Inspect fuel leakage visually from fuel tank and fuel pump mounting point.

Inspect fuel quality and inside of fuel tank after removing fuel pump.

Check contamination of fuel filter and foreign substances in the fuel filter.

Are the fuel quality, fuel tank and fuel filter normal?

	▶ Fuel and fuel system are normal.
	▶ Replace fuel. ▶ Repair/replace fuel system.

Water or foreign substance is mixed.

Gasoline or kerosene is mixed.

Solvent or chemical substance is mixed.

Can cause damage in engine performance and fuel system

Water : frozen at low temperature and cause corrosion, wear, blocking, sticking (in the fuel system)

Substances : fuel system block or stuck.

olvent or chemical substance : lubrication function of diesel fuel has declined. ⇒ Inside of high fuel system has worn ⇒ abnormal fuel injection because fuel system is blocked by metallic substances or sludge.

Carbon deposit in the injector nozzle and a combustion chamber by incomplete combustion. ⇒ Excessive black smoke(In case of DPF vehicle : DPF could be damaged)

Hard starting in the winter time by using diesel fuel includes inappropriate paraffin substances.