PT PLN (Persero) is one of the BUMN (State Owned Enterprises) companies in charge of the electricity business sector in Indonesia. As a company that sells products and services, PT. PLN (Persero) must provide the best service in order to create satisfaction. Customer satisfaction is a requirement for the company to survive and is very important in forming a good image for the company. Based on practical work experience at PLTD Natuna, it was found that the most common problems that occurred in the MTU 12V 4000 G23 engine occurred in the injectors. The most common thing that can be seen when the injector is damaged is the appearance of black smoke on the MTU engine combustion results due to incomplete combustion. One of the efforts made is to replace a new injector or by disassembling the injector on the MTU engine for repair, so that the MTU engine injector can be used again.