jcb G20 Operator's Manual page 132

One or more fuel injector worn or malfunctioning.
Worn or malfunctioning high pressure fuel pump.
Cause
Fuel injection lines leaking.
Fuel tank cap vent/breather blocked.
Fuel is aerated.
Electrical sensor fault.
One or more fuel injector worn or malfunctioning.
Worn or malfunctioning high pressure fuel pump.
Cause
Engine not running smoothly/misfiring.
Oil level over-full.
Fan damaged or accessories faulty.
Fan hub faulty.
Engine mounts loose or broken.
Inlet and exhaust valve clearances set incorrectly.
Engine compression low in one or more cylinders.
Alternator bearing worn or damaged.
Flywheel housing misaligned.
Electrical sensor fault.
Drive line components worn or unbalanced.
Table 34. Engine - Exhaust Smoke Excessive (Black Smoke)
Cause
Engine being lugged down.
Air intake or exhaust system blocked.
Air leak between the turbocharger and the intake
manifold (Turbocharged machines only).
Exhaust leak at the Manifold or Turbocharger (Tur-
bocharged machines only).
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Check the electrical connections at the injectors.
Do all the necessary fault finding checks before re-
moval of the high pressure fuel pump.
Table 32. Engine - RPM Surges
Remedy
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.
Inspect and rectify as required - replace cap if neces-
sary.
Check the low pressure fuel system for loose con-
nections and possible air ingress points. Rectify and
bleed the fuel system.
Check the electrical connections at the sensors.
Check the electrical connections at the injectors.
Do all the necessary fault finding checks before re-
moval of the high pressure fuel pump.
Table 33. Engine - Vibration Excessive
Remedy
Refer to Table 27.
Check oil level.
Check/replace the vibrating component.
Inspect/replace the fan hub. Refer to workshop man-
ual.
Check/replace engine mounts. Refer to the
machine's service manual for correct installation and
torque figures.
Set the valve clearances to the recommended clear-
ances.
Check the engine compression.
Check/replace the alternator.
Check/correct flywheel alignment.
Check the electrical connections at the ECU (Elec-
tronic Control Unit) and sensors.
Check and inspect drive line components such as
propshafts. Refer to workshop manual.
Remedy
Use appropriate gear for task.
Visually check the air intake and exhaust system for
blockage or obstruction - remove as required. Check
the air filter elements for signs of blocking - replace
as required.
Check/correct leaks in the air crossover tube, hoses,
or manifold cover.
Check/correct leaks in the manifold or turbocharger
gaskets. Look for a cracked manifold.
9831/0650-3
Maintenance
Fault-Finding
125