Symptoms Diagnosis - Fuel Injectors

The quality of fuel that your engine uses or presence of water in fuel can lead to issues in your fuel injectors and nozzles. It is, therefore, important that you understand what these problems can be and recognise their potential causes.

Fuel contamination is the main reason behind fuel system failures

Fuel injectors are carefully engineered systems that need to be kept in good working order for your engine to perform properly. The holes in an injector nozzle are as small as a human hair yet are exposed to the hostile environment of an engine cylinder.

Perkins fuel injectors open and shut many times a second, with over 9.5 billion activations in a lifetime. The power generating set operates at 1800 rpm. Over one hour, this means each injector operating a single shot mode with a 4 stroke cycle delivers 54,000 events. These figures are even greater in high speed engines and multi-shot modes of operation. While Perkins fuel injectors are incredibly reliable, problems can occur.

The most common indications of a fuel injection system problem:

• Poor starting
• Loss of power, lower gear selection
• Increased fuel consumption
• Poor idling
• Excessive / black smoke
• Cylinder knock, uneven running or misfiring

Fuel injectors can wear over time leading to a decline in performance, especially in the presence of high levels of fuel contamination. Injector wear occurs on seat angles, causing poor sealing and / or incorrect spray patterns. Contamination can also lead to blocked injector holes, causing further impact on spray patterns.

Injector problems can occur when a poor-quality repair has taken place, due to the following issues; injector not sealing in cylinder head, two sealing washers under injector or incorrect injectors fitted. Other fuel system issues may also lead to injector issues; high pressure pipe leaks or restrictions, and nozzle valve sticking due to fuel contamination build up.

Contributing factors for failure

Fuel injector system wear is increased by lower quality fuels and water in the fuel system. This can be due to:

• Lower quality fuels, especially those without lubrication additives
• Particle contamination in fuel especially when inferior fuel filters have been used
• Water contamination of diesel fuel leading to corrosion and wear of injectors

The effect of dirt and water contamination can be limited by using correct fuel filters at the regular service intervals.

Many modern injectors can’t be serviced or cleaned effectively and should be replaced.