jcb G20, Operator'S Manual

Page: 128 / 177

Maintenance
Fault-Finding
121 9831/0650-3 121
Fuel lift pump not operating correctly (fuel supply in-
adequate).
Check that the lift pump is operating and delivering
fuel to the injection pump.
Fuel is waxing due to extremely cold weather. 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.
Fuel is contaminated or incorrect grade diesel fuel
used.
WARNING: Dirty fuel will cause damage to the fuel
injection pump and injectors.
Fuel filter(s) blocked, fuel supply restricted. Check/replace the fuel filter(s).
Fuel drain return line blocked, not connected proper-
ly.
Verify that the fuel return line is not obstructed and
connected to the top of the fuel tank.
Table 26. Engine - Poor Running
Cause Remedy
Condition only occurs at idle. Refer to Table 27.
Engine is cold, coolant temperature sensor fault. 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.
Fuel injection lines leaking.
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.
Fuel is aerated. Check the fuel system for loose connections and
possible air ingress points. Rectify and bleed the fuel
system.
Fuel lift pump not operating correctly (fuel supply in-
adequate).
Check that the lift pump operates and delivers fuel to
the fuel injection pump. Check the correct electrical
wires for open or short circuits.
Fuel filter(s) blocked, fuel supply restricted. 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.
Fuel is contaminated or incorrect grade diesel fuel
used.
WARNING: Dirty fuel will cause damage to the fuel
injection pump and injectors.
Inlet and exhaust valve clearances set incorrectly. Set the valve clearances to the recommended clear-
ances.
Engien compression low in one or more cylinders. Check the engine compression.
ECU or electrical sensor fault. Check the electrical connections at the sensors.
Worn or malfunctioning high pressure fuel pump Do all the necessary fault finding checks before re-
moval of the high pressure fuel pump.
Camshaft or tappets damaged. Inspect camshaft and tappets.