EGR Valve: Description and Operation

EGR Valve:

PURPOSE
Allows exhaust gas to enter the intake manifold.

LOCATION
On top of intake manifold, behind TBI unit.

OPERATION AND CONSTRUCTION
This valve is controlled by a flexible diaphragm which is spring loaded to hold the valve closed. Vacuum applied to the top side of the diaphragm overcomes spring pressure and opens the valve in the exhaust port, allowing exhaust gas into the intake manifold and thus to the cylinders.