jcb G20 Operator's Manual page 128

Fuel lift pump not operating correctly (fuel supply in-
adequate).
Fuel is waxing due to extremely cold weather.
Fuel is contaminated or incorrect grade diesel fuel
used.
Fuel filter(s) blocked, fuel supply restricted.
Fuel drain return line blocked, not connected proper-
ly.
Cause
Condition only occurs at idle.
Engine is cold, coolant temperature sensor fault.
Fuel injection lines leaking.
Fuel is aerated.
Fuel lift pump not operating correctly (fuel supply in-
adequate).
Fuel filter(s) blocked, fuel supply restricted.
Fuel is contaminated or incorrect grade diesel fuel
used.
Inlet and exhaust valve clearances set incorrectly.
Engien compression low in one or more cylinders.
ECU or electrical sensor fault.
Worn or malfunctioning high pressure fuel pump
Camshaft or tappets damaged.
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Check that the lift pump is operating and delivering
fuel to the injection pump.
Verify by inspecting the fuel filter. Clean the system
and use acclimatised fuel.
Stop the engine.
Replace the fuel filters. Operate the engine with a
temporary supply of the correct grade of clean fuel.
WARNING: Dirty fuel will cause damage to the fuel
injection pump and injectors.
Check/replace the fuel filter(s).
Verify that the fuel return line is not obstructed and
connected to the top of the fuel tank.
Table 26. Engine - Poor Running
Remedy
Refer to Table 27.
Check the electrical connection at the coolant sen-
sor. Check the correct electrical wires for open or
short circuits. If engine will not reach operating tem-
perature, Table 24. Coolant - Under Temperature.
Replace defective high pressure fuel lines.
WARNING: DO NOT repair defective fuel lines. If
there is a fuel leak remove and discard the neces-
sary components and install new ones.
WARNING: Fine jets of fluid at high pressure can
penetrate the skin. Keep face and hands well clear of
pressurised fluid and wear protective glasses. If fluid
penetrates your skin, get medical help immediately.
Check the fuel system for loose connections and
possible air ingress points. Rectify and bleed the fuel
system.
Check that the lift pump operates and delivers fuel to
the fuel injection pump. Check the correct electrical
wires for open or short circuits.
Check/replace the fuel filter(s). Check fuel lines for
restriction.
Stop the engine.
Replace the fuel filters. Operate the engine with a
temporary supply of the correct grade of clean fuel.
Monitor the engine performance.
WARNING: Dirty fuel will cause damage to the fuel
injection pump and injectors.
Set the valve clearances to the recommended clear-
ances.
Check the engine compression.
Check the electrical connections at the sensors.
Do all the necessary fault finding checks before re-
moval of the high pressure fuel pump.
Inspect camshaft and tappets.
9831/0650-3
Maintenance
Fault-Finding
121