NC SW6 Maintenance Instructions Manual page 55

CHART A5—Engine poor running
Cause
Condition occurs only at idle.
Engine is cold. Cold starting aid is not
working.
Fuel injection lines leaking
Fuel is aerated
Fuel lift pump not operating correctly (fuel
supply inadequate)
Fuel filter(s) blocked, fuel supply restricted
Fuel is contaminated or incorrect grade of
diesel used
Inlet and exhaust valve clearances set
incorrectly
Engine compression low in one or more
cylinders
Injection pump timing incorrect
One or more injector worn or malfunctioning Check and externally clean the injector. If the problem still
Worn or malfunction fuel injection pump
(FIP). Injection pump not delivering fuel
Camshaft or tappets damaged
Fault Finding
Refer to Chart A6 for possible poor running at idle faults.
Check for the correct operation of the cold start advance. If the
engine will not reach operating temperature, refer to Chart D3.
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.
Check the fuel system for loose connections and possible air
ingress points. Rectify and bleed the fuel system.
Check that the lift pump is operating and delivering fuel to the
injection pump.
Check/replace the fuel filter(s). Check fuel lines for restriction.
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.
Set the valve clearances to the recommended clearances.
Check the engine compression.
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.
persists, the injector must be checked by a FIE specialist or replace
with new.
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)
Inspect camshaft and tappets.
Remedy
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