An EUI comprises an individual camshaft driven plunger pump for each cylinder which is capable of delivering fuel at very high pressures (up to 2000 bar). These high injection pressures are absolutely essential to enable engines to meet current and future emissions legislation. The actuator is a solenoid controlled valve which is operated by signals from a microprocessor. The EUI system incorporates full electronic control with pilot injection being employed to reduce noise. At the same time, sensors around the engine feed a continuous stream of data to the ECU which calculates the exact amount and timing of fuel injected.
Due to the complex nature of the Electronic Unit Injector and the extremely high operating pressure within the system, in the past, the only service option was to replace the entire unit with a new or factory re-manufactured unit. Repair was not possible, as the traditional workshop equipment and environment was not suitable for the task.