Why Do They Fail?

• Wear and tear in valves and seals due to constant pressure cycling

• Fuel contamination (water, rust, or debris) blocking or damaging components

• Electrical failure in solenoids or control valves

• Air leaks in primer assemblies or faulty non-return valves

• Heat and vibration causing premature fatigue in connectors and housings

• Float arm or level sensor issues, leading to inaccurate fuel gauge readings

• Split housings or cracked pipe connectors, causing leaks or pressure loss

Symptoms of Faulty Diesel System Components

• Hard starting or failure to start due to air ingress or low fuel pressure

• Engine cutting out unexpectedly caused by faulty stop solenoids

• Loss of power or hesitation under load

• Check Engine Light (MIL) with fuel rail pressure or injection control codes

• Excessive smoke or poor fuel economy from incorrect fuelling

• Visible fuel leaks around primers or valve connectio

Fitting Tips

1. Always check for fuel contamination before fitting new diesel components.

2. Bleed the system properly after replacing valves or hand primers to avoid air locks.

3. Inspect electrical connectors and harnesses when fitting solenoids or control valves.

4. Replace sealing washers or gaskets where supplied — never reuse old seals.

5. Use manufacturer-recommended torque values to avoid damage to delicate housings.