The key cause of injector failures are: Poor fuel filtration Fuel contamination Incorrect installation Always follow the engine manufacturer's maintenance procedures. The majority of diesel engine problems stem from contaminated fuel. Common problems include corrosion from excessive water in the fuel, micro fine particles in the fuel and improper fuel storage, which is caused by water in the fuel. There are two ways in which water can get into the fuel: through the delivery system and through the tank vent.