Fuel Rail Pressure Sensor (Engine management system - EDC)

Fuel Rail Pressure Sensor

The fuel rail pressure sensor is located on the end of the fuel rail. A diaphragm located within the sensor is in contact with the pressurised fuel. An electronic resistive element, attached to the diaphragm, distorts as the diaphragm changes in shape due to the pressure exerted by the fuel. The resistance values are converted into an analogue voltage within the pressure sensor and this signal is processed by the ECM. The ECM compares the signal to stored values to calculate current fuel pressure.

The fuel rail pressure sensor consists of the following components: l Sensor housing with electrical connection. l Printed circuit board with electrical evaluation switch. l Diaphragm with integrated sensor element.

Electrical input to the fuel rail pressure sensor is a 5 volts supply from the ECM. Output is an analogue voltage between 0.5 - 4.5 volts.

In the event of a fuel rail pressure sensor failure any of the following symptoms may be observed: l Engine will not start. l Severe loss of power. l Engine stalls.

Vacuum Control Module

The Vacuum control module is used by the ECM to control the Variable Nozzle Turbine (VNT) within the turbocharger unit.

The variable nozzle turbine improves turbine boost pressure by opening and closing internal vanes. The system uses signals from the boost pressure sensor, road speed signal and engine load to calculate a 'setpoint' boost pressure from an internal software 'map'. This in turn provides an angle for the vanes to be set to (between open and closed) to vary the boost pressure.