Ford Workshop Service and Repair Manuals

The engine is fitted with an electronically controlled variable vane turbocharger. The turbocharger is fixed to the exhaust manifold by a retaining clamp. The turbocharger consists of two elements, a turbine and a compressor both installed on a single shaft.

The turbocharger bearings are supplied with oil from the engine.

The turbine uses the flow of the exhaust gas to drive the compressor. The compressor draws air through the air cleaner and forces it into the intake manifold.

The turbocharger is designed to improve engine induction and engine performance. The list below details the possible concerns relating to turbocharger performance.

• High engine speed produces excessive turbine speed and therefore creates excessive turbocharger boost pressure.
• Low engine speed does not produce sufficient turbine speed and therefore not enough turbocharger boost pressure is achieved.

The turbocharger does not have a wastegate control valve. Instead, it has variable turbocharger vanes, which are located in the turbocharger turbine housing and these direct the exhaust gas flow into the turbocharger turbine. The turbocharger vanes act as the control for the turbocharger boost pressure.

The turbocharger produces its full turbocharger boost pressure over the entire engine speed range, not just at high engine speed. This is achieved through the adjustment of the vanes and the resulting change in the flow of the exhaust gas.

The speed of the exhaust gas flow within the turbocharger is increased independent of engine speed by varying the intake cross section in front of the turbocharger turbine. This is achieved by adjusting the angle of the vanes controlling the exhaust gas flow into the turbocharger turbine and this drives the turbocharger turbine faster. The higher turbocharger speed produces a high turbocharger boost pressure at all engine speeds.

The powertrain control module (PCM) controls the turbocharger vanes by means of an electronic vane adjustment solenoid attached to the turbocharger.

Regulation at Low Engine Speed

At low engine speeds the PCM operates the vane adjustment solenoid. The vane adjustment solenoid moves the adjusting ring so that the vanes are set at a shallow angle. The shallow intake cross section this creates for the stream of exhaust gas allows the turbocharger boost pressure to build up rapidly and easily at low engine speeds.

Regulation at Moderate Engine Speed

As the engine speed increases and the quantity of exhaust gas increases, the vane adjustment solenoid moves the adjusting ring so that the vanes are set at a steeper angle. The steeper angle opens the intake cross section effectively reducing the gas flow and turbine speed, while maintaining constant turbocharger boost pressure.

Regulation at Maximum Engine Speed

As the engine speed increases the intake cross section in front of the turbocharger turbine is continuously enlarged. The turbine speed and hence the quantity of the air supplied to the engine, is adjusted to suit the engine speed. This means that the turbocharger boost pressure remains optimized over all engine speeds.

The maximum position of the turbocharger vanes (maximum opening cross section) is also an emergency position, in the event of an electrical concern. This lowers the chance of engine damage due to excessive boost in the event of a turbocharger control concern.

Fixed Vane Turbocharger

The turbocharger consists of two elements, a turbine and a compressor both installed on a single shaft and are contained within a housing.

The turbocharger bearings are supplied oil from the engine through the oil supply pipe. The oil is returned to the oil pan through the oil return tube.

The turbine element of the turbocharger uses the energy of the exhaust gas to drive the compressor. The compressor draws in air through the charge air cooler.

The turbocharger is governed by means of a wastegate. The wastegate redirects some of the exhaust gas past the turbine. The wastegate is controlled by a waste gate control solenoid which is preset during manufacture and must not be tampered with.