Fuel injectors are small electrical components that are used to deliver fuel via a spray directly into the intake manifold in front of the intake valve in a diesel engine. Diesel fuel injectors are quite complied; the injector has a high micron filter on the top inlet side which corresponds to small hypodermic sized holes on the bottom for the atomizing of the diesel fuel. The diesel fuel acts as a lubriing source for the injector’s internal parts. The main source of failure for injectors is water in the fuel. When water in the fuel displaces the lubriing properties the internal parts wear down quickly and the injector as a whole can fail rather quickly.