coked
x
x x x
o
Fuel high pressure system: pressure lines
−
constriction, cavitation, leaking
x
x
o x x x x
o
Fuel high pressure system: injection pump worn / incorrectly set
o
x o
o
Fuel high pressure system: injection pump constant-pressure control valve / re-
turn flow constrictor faulty
x x x
o x
Safety relay defective, drive faulty
o o
o
x
o x x
x
Injection pump / engine synchronisation: start of delivery incorrect (basic installa-
tion), start of delivery set incorrectly
x
x x x
o
x o
Injection pump controller: stiff movement
−
fuel volume regulator (control devia-
tion)
x
x x x
o
Control rod position sensor in regulator: connection lines, break, short-circuit
o
o
o
Control rod position sensor in regulator: set incorrectly
x
x
o
Control rod position sensor in regulator: capacitance reserve of the wiring har-
ness too low (e.g. water penetrated wiring harness)
x
o x o
o
Injection pump: fuel volume set incorrectly / uniform delivery, lower idle speed set
too low
x
o x x
x
Fuel volume actuating solenoid in regulator: connection lines, break, short-circuit
x
x
o o o
CAN control system has failed / is defective: Connection lines, short-circuit,
break
x
EDC rpm sensor defective, implausible with auxiliary rpm sensor, line defective
x o
EDC rpm sensor, polarity reversed
x
EDC auxiliary rpm sensor defective, implausible with rpm sensor, line defective
x
x x x o
o o
o
EDC detects incorrect engine speed (interference signal on rpm sensor line)
x
x x x
o
Both rpm sensors faulty, line fault
Summary of Contents for D 2876 LE 101
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Page 3: ...3 Operating Instructions MAN Industrial Diesel Engines...
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Page 39: ...Notes 39...
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