Diesel Mechanic : Servicing & specialist repairs:

Mobile technician : Vehicle Breakdown callout * available to Shrewsbury Shropshire & Mid Wales areas (*subject to availability). Enquiries welcome.

Diesel Fuel Injection Engine Diagnostics Troubleshooter Chart

Possible Diesel Engine Faults

Problem
Possible Cause

Engine will not Crank

Low starter battery voltage.
Ignition switch faulty or wiring.
Starter motor or related wiring fault.
Engine immobiliser locked.
Engine may be seized
Engine may be hydraulically locked due to fluid leak in to cylinders

Engine Cranks but will not Start

Engine immobiliser locked.
No fuel in the tank.
Incorrect fuel in the tank.
Fuel supply line blocked
Fuel primer pump inoperative.
Air entering fuel system.
Pre heater (glow) plugs / relay / wiring faulty.
Incorrect valve timing.
Incorrect Injection pump timing.
High pressure fuel injection pump faulty.
No engine Rpm signal from ckp (may set fault code P0335)
No camshaft sensor signal (cylinder phasing error, may set fault code P0341)
Fuel Injectors faulty (may set P0200 or related fault code)
Fuel injector pipes incorrectly fitted.
High pressure system loss of pressure. Common rail pressure fault (may set P087 or P088 fault code)
Failure of an electronic control system sensor / wiring.
Fault codes logged on Diesel control unit (DCU) preventing startup. Failure of Diesel control unit .
Air intake System blocked / restricted.
Exhaust system blocked or restricted.
Engine condition causing low compression pressure.
Diesel injection pump not delivering fuel

Engine Starts then stops within a few seconds

Restricted fuel supply. Check fuel tank, pipes and filters.
Air entering fuel system.
Immobiliser fault.
Faulty or incorrect ESOS (engine stop solenoid) or ELAP.
Electronic engine control fault. Test ECU and wiring.
Air intake restriction.
Exhaust system blocked / restricted. EGR valve stuck or blocked.

Unstable Idling

Fuel supply restriction.
Air entering fuel system.
Electronic control system or wiring fault.
Blocked /leaking /inoperative fuel Injector.
Mechanical Injection pump fault (possible pump phasing).
Incorrect pump to engine timing.
Valve timing or compression problem.
Heater plug circuit fault.
Air intake system fault.
Exhaust partially blocked.
Exhaust gas recirculation (EGR) system fault.
Engine compression fault.

Excessive mechanical noise.


Incorrect engine oil level
Incorrect engine oil specification
Insecure engine component / mechanical failure.
Incorrectly fitted timing belt.
Incorrect pump / valve / engine timing.
Incorrect fuel injector calibration / fault.
Incorrect Injection pump calibration.
Precombustion chamber loose in cylinder head.
Excessive engine mechanical noise may be detected by the Knock sensor setting fault code P0325
Exhaust system blockage.

Excess black exhaust smoke emission

Faulty / dirty fuel injectors.
Incorrect injection pump to engine timing.
Injection pump overfuelling / incorrect calibration.
Fuel Injection pump excess fuel device fault.
Electronic control system fault.
Restricted air intake or air filter blocked.
Engine not reaching operating temperature.
Heater plug post heat fault.
Turbocharger oil seals failing allowing engine oil to leak into air intake system.
Low boost pressure from turbo or intake system leaks.

Excess White / Grey smoke emission

Fuel injector opening pressure too low.
Incorrect valve timing.
Incorrect injection pump timing.
Low cylinder compression pressure.
Restricted air intake.
Low turbocharger boost pressure due to worn turbo / intake system fault / boost control.
Water entering combustion chambers due to head gasket failure, cylinder head or block cracked.

Engine Misfire
(may set P0300 or related fault code)

Air entering fuel system.
Fuel line restriction.
Faulty fuel injector / calibration.
Wiring fault.
Incorrect valve timing.
Incorrect valve clearance.
Compression loss.
Faulty Injection pump.

Random engine acceleration

Engine gaining extra fuel from supplementary source, eg ,
mechanical pump boost control diaphragm leaking fuel into turbo through boost control pipework.
Excessive engine oil level : Engine inducting engine oil & using as a fuel.
Electronic control system fault.
Faulty fuel injection pump.
Accelerator linkage insecure.
Throttle position actuator stuck or wiring fault

Slow deceleration

Restricted fuel return line.
Insecure accelerator linkage or return spring missing.

Low or Insufficient power

Restricted fuel supply.
Contaminated fuel.
Injectors faulty.
Fuel Pump calibration fault or worn pump.
Incorrect valve or fuel pump timing.
Fuel pump stop solenoid not opening fully.
Electronic diesel MPROP Solenoid sticking or dirty
Accelerator linkage insecure or travel restricted.
Electronic engine control system or wiring fault.
Electronic diesel control system in limp home mode or restricted mode.
Turbocharger system fault.
Air mass or Airflow meter fault (may set P0100 fault code)
Restricted exhaust system.
Exhaust Gas Recirculation fault (may log ecu fault codes eg, P0400 )
Road speed limiter incorrectly set or system fault.
Engine temperature fault.
Vehicle braking system not releasing.

Engine Overheating

Low coolant level, or coolant leakage, cooling system pressure loss,cooling pressure cap faulty.
Water pump impellor failure
Blocked radiator ; internally or airflow.
Faulty viscous fan , or fan motor not operating , wiring fault.
Incorrect injection pump calibration.
Faulty fuel injectors.
Incorrect injection pump timing , or electronic control system fault.
Mechanical fault with engine, head gasket failure, cracked cylinder head, cracked cylinder block .
Excessive engine load due to vehicle brakes sticking on etc.

Engine will not shut off

Engine gaining a supplementary fuel supply.
Ignition switch / wiring fault leaving fuel stop solenoid energised.
Faulty fuel stop solenoid.
Stop control linkage disconnected or broken.

DIESEL FUEL INJECTION EQUIPMENT
Fuel hose
Filters
Pumps
Injectors
Diesel Glow Plugs and Preheat timer Relays

DIESEL ENGINE REPAIR TOOLS
Injector Pullers

DIESEL PUMP REPAIR PARTS
Bosch type lift pump plunger type HC080295

DIESEL LIFT PUMP REPAIR KITS
CAV filter head type HC080783

BOSCH PE type PUMP PARTS
PE6P Repair kit HC090027

BOSCH RSV type PUMP PARTS
RSV Repair kit HC090147

BOSCH VE type PUMP PARTS
VE Repair kit HC090092
VE Gasket Kit HC090165
VE Gasket Kit HC090212

CAV SIMMS MINIMEC PUMP PARTS
4 cyl minimec Gasket Kit HC090222
Governor Kit HC090244

CAV DPA PUMP PARTS
Liner HC08015
Repair Kit HC090047
Rotor Vane Set HC080614 HC080773
Top cover gasket HC080205
Throttle Shaft HC080188
Triangle Gasket HC080933

CAV DPC PUMP PARTS
Boost Controller Diaphram HC080969
DPC turbo repair kit HC090136

CAV DPS PUMP PARTS
Repair Kit HC090055

STANADYNE DB2 PUMP PARTS
Gasket Kit HC090242

STANADYNE DB4 PUMP PARTS
Gasket Kit HC090344

2.5 Transit Diesel Parts
Lift Pump HC090197
Lucas Epic pump
(turbodiesel) gasket kit HC090294

FLAME PLUG
11.5V 12A HC100177
12v 6A HC100580

GLOW PLUG THREAD REPAIR INSERT
M12 x1 external dia : M10 x1 internal dia HC192578