Ford Workshop Service and Repair Manuals

The exhaust gas recirculation (EGR) system allows a measured quantity of exhaust gas to be directed back to the intake manifold. The exhaust gas is introduced to the incoming charge in the intake manifold, where it dilutes the air fuel mixture and lowers the peak gas temperature, reducing nitrogen oxide exhaust emissions.

The exhaust gas is drawn through a passage within the cylinder head from the exhaust manifold to the intake manifold by the EGR valve.

The EGR valve is controlled by an input from the powertrain control module (PCM).

The positive crankcase ventilation (PCV) system consists of a valve mounted in the crankcase vent oil separator (attached to the cylinder block) and two hoses. One PCV hose connects the PCV valve to the intake manifold, the other PCV hose connects the valve cover to the air cleaner.

Under idle and part throttle conditions, the crankcase vapor flows through the intake manifold into the combustion chambers where the vapor is burnt during combustion.

Under full throttle conditions, the crankcase vapor flows from the valve cover into the air cleaner through the PCV hose.