56
Fault Finding
CHART A6—Engine poor running at idle
Cause
Remedy
Engine is cold. Cold starting aid is not
working.
Check for the correct operation of the cold start advance. If the
engine will not reach operating temperature, refer to Chart D3.
Idle speed too low for accessories. Adjust the idle speed. Refer to the machines service manual for
correct adjustment procedures and idling speed.
Engine mounts over-tightened, damaged or
loose.
Verify the condition of the mounts, and replace/adjust as
necessary.
Fuel injection lines leaking. Inspect and correct as required leaks in the high pressure lines,
fittings injector sealing washers, or delivery valves.
WARNING: Fine jets of fluid can penetrate the skip. Keep face
and hands well clear of pressurised fluid and wear protective
glasses. If fluid penetrates your skin seek 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 inadequate).
Check that the lift pump is operating and delivering fuel to the
injection pump.
Fuel filter(s) blocked, fuel supply restricted. Check/replace the fuel filter(s). Check fuel lines for restriction.
Fuel is contaminated or incorrect grade of
diesel used.
Refer to Fluids & Lubricants section for recommended diesel
fuels. If the fuel is suspect, verify by operating the engine with
clean fuel from a temporary tank.
Inlet and exhaust valve clearances set
incorrectly.
Set the valve clearances to the recommended clearances.
Engine compression low in one or more
cylinders.
Check the engine compression.
Injection pump timing incorrect. If the pump has recently been removed and replaced the timing
could be incorrect if the correct removal procedures were not
followed.
The timing can only be checked by a FIE specialist using the
correct equipment.
One or more injector worn or
malfunctioning.
Check and externally clean the injector. If the problem still
persists, the injector must be checked by a FIE specialist or replace
with new.
Worn or malfunction fuel injection pump
(FIP). Injection pump not delivering fuel.
Check for operation of the FIP.
The FIP must be taken to a local FIE specialist to have the fuel
delivery timing checked. Ensure that all obvious causes have been
eliminated before removing the FIP. (Needs to be, Delphi DP210
capable agent for mechanical engines and for common rail
electronic engines see Delphi agent or JCB dealer
(www.delphi.com or www.jcb.com)
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